Total Available Carbohydrate Research Articles

Optimization of Solid-State Fermentation of Switchgrass Using White-Rot Fungi for Biofuel Production

Biological delignification using white-rot fungi is a possible approach in the pretreatment of lignocellulosic biomass. Despite the considerable promise of this low-input, environmentally-friendly pretreatment strategy, its large-scale application is still limited. Therefore, understanding the best combination of factors which affect biological pretreatment and its impact on enzymatic hydrolysis is essential for its commercialization. The present study was conducted to evaluate the impact of fungal pretreatment on the enzymatic digestibility of switchgrass under solid-state fermentation (SSF) using Phanerochaete chrysosporium (PC), Trametes versicolor 52J (Tv 52J), and a mutant strain of Trametes versicolor that is cellobiose dehydrogenase-deficient (Tv m4D). Response surface methodology and analysis of variance (ANOVA) were employed to ascertain the optimum pretreatment conditions and the effects of pretreatment factors on delignification, cellulose loss, and total available carbohydrate (TAC). Pretreatment with Tv m4D gave the highest TAC (73.4%), while the highest delignification (23.6%) was observed in the PC-treated sample. Fermentation temperature significantly affected the response variables for the wild-type fungal strains, while fermentation time was the main significant factor for Tv m4D. The result of enzymatic hydrolysis with fungus-treated switchgrass at optimum pretreatment conditions showed that pretreatment with the white-rot fungi enhanced enzymatic digestibility with wild-type T. versicolor (52J)-treated switchgrass, yielding approximately 64.9% and 74% more total reducing sugar before and after densification, respectively, than the untreated switchgrass sample. Pretreatment using PC and Tv 52J at low severity positively contributed to enzymatic digestibility but resulted in switchgrass pellets with low unit density and tensile strength compared to the pellets from the untreated switchgrass.

Impact of Elevated CO2 on Leaf Gas Exchange, Carbohydrates and Secondary Metabolites Accumulation in Labisia pumila Benth

Aims: The aim of this study was to investigate different levels of CO 2 availability alters total phenolic and flavonoid, total available carbohydrate (TAC) and to determine how elevated CO 2 influences gas exchange of Labisia pumila seedlings. Study Design: The 3-months Labisia pumila seedlings of var Alata, var Pumila and var Lanceolata were put under 1 month to acclimatize in a nursery until ready for the treatment. Carbon dioxide enrichment treatments started when seedlings reached 4 months old by exposing them to three levels of CO 2 , viz., ambient CO 2 (400 µmol/mol), twice ambient (800 µmol/mol) and thrice ambient CO 2 (1200 µmol/mol). The split plot 3 x 3 factorial experiment was designed using randomized complete block design with CO 2 levels being the main plot and varieties as the sub-plot replicated Original Research Article Ibrahim et al.; ARRB, 19(6): 1-16, 2017; Article no.ARRB.36673 2 three times. Place and Duration of Study: Ladang 2, Universiti Putra Malaysia Glasshouse complex between July to November 2011. Methodology: The experiment was conducted for 15 weeks. The measurement of photosynthesis was obtained from a closed infra-red gas analyzer LICOR 6400XT Portable Photosynthesis System (IRGA, Licor Inc., USA). Total phenolics and flavonoid were determined using Follin-Ciocalteau reagent and total available carbohydrate using anthrone reagent. Results: It was found that the treatment effects were contributed by CO 2 levels in all weeks measured in leaf gas exchange properties (Net photosynthesis (A), stomatal conductance (g s), transpiration rate (E), intercellular CO 2 (C i) and Instantaneous water use efficiency, WUE). A combination of increases rates of A and E was responsible for enhancement of WUE by 50% in elevated treatment (800 and 1200 µmol/mol). Total available carbohydrate, total phenolics and flavonoid were also influenced by elevated CO 2 in all weeks of measurement. At end of 15 weeks after treatment (WAT), 44% increase in total available carbohydrate had increased total phenolic and flavonoid by 56% and 149% respectively than ambient treatment. At end of 15 WAT It was found, that the photosynthetic capacity of Labisia pumila was enhanced under elevated CO 2 by significantly have higher maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings. Conclusion: In this work, it was observed that the increase in production of total phenolics and flavonoid in L. pumila might be due to increase in production of total available carbohydrate in the present study. The upregulation of photosynthesis in the present study was supported by enhancement of Maximum electron transfer rate, J max and Rubisco CO 2 fixation capacity V cmax than ambient seedlings that showed this plant has high sink strength to cope with high level of CO 2.

