Decline In Dry Weight Research Articles

Anthracnose Disease and Physiological Aspects of Soybean in Saturated Soil Culture in Tidal Land

Saturated soil culture in tidal land could be an alternative measure for achieving sufficient soybean production to meet demand and reduce the current 56% dependence on imports. Therefore, this study aims to investigate disease development and the nitrogen fixation rate of soybean in water-saturated cultivation on tidal land. It was conducted in Simpang Village, Berbak District, East Tanjung Jabung, Jambi Province, Indonesia, and subjected to a randomized block design as an environmental design. The treatment consisted of 3 water inundation levels in the trench, namely, 15, 20, and 25 cm from the soil surface. The results showed that the height of standing water in a water-saturated cultivation system affected the soil moisture. Furthermore, high soil moisture results in a high anthracnose disease in soybean caused by the fungus Colletotrichumdematinum var. truncatum. The disease attack rate reached 15.7% with 72% soil moisture at a depth of 15 cm below the soil surface. There was also an attack rate of 16.3%, with soil moisture of 70.5% at a depth of 20 cm from the soil surface. The highest percentage of fallen pods in the treatment plots was up to 15cm and 20 cm in standing water, which was 17.3% and 16.7%, respectively. The root nodules' weight decreased in height by 25 cm from the soil surface. Furthermore, the rate of nitrogen fixation decreased, as indicated by a reduction in the activity of the root nodules' acetylene, which decreased at the height of the waterlogging 25 cm from the soil surface. Soybean crop yield was affected by the height of standing water in the trench. The numbers of filled pods, the weight of dry seeds per plant, and the weight of 100 seeds were lower at the height of water 25 cm from the soil surface. Additionally, disease severity was strongly correlated with root nodules and seed/plant dry weight. Increased disease severity significantly contributed to the decline in dry weight of root nodules, very strongly to dry seed/plant weight and moderately to acetylene-reducing activity.

Heterogeneous Light Conditions Reduce the Assimilate Translocation Towards Maize Ears.

The border row crop in strip intercropped maize is often exposed to heterogeneous light conditions, resulting in increased photosynthesis and yield decreased. Previous studies have focused on photosynthetic productivity, whereas carbon allocation could also be one of the major causes of decreased yield. However, carbon distribution remains unclear in partially shaded conditions. In the present study, we applied heterogeneous light conditions (T), and one side of plants was shaded (T-30%), keeping the other side fully exposed to light (T-100%), as compared to control plants that were exposed entirely to full-light (CK). Dry weight, carbon assimilation, 13C abundance, and transport tissue structure were analyzed to clarify the carbon distribution in partial shading of plants. T caused a marked decline in dry weight and harvest index (HI), whereas dry weight in unshaded and shaded leaves did not differ. Net photosynthesis rate (Pn), the activity of sucrose phosphate synthase enzymes (SPS), and sucrose concentration increased in unshaded leaves. Appropriately, 5.7% of the 13C from unshaded leaves was transferred to shaded leaves. Furthermore, plasmodesma density in the unshaded (T-100%) and shaded (T-30%) leaves in T was not significantly different but was lower than that of CK. Similarly, the vascular bundle total area of T was decreased. 13C transfer from unshaded leaves to ear in T was decreased by 18.0% compared with that in CK. Moreover, 13C and sucrose concentration of stem in T were higher than those in CK. Our results suggested that, under heterogeneous light, shaded leaves as a sink imported the carbohydrates from the unshaded leaves. Ear and shaded leaf competed for carbohydrates, and were not conducive to tissue structure of sucrose transport, resulting in a decrease in the carbon proportion in the ear, harvest index, and ear weight.

Roots and Nodules Response Differently to P Starvation in the Mediterranean-Type Legume Virgilia divaricata.

Virgilia divaricata is a tree legume that grows in the Cape Floristic Region (CFA) in poor nutrient soils. A comparison between high and low phosphate growth conditions between roots and nodules was conducted and evaluated for the plants ability to cope under low phosphate stress conditions in V. divaricata. We proved that the plant copes with low phosphate stress through an increased allocation of resources, reliance on BNF and enhanced enzyme activity, especially PEPC. Nodules had a lower percentage decline in P compared to roots to uphold its metabolic functions. These strategies partly explain how V. divaricata can sustain growth despite LP conditions. Although the number of nodules declined with LP, their biomass remained unchanged in spite of a plant decline in dry weight. This is achieved via the high efficiency of BNF under P stress. During LP, nodules had a lower % decline at 34% compared to the roots at 88%. We attribute this behavior to P conservation strategies in LP nodules that imply an increase in a metabolic bypass that operates at the PEP branch point in glycolysis. The enhanced activities of nodule PEPC, MDH, and ME, whilst PK declines, suggests that under LP conditions an adenylate bypass was in operation either to synthesize more organic acids or to mediate pyruvate via a non-adenylate requiring metabolic route. Both possibilities represent a P-stress adaptation route and this is the first report of its kind for legume trees that are indigenous to low P, acid soils. Although BNF declined by a small percentage during LP, this P conservation was evident in the unchanged BNF efficiency per weight, and the increase in BNF efficiency per mol of P. It appears that legumes that are indigenous to acid soils, may be able to continue their reliance on BNF via increased allocation to nodules and also due to increase their efficiency for BNF on a P basis, owing to P-saving mechanisms such as the organic acid routes.

Combined effect of 24-epibrassinolide and salicylic acid mitigates lead (Pb) toxicity by modulating various metabolites in Brassica juncea L. seedlings.

The present study demonstrated the combined effect of 24-epibrassinolide and salicylic acid against lead (Pb, 0.25, 0.50, and 0.75mM) toxicity in Brassica juncea seedlings. Various parameters including water status, metal uptake, total water- and lipid-soluble antioxidants, metal chelator content (total thiols, protein-bound thiols, and non-protein-bound thiols), phenolic compounds (flavonoids, anthocyanins, and polyphenols), and organic acids were studied in 10-day-old seedlings. Dry matter content and the heavy metal tolerance index were reduced by 42.24 and 52.3%, respectively, in response to Pb treatment. Metal uptake, metal-chelating compounds, phenolic compounds, and organic acids were increased in Pb-treated seedlings as compared to control plants. The treatment of Pb-stressed seedlings with combination of EBL and SA resulted in enhancement of heavy metal tolerance index by 40.07%, water content by 1.84%, and relative water content by 23.45%. The total water- and lipid-soluble antioxidants were enhanced by 21.01 and 2.21%, respectively. In contrast, a significant decline in dry weight, metal uptake, thiol, and polyphenol contents was observed following the application of 24-epibrassinolide and salicylic acid. These observations indicate that Pb treatment has an adverse effect on B. juncea seedlings. However, co-application of 24-epibrassinolide and salicylic acid mitigates the negative effects of Pb, by lowering Pb metal uptake and enhancing the heavy metal tolerance index, water content, relative water content, antioxidative capacities, phenolic content, and organic acid levels.

The effect of extended wet-storage on the condition, physiology and stress response of cultured blue mussels (Mytilus edulis L. 1758) during summer and fall in northeastern Newfoundland

In order to determine the effects of extended wet-storage under ambient conditions we investigated the physiological response of blue mussels held for up to 3months in a commercial holding facility. During the summer and the fall there was a significant decline in dry weight and condition of mussels held over time when compared to field controls. Neutral red retention time decreased significantly in holding for both seasons but not in the field controls, indicating an increase in stress response for held mussels. Little variation was noted in the expression of the oxidative stress genes superoxide dismutase and GSH-peroxidase during the summer or fall regardless of treatment. Expression of the antimicrobial peptide MGD2 was evident in the summer holding samples as early as 1week but did not occur in the fall holding samples until 3months. This suggests that holding conditions have stimulated the immune response in a manner potentially related to time in holding and environmental temperature. Based on our results we recommend that one month should be the maximum time allowable in ambient extended holding during warm water seasons. During the warmest part of the summer this could be reduced to two weeks.

Temporal changes in the growth, saponin content and antioxidant defense in the adventitious roots of Panax ginseng subjected to nitric oxide elicitation

Nitric oxide (NO) is a diffusible, gaseous signaling molecule. In plants, NO influences growth and development, and it can also affect plant responses to various stresses. Because NO induces root differentiation and interacts with reactive oxygen species, we examined the temporal effect of NO elicitation on root growth, saponin accumulation and antioxidant defense responses in the adventitious roots of mountain ginseng (Panax ginseng). The observations revealed that NO is involved in root growth and saponin production. Elicitation with sodium nitroprusside (SNP) activated O2−-generating NADPH oxidase (NOX) activity, which most probably subsequently enhanced growth of adventitious roots of mountain ginseng. A severe inhibition of NOX activity and decline in dry weight of SNP elicited adventitious roots in the presence of NOX inhibitor (diphenyl iodonium, DPI), which further supports involvement of NOX in root growth. Enhanced activities of antioxidant enzymes by SNP appear to be responsible for low H2O2, less lipid peroxidation, and modulation of ascorbate and non-protein thiol statuses in the adventitious roots of mountain ginseng. Dry mass, saponin content and NOX activity was related with NO content present in adventitious roots of mountain ginseng.