Management of the noxious weed; Medicago polymorpha L. via allelopathy of some medicinal plants from Taif region, Saudi Arabia.

Germination bioassay was carried out to test the biological activity of Achillea santolina L. (ASAE), Artemisia monosperma Del. (AMAE), Pituranthus tortuosus L. (PTAE) and Thymus capitatus L. (TCAE) aqueous extracts (collected from Taif region, KSA) on germination percentage (GP), plumule (PL) and radicle (RL) lengths (mm) besides seedling dry weight (SDW) (mg/seedlings) of Medicago polymorpha L. The inhibitory effect of P. tortuosus was insignificant compared to the other three donor species which attained the strongest allelopathic potential in the following order: A. santolina > A. monosperma > T. capitatus. Growth experiment using crude powder of the four donor species was conducted to examine their effects on leaf area index (LAI), photosynthetic pigments, total available carbohydrates (TAC) and total protein (TP). It is worth mentioning that each of the four donor species crude powders mixed with clay loam soil appeared to have a great inhibitory allelopathic effect on LAI, total photosynthetic pigment and chlorophyll a (Chl a) while carotenoids exhibited a slight increase with the application of the four donor species crude powders. TAC and TP were significantly decreased with increasing the crude powder concentrations while a slight decrease was recorded for carbon/nitrogen (C/N) ratio. There is possibility of using these allelochemicals directly or as structural leads for the discovery and development of environmentally friendly herbicides to control weeds. The study recommended that these species must be phytochemically examined in future for their allelochemicals in order to provide information on the possibilities of using one or more of these species as bioherbicides.

Effect of Addition of Three Leaf Yam Flour on Dough Properties and Sensory Qualities of Bread

<p>The effect of three leaf yam flour addition at 5%, 10% and 15% substitution level, dough properties, proximate analysis and sensory qualities of bread were investigated. The values for moisture content ranged from 25.2% to 29.5% with sample A (100%WF) significantly different (p <span style="text-decoration: underline;"><</span>0.05) from all the other samples. Protein and fat contents ranged from 11.9% to 13.00% and from 1.46% to 4.67% with sample D (15%TLYF) significantly different (p <span style="text-decoration: underline;"><</span>0.05) from the other samples. Ash and fibre contents ranged from 0.64 to 1.11% and 0.90 to 5.40%, respectively. Total Available Carbohydrate (TAC) ranged from 48.82% to 59.78% with sample D (15%TLYF) been significantly different (P<span style="text-decoration: underline;"><</span>0.05) from the other samples. Result for physical characteristics showed that volume of bread samples ranged from 157.45cm<sup>3</sup> to 158.6cm<sup>3</sup> with sample F (10%CF) the least and sample A (100%WF) the highest while weight ranged from 340.04g to 412.66g with sample B the lowest and sample G the highest. Sensory evaluation result for bread showed that samples A (100% WF, B (5%TLYF), E(5%CF) and F(10%CF) were most preferred for crust color, taste, texture and overall acceptability. Alveograph studies of bread dough gave work done (W) ranging from 126 to 307 with 15% cassava flour as the lowest and 100% Wheat flour the highest, while extensibility ratio of dough ranged from 41-76 with sample C (10%TLYF) as the least and (10%CF) as the highest. Work done and extensibility results of bread dough decreased with an increase in substitution level, while ratio of resistance to extensibility (P/L) increase with an increase in substitution for three leaf yam composite dough. The presence of three leaf yam flour addition improved the nutritional qualities of the bread in terms of protein, fat and ash while carbohydrate content reduced which is to an advantage, while addition affected the sensory and physical properties adversely.</p>

The Functional Properties of Starches, Physico-Chemical and Sensory Properties of Salad Cream from Cassava and Potatoes