Genetic Improvement in Short Season Soybeans: I. Dry Matter Accumulation, Partitioning, and Leaf Area Duration

Genetic improvement of short‐season soybean [Glycine max (L.) Merr.] cultivars has resulted in a 0.5% annual gain in yield. Although yield is the product of dry matter (DM) accumulation and partitioning, the relative contributions of these two components of yield to genetic improvement has not been documented. Furthermore, the mechanism by which higher DM accumulation or harvest index (HI) is accomplished in the newer cultivars is unclear. The objective of the current study was to characterize DM accumulation and partitioning in cultivars which differ in yield potential, and determine the role of these traits in yield improvement. Two older (low yield potential) and two newer (higher yield potential) soybean cultivars of similar maturity were grown in side‐by‐side trials in 1996 and 1997. Plant samples were taken during each growing season and separated into leaves, stems + petioles, roots, and seeds. Dry matter accumulation and leaf area indices were measured. Seed yield of the new cultivars was 30% greater than their older counterparts. Increased DM accumulation contributed 78% and increased HI contributed 22% towards the genetic gain in yield. Total plant dry weight increased to a maximum around R4/R5 and subsequently declined during the seed‐filling period (SFP) as pod development increased and leaf senescence began. This decline in dry weight during the SFP was greater for the old than for the new cultivars. The newer cultivars maintained leaf area further into the SFP than the old cultivars enabling continued dry matter accumulation. The results of this experiment indicate that genetic yield improvement in the short‐season soybean cultivars examined was mainly associated with longer leaf area duration and the subsequently greater DM accumulation.

The regression of unsuckled mammary glands during lactation in sows: the influence of lactation stage, dietary nutrients, and litter size.

During lactation in the sow, mammary glands that are not regularly suckled undergo regression. This study characterizes the regression of unsuckled mammary glands and how that regression is affected by dietary nutrients and litter size. Sixty-nine primiparous sows were fed one of four diets containing combinations of two protein levels (32 or 65 g lysine/d) and two energy levels (12 or 17.5 Mcal ME/d) during lactation. Litter size was adjusted to 10. Sows were killed on d 0, 5, 10, 14, 21, or 28 of lactation. In another experiment, twenty-eight primiparous sows were allotted to have different litter sizes and were killed on d 21 of lactation. The day before slaughter, teat order of each litter was observed. After death, mammary glands were removed and dissected. Skin and extraneous fat pads were removed from the mammary glands and individual glands were separated. Each gland was weighed, cut in half to measure cross-sectional area, and ground for chemical analysis. The amounts of dry tissue, protein, fat, ash, and DNA were measured. Only glands observed to be unsuckled were included in the results. Regression of unsuckled mammary glands occurred rapidly during the first 7 to 10 d of lactation, as indicated by a decline in wet weight, dry weight, protein, fat, DNA, and cross-sectional area. The rate of regression was slowed after the early lactation period. The rate of regression of unsuckled glands was affected by dietary nutrient levels. Dietary energy level affected (P < 0.05) the decline in wet and dry weights, protein, fat and DNA content, and cross-sectional area, whereas dietary protein level affected (P < 0.05) the decline in dry weight and fat content. At d 5 of lactation, the wet weight of unsuckled mammary glands in sows fed the high-energy high-protein diet was 91% greater (P < 0.05) than in sows fed the low-energy low-protein diet. Effects of litter size on size and composition of unsuckled glands were not significant by d 21 of lactation. Unsuckled mammary glands regress rapidly during early lactation, and the rate of regression is affected by dietary nutrient intake.