The Physicochemical, sensory properties and viscosity of salad cream stabilizes with cassava and potato starches were investigated, with commercial salad cream used as control. Cassava and potato starches were processed using standard methods. The functional properties of cassava and potato starches showed that dispersibility were 84-86%, swelling power were 6.20-8.19% and solubility were 13-14% with no significant difference (p>0.05) between the starches. Although water and oil absorption capacities were 19.7-27.7% and 9.20-11.30% respectively. Water and oil absorption capacities showed a significant difference (p<0.05) between the starches. Chemical analysis results showed that moisture content were 57.84-64.88%, dry matter were 42.16-54.69%, starch content were 6.40-14.41% and total available carbohydrate (TAC) ranged from 7.11-17.32% respectively with potato starch based salad cream having the least and the control(commercial salad cream) having the highest. pH, total solids, protein and fats were 3.14-3.50, 35.12-42.16%, 0.23-0.35% and 25.17-28.15% respectively with the control having the lowest value and potato based salad cream having the highest. Total Titratable Acidity (TTA) had potato based salad cream as the lowest (0.02) and cassava based salad cream as the highest (0.89), while ash had (1.62%) as the lowest for cassava starch based salad cream and (1.83%) as the highest for the control. Moisture, dry matter, total solid, starch, fat and total available carbohydrate showed a significant difference (p<0.05) amongst the samples while total acidity, pH, protein and ash showed no significant difference (p>0.05). Sensory analysis result showed that color were 3.36-4.24, taste were 2.54-3.88 and spreadability were 3.52-4.36 with the three parameters showing a significant difference (p<0.05) amongst the samples, while odour, texture and general acceptability showed no significant difference (p>0.05) and were 3.44-3.76, 3.56-3.96 and 3.80- 3.88 respectively. The viscosity result of the salad cream samples showed that potato based salad cream had the highest viscosity at varying speeds of 6, 12, 30 and 60rpm followed by the control and cassava based salad cream. All salad cream samples exhibited a non Newtonian behaviour.

THE EFFECT OF PREHARVEST TREATMENT, DISINFECTION AND STORAGE ENVIRONMENT ON QUALITY OF CARROTS

ABSTRACT The physiological, microbiological and chemical quality changes were studied in carrots that received preharvest sprays of a commercial plant extract (ComCat) and subjected to disinfection and storage at 1 and 22C. At harvest, ComCat-treated carrots had less aerobic and coliform bacteria population, higher contents of total available carbohydrates (TACs) and sucrose and lower glucose and fructose concentrations. During storage, ComCat-treated carrots displayed reduced physiological weight loss (PWL) with lower sucrose, glucose and fructose concentrations. Disinfectants reduced microbial populations in carrots. Chlorine disinfection resulted in an etched surface, which was not observed for anolyte treatment. Anolyte water showed a better positive effect on PWL. Higher temperatures deteriorated quality characteristics of carrots. The TAC accumulated better in ComCat-treated than in control carrots stored at room temperature. The combined effect of pre- and postharvest treatments had significant effect on maintaining postharvest quality and improvement of shelf life of carrots. PRACTICAL APPLICATIONS Preharvest ComCat treatment can be used to improve the overall quality of carrots. Disinfection of carrots using anolyte water was found to be superior to the chlorinated water dipping treatments. Thus, anolyte water is recommended for disinfection of carrots. Combining the preharvest ComCat treatment and disinfection using anolyte water, coupled with refrigerated storage environment should be used in the shelf life extension of carrots.

Carbohydrate composition of raw and extruded pulse flours

Extrusion cooking technology is commercially used in the fabrication of a variety of snack-type and ready-to-eat foods made from cereal grains. However, with the exception of soybean, pulses such as lentil, dry pea and chickpea have not been used for the development of extruded food products. In this study, total carbohydrates, mono-, di- and oligosaccharides, and soluble and insoluble dietary fiber were determined before and after extrusion cooking under specific processing conditions. Concentrations of total available carbohydrates (TAC) in lentil, chickpea and dry pea flours ranged from 625 g/kg to 657 g/kg dry matter. Dry pea showed the highest concentration of TAC, followed by chickpea and lentil. Extrusion processing did not significantly (p < 0.05) affect the TAC content of dry pea and lentil flours. However, extrusion processing decreased the concentration of the raffinose family of oligosaccharides (raffinose and stachyose) in pulse extrudates. Formulated pulse flours demonstrated a beneficial increase in dietary fiber. This research indicates that value-added, nutritious snacks with reduced levels of flatulence factors and higher contents of dietary fiber can be fabricated successfully by extrusion processing of formulations based on lentil, dry pea or chickpea, and represent good alternatives to traditional cereal-based snacks. Also, the commercialization of value-added, pulse-based snacks would increase pulse consumption.

Quantitative Estimation of Physiological Functions of Various Roots with Different Diameters in the Root System of the Tea Tree.

The root system of the tea (Camellia sinensis L.) tree consists of various types of roots with different diameters or ages. In order to control the growth of the root system, it is necessary to know the physiological functions of various types of roots within a root system quantitatively. Tea trees, two years after transplanting, were dug out from the field at the bud break stage of the first flush, then the roots were classified into four groups according to their diameter. Top/root ratio of the examined trees was around 1.5. Dry weight ratios of white rootlet (diameter 5.0mm) in root systems were 30%, 10%, 15% and 45%, respectively. Rates of respiration and nitrogen uptake per unit dry weight were higher in the younger rootlets, while the content of total available carbohydrate (TAC) was higher in the lignified thick roots. Quantitatively, 75% of the respiration and 90% of nitrogen uptake in the root system was conducted by the rootlets less than 2.0mm in diameter. Contribution of the white rootlets to the total nutrient uptake of the root system was especially large. On the other hand, 84% of TAC in the root system was localized in thc lignified roots more than 2.0mm in diameter. A higher level of theanine, a main palatable substance of tea, was detected in the white rootlet as compared to the lignified roots, indicating that the synthesis of this substance occurred in the newly developing roots. In the lignified roots, a large amount of arginine accumulated instead of theanine. From these results, ideotype of the root system in the tea tree was considered to be different according to the purpose of tea cultivation. A root system with higher proportion of rootlets would be desirable for increasing the yield and quality of the leaves. On the contrary, existence of well-developed lignified roots would be necessary for tolerating environmental stresses.

Studies on growth and functions of root system in tea plants. V Changes in carbohydrate, amino acid and nitrogen contents during the process of root regeneration after root pruning.

This experiment was conducted to clarify the relation between the process of root regeneration and changes in some chemical components in root-pruned teaplants (Camellia sinensis (L.) O. Kuntze cv. Yabukita). The growth of top and roots, and TAC (total available carbohydrate), total amino acid and nitrogen contents were investigated over about six-month period after the root pruning. About a half of root of one-year old plants were pruned in early September 1983 (Fig. 1). The top growth was prominently retarded by the pruning. The weight of top (including the mother stem) in the pruned plants was reduced to nearly 75% of that in the intact plants (Table 1). In contrast, the root growth was activated after the pruning. The weight of roots was markedly increased. especially in wite roots. At the 36th day after the pruning. the root of the pruned plants rather exceeded in weight that of the intact plants. The remarkable increase in the white roots on the mother stem was recognized within 36 days succeeding the pruning, while that on lignified roots required one month after the pruning. The percentage of the white roots in the treated plants was around 10% higher than that in the intact plants. Although the T/R ratio of the treated plants had been considerably raised due to the pruning, it returned to approximately the same level as that of the intact plants at the 26th day (Table 2). The pruning not only raised the TAC content, but the partition of the TAC to the mother stem and roots greatly increased (Figs. 3, 4). Furthermore, the pruning increased the partition of nitrogen to the mother stem and roots, in spite of a deterioration in content (Figs. 5, 6). The amino acid content in the treated plants showed a lower level as compared with that in the intact plants. The amino acid content of lignified roots greatly decreased following vigorous regeneration of roots (Fig. 7). The distribution of the TAC and nitrogen in the treated plants, however, approximately accorded with these in the intact plants after 187 days. The above results suggest that the root regeneration after the pruning in tea plants rapidly proceeds through active growth of white roots exceeding the growth in the intact plants. The translocation of some chemical components to under-ground parts and the accumulation there that were induced by the root pruning were considered to closely concern with the root regeneration. The retardent of the top growth following the root pruning was estimated to be induced by the translocation of substances to roots and vigorous regeneration of roots. To promote the root regeneration after the root pruning, treatments that maintain a proper level of hormons and relieve the deficit of photosynthate and nitrogen are necessary.

Fall Cutting of Alfalfa in the North Central USA1

AbstractThe North Central (NC) and Northeast (NE) states produce almost two‐thirds of the alfalfa (Medicago sativaL.) in the USA. Three cuttings by early September is the most popular management system. A third cutting in mid‐September to early October has been considered deleterious to subsequent yield and persistence compared with cutting in late August or early September. Our objective was to determine the effects of the final cutting date on subsequent yields and persistence of fertilized and unfertilized hardy and moderately hardy cultivars in a three‐cut system in southern Michigan. Hardy (‘Vernal’ and ‘Cayuga’) and moderately hardy (‘DuPuits’, ‘Saranac’, and ‘Honeoye’) alfalfa cultivars were used in four separate experiments on well‐drained Conover loam (fine‐loamy, mixed mesic Udollic Ochraqualfs). Third cuttings made on 15 September or 1 or 15 October for three consecutive years did not reduce the subsequent year's yield or persistence compared with the control cutting date of 1 September if the cultivar was resistant to bacterial wilt [Corynebacterium insidiosum(McCull) H.L. Jens] and fertilized with K. Yields were reduced if the cultivar was wilt‐susceptible and was cut on 15 September. Levels of total available carbohydrates (TAC) followed similar bi‐monthly trends between 6 September and 13 December for both cultivars. Average TAC content of the two cultivars increased to 304 g kg−1on 1 November and then decreased to 271 g kg−1on 13 December when alfalfa was dormant. On 13 December, levels of TAC were the same within cultivars for all fall cutting treatments and lower for DuPuits than for Vernal. Yields and persistence were not reduced by variable dates of fall cutting after a second cutting in mid‐July if the cultivar was wilt‐resistant, hardy or moderately hardy, and the soil had been well fertilized with K. The present recommendation of not cutting in September and early October or 4 to 6 weeks before the first killing frost in the NC and NE states should be reevaluated.