Gut evacuation and absorption efficiency of walleye larvae

Gut evacuation and absorption efficiency in zooplanktivorous walleye Stizostedion vitreum larvae (10–19 mm; 0.53–6.8 mg dry weight) were examined in the laboratory. The decline in dry weight of whole digestive tract contents was examined at 15, 20, and 25) C in discontinuous feeding larvae. The observed relationship between short‐term evacuation rate and gut fullness indicated that evacuation approximated most closely an exponential decline. When gut evacuation rate, R, was calculated as the slope of loge gut fullness v. time there were significant effects of temperature and walleye size on R. Gut evacuation rate was higher at 20° C than at 15 or 25° C and declined with increasing walleye dry weight. Absorption efficiency at 20° C was examined by qualitative analysis of food and faeces. Apparent digestibility, Da, of crustacean zooplankton increased with gut retention time and declined with walleye dry weight. Maximum Da was estimated to be 79% of organic matter from food retained in the gut for 6 h.

Salinity effects on growth analysis and nutrient composition in four grain legumes‐rhizobiumsymbiosis

Abstract The effect of salinity on growth response, nitrogen (N) fixation and tissue mineral content was investigated for four legumes: faba bean (Vicia faba L), pea (Pisum sativum L), soybean (Glycine max L), and common bean (Phaseolus vulgaris L). Plants were grown in a vermiculite culture system supplied with a N‐free nutrient solution with the addition of 0, 50, and 100 mM NaCl. Plants were harvested at the beginning of the flowering period and the dry weights of shoots and roots and acetylene reduction activity (ARA) were evaluated at the same time plant tissues were analysed for N, potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) contents. The depressive effect of saline stress on ARA of nodules was directely related to the salt induced decline in dry weight and N content in shoots. Growth inhibition by NaCl treatments was greater for the pea than for other legumes, whereas the soybean was the most salt‐tolerant Saline stress also affected the N content in shoots and roots. In general th...

Effects of salt stress on growth and nitrogen fixation by pea, faba-bean, common bean and soybean plants

The effects of salinity on growth, nodulation, acetylene reduction activity (ARA), nodule leghemoglobin (Lb) content and respiratory capacity of bacteroids from pea ( Pisum sativwn cv. Lincoln), faba-bean ( Vicia faba L. var. minor cv. Alborea), bean ( Phaseolus vulgaris cv. Contender) and soybean ( Glycine max L. var. Williams) were determined. The depressive effect of saline stress (50 and 100 mM NaCl) on dry weight and ARA of nodules was directly related to the salt-induced decline in dry weight and N content in shoots. The results indicate that P. savitum was the legume most severely affected by salinity, whereas G. max was the most salt-tolerant species. Saline stress was also responsible for a decrease in cytosolic protein of nodules, specifically Lb; this effect was more pronounced in pea and bean nodules than in soybean and faba-bean nodules. Bacteroids isolated from soybean and bean nodules exhibited higher respiratory activity in the absence of energy-yielding substrates than those isolated from pea and faba-bean plants. Salt added directly to the incubation mixture of bacteroids inhibited O 2 uptake of bacteroids isolated from nodules of each legume. However, salt treatment of plants decreased respiratory capacity only in pea and faba-bean bacteroids. Inhibition of ARA under moderate saline stress may be related to the drop in bacteroid respiration. Under severe stress both the reduction in Lb content and inhibition of bacteroid respiration may be involved in salt-induced inhibition of nitrogen fixation.

Effect of root‐zone salinity on growth and chemical composition of Acacia ampliceps B. R. Maslin, A. auriculiformis A. Cunn. ex Benth. and A. mangium Willd at two nitrogen levels

summary Acacia ampliceps B. R. Maslin, A. auriculiformis A. Cunn. ex Benth. and A. mangium Willd. differ in their salt tolerance. Four‐month‐old seedlings were treated with 100 (S1), 200 (S2) and 400 (S3) mol m−3 NaCl in sand culture. Two months prior to NaCl application the seedlings had been pretreated with either 1 mol m−3 N (low N: LN) or 5 mol m−3 N (high N:HN) as ammonium nitrate. LN seedlings were inoculated with a suspension of Rhizobium.HN plants were considerably larger than inoculated plants at each NaCl concentration. Survival, damage symptoms and relative growth reduction under NaCl were generally similar for both N treatments. There was also no effect of N level on shoot water relations and stomatal conductance of youngest expanded phyllodes. However, at S1 and S2, HN plants had significantly lower concentrations of shoot Na+ and Cl− concentrations than LN plants.There were differences in nodule number and weight per plant between species receiving the LN treatment. Nodule dry weight and nitrogenase (acetylene reduction) activity was more sensitive than plant dry weight to NaCl imposition.Ranking of species for salt tolerance, based on relative decline in dry weight of shoot, whole plant and nodules under NaCl addition, was in the order A. ampliceps &gt; A. aurtculiformsis &gt; A. mangium. The greater salt tolerance of A. ampliceps was associated with relatively low shoot Na+ and Cl− concentrations (dry weight basis) and high phyllode succulence.