Deterioration of Alfalfa Swards in the Hot Humid Subtropics of India1

AbstractAlfalfa (Medicago sativa L.) planted in the humid subtropics of India has not persisted well. To determine the effects of management practices on persistence and production, herbage growth, plant populations, Fusarium incidence on roots, and total available carbohydrates (TAC) were determined.Seven P and K fertilizer regimes and two cutting frequencies were used with ‘Anand—2’ and ‘Sirsa‐9’ alfalfa cultivars sown in the fall of 1975, 1976,. and 1977 on an Antisol soil in the subtropical plains of the eastern region in India.In 1976‐1977 and in 1977‐1978, Sirsa—9 yielded 7.6 and 9.7 metric tons/ha, respectively, while Anand—2 produced 6.9 and 8.3 metric tons/ha, of dry matter, respectively. Major fertilizer yield response was almost linear for 0, 22, and 44 kgha of P. Response to K was minimal and only after plant P needs were satisfied. Response to P was greater in 1977‐1978,Plant populations decreased consistently during the summer to about zero in October 1976 and August 1977, while in 1978 in a better drained area plant populations in July reduced from 70 to 30%.Root weights decreased drastically from 172 days after sowing (DAS) to 263 DAS regardless of management factor in the first two seasons. Fusarium root rot incidence by 203 DAS was severe for all management treatments except for one K treatment. No relationship between incidence and herbage yield was evident, however. Plant density and disease seventy was positively correlated (r = 0.97). Total available carbohydrate concentrations decreased, also, from about 35 at 172 DAS to 18% at 263 DAS. A positive correlation of r = 0.74 was found between disease severity and TAC.Additional work is needed to delineate the effects of Fusarium, and soil and plant factors before alfalfa could be recommended as a perennial in the subtropical regions representative of the experimental area.

Growth and Development of Potato Plants Influenced by Combinations of Air-and Soil-Temperatures

Using phytotrons with natural light, several day air-temperatures (night air-temperatures were 5°C lower than the respective day air-temperatures) were combined with the three soil-temperatures as shown in Table 5, to investigate the combined effects of air-and soil-temperatures on the growth and tuber production of the potato plants. The first treatment was given from juvenile to tuber formation stages for 23 days and the second treatment during bulking stage for 30 days. The results are summarized as follows : 1. The plant height was greatest at 24°C air-temperature (mean daily temperature; 21.5°C) combined with 30° soil-temperature; i.e. 24°-30°. Before tuberization occurred, the dry weight of whole plant almost parallelled plant height in response to various temperatures. Tuberization occurred most quickly at 24°-24°, being followed by 17°-17°. Under 30° air-temperature (mean daily temperature; 27°) tuberization was inhibited but slightly occurred when soil-temperature was lowered. At bulking stage, 17° air-temperature (mean daily temperature; 14.5°) was most favorable for tuber growth, and tuber yield was highest at 17°-17°, being followed by 24°-24°. 2. The dry matter and nitrogen distribution in leaf before tuberization were increased with decrease of air-temperature reaching more than 50% of whole plant. At bulking stage, however, they decreased at all organs except tubers with decrease of air-temperature due to their higher distributions at tubers. Under these situations, dry matter, total available carbohydrate (TAC) and total nitrogen or crude protein (CP) distributions at stem markedly decreased. 3. Leaf/stem in terms of dry matter and nitrogen accumulations increased with decrease of temperature, and tended to increase at soil-temperatures that promoted tuber growth. 4. Nitrogen concentrations and soluble-N/protein-N in leaf at bulking stage tended to decrease, while TAC concentrations, TAC/CP increased with decrase of air-temperatures. Stem and roots showed the almost similar responses. It was observed that soluble-N/protein-N in stem was especially higher as compared to other organs. In stem, CP concentrations were high under high air-temperature and low at the soil temperatures favorable for tuber growth, while TAC concentrations, sugar/starch, and TAC/CP increased with decrease of air-temperature, the latter being distinctly high at soil temperatures favorable for tuber growth. 5. The thickness of leaf blade and the length of palisade cells increased, while the pallisade cell density decreased with decrease of air-temperature. 6. RGR had a strong positive correlation with NAR, both being higher at the conditions favorable for tuber growth with a higher distribution of dry matter to it. NAR showed a positive correlation with length and volume of pallisade cell, but a negative correlation with its density, and showed positive correlations with root efficiency. 7. In the temperature regimes of this experiment, tuber yield showed a negative correlation with the mean air-soil temperatures (air+soil/2 temperatures), and the highest yield was obtained at 24°-24°, 17°-17°, sllowing a possibility that soil temperature too should change diurnally. It was suggested that the temperature conditions most favorable for tuber growth increased the matter in tubers, root efficiencies, NAR and leaf/stem ratio, resulting in the highest dry matter production of whole plant.

The Growth Responses of Soybean Plant to Photoperiod and Temperature : IV. The effect of temperature during the ripening period on the yield and characters of seeds

The effect of temperature during the ripening period on the seed yield and its quality was investigated using cv. Miyagishirome. The temperature treatments were composed of eight plots: five day/night temperature plots (30°/25°, 30°/20°, 25°/20°, 25°/15° and 17°/12°C, day and night temperatures being constant, respectively), two gradual temperature change plots (the diurnal temperature gradually changes along with sine curves designated as 25°/20°and 17°/12°, the daily mean temperature being almost the same to the respective 25°/20° and 17°/12° plot) and outdoor control (average daily mean temperature was about 21°C). The results obtained are summarized as follows: 1. The dry weight per plant was in the following orders: 25°/20°>30°/25°≥17°/12° in case of 5°C daily range, and 25°/15°>30°/20° in case of 10°C daily range. When the day temperature was the same, the dry weight per plant grown under 10°C lower nights was greater than that under 5°C lower nights. There was little difference in dry matter production between the gradual temperature change plots and the suddenly change plots. The dry weight of the outdoor control was almost the same as that of 25°/20°. 2. Seed yield per plant was greater at 25°/15° and 30°/20° plots, followed by 25°/20°, 25°/20°, 30°/25° and outdoors in that order, and very small both at 17°/12° and 17°/12°. Numbers of pod and seed per plant tended to increase with increase of temperature in case of 5°C daily range, while those of 25°/15° and 30°/20° were almost same. Numbers of pod and seed of 10°C daily range were greater than those of 5°C daily range when the day temperatures were same, and those of the outdoor control were similar to those of 25°/20°. 100-seed weight was very great at 25°/20° and 25°/20°, followed by 25°/15°, 30°/20°, outdoor control, 30°/25° in that order and those of 17°/12°, 17°/12° were extremely small. 3. N, K, TAC (Total Available Carbohydrate) and seed oil accumulation perplant were paralleled with dry matter accumulation in response to temperature. P accumulation tended to increase with increase of temperature. At maturity most of N, P, K and TAC accumulated in seeds, Mg+Ca in pod shells and Fe and Na in roots, respectively. The concentration of Fe and oil in seeds tended to increase and that of carbohydrate to decrease with increase of temperature. Saturated fatty acids in seed oil such as palmitic, stearic and oleic acid with one double bond tended to increase and other unsaturated acids such as linoleic and linolenic to decrease with increase of temperature. 4. The larger seeds ripened outdoors or at 25°/20°, 25°/15° and 30°/20° showed a higher germination percentage. 5. In the regime of this experiment, day temperature of 25° to 30° with 10°C daily range during the ripening period seemed to be optimum for dry matter accumulation, nutrient absorption, seed yield, and seed characters, suggesting that the optimum temperature for ripening is a ittle lower than that for vegetative growth.