Effect of heterozygosity on metabolism during starvation in the American oysterCrassostrea virginica

Crassostrea virginica were collected in winter from the Nissequogue estuary, Long Island, New York, USA and starved for 42 d at 20°C in 28‰ salinity. Oxygen consumption (VO2) and ammonia excretion (VNH4), measured at about 20-d intervals, and changes in dry weight and carbohydrate content were tested for relationship with heterozygosity at six enzyme loci. Rate of decline in tissue dry weight during starvation was size-dependent, small oysters losing weight faster than large individuals. There was a significant effect of heterozygosity, the rate of weight loss decreasing with increasing heterozygosity. No significant correlation was found between heterozygosity and carbohydrate depletion rate, VO2 or VNH4. Carbohydrate content was positively correlated with size before and after starvation. Carbohydrate depletion contributed less to weight loss in small than in large oysters. This suggests that more lipid and protein was catabolised in small oysters. VO2 and VNH4 declined during the course of the experiment. There was good agreement between energy loss estimated from decline in dry weight and energy loss estimated from physiological measurements. We conclude that heterozygotes conserve weight more efficiently under temperature and nutritive stress and that this may be expected to enhance viability and growth.

Effects of temperature and salinity on oxygen consumption and nitrogen excretion in Thais (Nucella) lapillus (L.)

The 2-wk TLm of stepwise-acclimated Thais lapillus (L.) (>20 mm long) was 14.2–16.2%. salinity ( S) at 5, 10, 15, and 20°C. The same TLm occurred at 10 °C after direct transfer of snails to the final salinity but stepwise-acclimated small snails (<20 mm) tolerated a significantly lower salinity (12.7%. S). Oxygen consumption rates ( V ̇ O 2 ) fit the allometric equation V ̇ O 2 = a· W 0.60 ± 0.07 . Salinity and temperature had a significant effect on V ̇ O 2 , which was highest at 30%. S and depressed at 17.5%. S and at 5°C. Ammonia excretion rates fit the allometric equation V ̇ NH 4 + = a · W 0.61 ± 0.05 . Both salinity and temperature affected V ̇ NH 4 + . Ammonia excretion was significantly lower at 17.5 %. S than at higher salinities at 10, 15, and 20°C, but did not vary as a function of salinity at 5°C. Primary amines were lost from snails under all conditions without any obvious relationship with temperature or salinity. Primary-amine loss, expressed as a percentage of V ̇ NH 4 + , was significantly higher at 17.5 %. S than at higher salinities. Oxygen : nitrogen ratios ranged from 4.2–15.6, indicating protein was the primary metabolic substrate, and were highest at 15 °C and lowest at 5 °C. Snails withstood 89 days starvation without mortality at 10°C. Oxygen consumption of snails declined by 28% during starvation due to a 37% decline in dry weight; consequently, weight-specific respiration rate increased by 17%. The intercept ( a) for the V ̇ O 2 allometric equations did not change during starvation. Ammonia excretion increased during starvation, and primary-amine loss increased until Day 21, then declined. Oxygen: nitrogen ratios declined from 14 to 8, indicating an increased catabolism of protein during starvation.

Protein synthesis during the differentiation of sporangia in the water mold Achlya.

During the synchronous differentiation of sporangia in the absence of added nutrients, the water mold Achlya bisexualis (Coker and Couch) actively synthesized protein. Inhibition of protein synthesis at any time during the sporulation process completely inhibited further differentiation. Large changes in the rate of radioactive amino acid uptake resulted in changes in the specific activity of the cellular amino acid pool. The rate of protein synthesis was calculated from the amino acid pool specific activity and the incorporation of isotope into protein. During the 1st h after induction of the sporulation process, the rate of protein synthesis increased to two times the initial value. The amino acid precursors for this synthesis were supplied by the degradation of preexisting protein. Proteolytic enzyme activity assayed in vitro increased in proportion to the in vivo rates of protein synthesis and degradation. Differentiation was accompanied by a slight decline in dry weight of the mycelium as well as by a decrease in the protein content, whereas the relative size of the amino acid pools remained constant.