The Cost of Being Dormant in the Tropics

The roots, stems, and twigs of Jacquinia ptangens were found to lose as much as one-half of their stored carbohydrate reserves when leafless during the rainy season. This finding implies that dormancy can be an expensive way to avoid an inimical environment. Jacquinia pungens A. Gray (Theophrastaceae) is an understory shrubby tree in Central American deciduous forests. In Costa Rica, it produces leaves at the beginning of the dry season (December) and drops them about six months later at the beginning of the rainy season (May-June) (Janzen 1970). In this paper we examine the hypothesis that the rainy (dormant) season is a period of substantial stress to the plant, as measured by metabolic expenditures at this time. The cost to J. pungens of rainy season dormancy is a special case of the general problem of understanding the cost of being dormant at high tropical temperatures. This dormancy contrasts strikingly with the apparent low metabolic cost of dormancy for a poikilothermic tree during the cold season in temperate zones. We chose J. pungens for this study because of its abundance, small size at reproductive maturity, conspicuous starch storage, lack of sexual activity while leafless, and potential for suggesting minimal maintenance costs for a woody plant during the rainy (coolest) time of year in the lowland tropics. METHODS AND STUDY AREA Twig, main stem, and root segments were collected from each of five 1.5-2.0 m tall J. pungens shrubs on seven dates (table 1). Twig segments were from the previous year's growth; main stem segments were 2-4 cm diameter and from about 30 to 80 cm up the trunk; and the root segments were from the tap root at a point 10-20 cm below the ground and the same diameter as the main stem segments. J. pungens is exceptional among tropical deciduous forest understory shrubs in that it has a very deep and large tap root (Janzen 1970). The shrubs were sacrificed when sampled. The woody segments (including the thin bark) TABLE 1. Total available carbohydrate (TAC) in mg per g of Jacquinia pungens twig, stem and root segments. Each value is the average of five samples and the same five shrubs were used for twig, stern and root segments on a given date. See text for calculation of TAC for entire shrub.

High Temperature Injury of ripening in rice plant : I. The effects of high temperature Treatments as different stages of panicle development on the ripening

A japanica rice (var, Norin-17) was used to test the effects of high temperature treatment (day-night, 35-30°C) from young panicle formation to maturity upon the ripening and the distribution of assimilates, and upon the pollens and anthers. 1) More than 20 per cent sterility occurred when treated just before and after flowering, being progressively decreased as the time of treatment was apart from flowering stage. In general, a larger amount of carbohydrate and nitrogen remained in the straw of the plant which exhibited a higher sterility. The plant with the greatest sterility treated at flowering stage produced grains of the greatest 1000-kernel-weight, being greater than the control. 2) The pollens of plants treated just before and during were smaller in size and stored starch abnormally, often being deficient of inclusions. Besides, the plants had a greater number of anthers which did not open at flowering. These may be related to the high sterility. 3) The plants treated at one or two weeks before flowering produced grains of smaller 1000-kernel-weight, due to smaller grain size especially in its length, although the sterility did not increase by the treatment. In such a plant, more nitrogen and available carbohydrate remained in the straw than the control plant. 4) The grains of plant which was treated under high temperature at several stages during the ripening period decreased in weight, but their sterility did not increase. Grain weight was smallest in the plant treated at 6 to 16 days flowering stage, mainly due to a decrease in grain thickness, and became progressively greater as the time of treatment went away from those period. The sum of TAC(total available carbohydrate)content of panicle and straw was decreased by the high temperature treatment, but more of it remained in the straw of the plants with smaller grains. Nitrogen accumulation did not change significantly by the treatments.

High Temperature Injury of Ripening in Rice Plant : II. Ripening of rice grains when the panicle and straw were separately treated under different temperature

A japanica rice (var, Norin-17) and two indica rice (var, IR-8 and Boshito) were used to test the effects of temperature treatment separately given to the panicle and the straw including roots upon the ripening and the distribution of assimilates to the both parts. The plots of treatments are indicated as follows: 35/35, 30/35, 35/30, 30/30, 25/25, 20/25, 25/20, 20/20 in 1969 and 35/35, 25/35, 35/25, 25/25°C in 1970. The numerator indicates day-air-temperature around the panicle, and the denominator around the straw, respectively. The night-temperature is 5°C lower than the respective day-temperature. 1) In the three varieties, 1000-kernel-weight was markedly decreased by high panicle temperature (35°C), but increased by near optimum panicle temperature (20-25°C). Lowering of temperature around the straw was also effective, but not so significant in improving 1000-kernel-weight. The kernels ripened under high panicle temperature became inferior in quality with least normal, but much opaque, chalky, and milky-white kernels. 2) Sol.-N/Prot.-N ratio in the straw was increased when both panicle and straw or straw only were treated at high temperature. The total sugar concentrations and total-surgar/ crude-starch ratios in both panicle and straw were also increased by treating the panicle or straw or both by high temperature, suggesting some physiological abnormality occurred in the plant. 3) The amount of TAC (total available carbohydrate) stored per tiller was greatest at 25/25, being followed in order by 35/25, 25/35, 35/35. Relatively more TAC was translocated and stored in the panicle with the less amount remained in the straw, when the panicle was treated with lower temperature. On the contrary, the total nitrogen accumulation per tiller was greater under higher temperature, greatest at 35/35, being followed by 25/35, 35/25, 25/25 in order. However, when the temperature around panicle was lowered relatively more nitrogen accumulated in the panicle, resulting in less nitrogen in the straw. The high nitrogen accumulation under high temperature was partly caused by new tillers with new roots emerged from higher nodes after about two weeks of treatment. 4) The leading factor which decreased 1000-kernel-weight under high air-temperature was considered to be an early cease of the receiving function of panicle of assimilates from the straw, although the temperature around straw was also effective in changing 1000O-kernel-weight.

Carbohydrate Reserves of Crested Wheatgrass and Russian Wildrye as Influenced by Development and Defoliation

Carbohydrate reserves of crested wheatgrass (Agropyron cristatum) and Russian wildrye (Elymus junceus) were lowest after initial spring growth, but maximum levels were rapidly attained as plants approached maturity. Fall regrowth caused reductions in total available carbohydrate (TAC) stores. More TAC reserves were used to produce new growth if plants were defoliated during spring growth than if defoliated at maturity or quiescence. Autumn TAC storage levels in both crested wheatgrass and Russian wildrye were reduced by all previous defoliations. Autumn reserve storage was directly related to the amount of new growth produced after defoliation. Results indicate that both crested wheatgrass and Russian wildrye are adapted for either fall or early spring grazing and under some circumstances for spring-fall use. Defoliation when plants are rapidly replenishing reserves or before maturity reduces subsequent new growth and carbohydrate reserve stores in the autumn.

Comparison of Male Sterile and Male Fertile Corn for Silage1

AbstractA comparison of male sterile and male fertile corn (Zea mays L.) for dry matter production, total available carbohydrates (TAC), silage digestibility, and volatile fatty acid (VFA) production from the silage during rumen dermentation was made at Experiment, Georgia in 1968 to 1969. Dry forage yields were similar for the male literile and male fertile corn in 1968, but the male sterile vielded more than the male fertile in 1969. The male fertile hybrid contained a higher percentage TAC than did the male sterile hybrid. There were no significant percentage differences between the silages in individual VFA production, or digestibility of dry matter, crude protein, crude fiber, cellulose, ether extract, and nitrogen iree extract. The data indicate that at the maturity studied male sterile corn plants (without kernel development) are comparable to male fertile corn plants (with kernel development) for making silage.

Quality and Yield of Corn Plants and Component Parts when Harvested for Silage at Different Maturity Stages1

AbstractThe influence of maturity and rainfall distribution on quality of component parts (ear, leaf, and stalk) and whole plants of corn (Zea mays, L.) harvested as silage was studied over a 3‐year period at Experiment, Georgia. Seven harvests were made at weekly intervals from the late milk to mature stage of the grain. In vitro dry matter digestibility (IVDMD) and total available carbohydrate (TAC) content of ears increased with maturity then leveled off, and IVDMD reached a maximum later (dough stage) than did carbohydrate content (early dough stage). The time of maximum ear IVDMD was delayed when adequate rainfall was received during the harvest period. Leaf IVDMD and TAC content generally decreased with maturity. Both IVDMD and TAC content of the stalks were closely related to the rainfall received during the maturing period, decreasing with maturity when rainfall was limited, increasing when rainfall was received after a drought period, or remaining constant when rainfall was well distributed. The changes noted in ear and stalk quality were reflected in whole plant quality. Green forage yields generally decreased with maturity, but when adequate rainfall was received before the dough stage this decrease was delayed. Dry forage yields increased until the fourth harvest then decreased with maturity. Ear content increased until the dough stage then leveled off, while stalk content decreased to this stage then leveled off. Leaf content generally decreased with maturity.

Organic Reserves, Axillary Bud Activity, and Herbage Yields of Smooth Bromegrass as Influenced by Time of Cutting, Nitrogen Fertilization, and Shading1

Smooth bromegrass (Bromus inermis Leyss.) was sampled at eight stages of spring growth for percentages of total available carbohydrates (TAC) and total N in the storage organs, weight of storage organs, number of tillers per plant, and number and activity of tillers developed in vitro by basal axillary buds. Results were compared with regrowth produced 7 weeks after each spring harvest under treatments of N fertilizer, shading, and association with alfalfa.Percentage TAC, weight of storage organs, and activity of the basal axillary buds generally increased as bromegrass advanced from young tillering to late maturity stages of growth. Percentage total N in storage organs was highest in young tillering plants, declined until the plants headed, and then increased. Tiller numbers per plant decreased from young tillering to headed growth stages and then remained constant. Number of active axillary buds on bromegrass declined until plants headed and then increased.Percentage TAC, weight of storage organs, and number of tillers per plant at the time of the spring harvests had little association with the amount of regrowth produced after 7 weeks. Number of axillary buds and their activity were more closely associated with regrowth, and total N concentration in the storage organs and regrowth were positively correlated under all treatments.