Changes In Dry Weight Research Articles

Assessment of dry weight by monitoring changes in blood volume during hemodialysis using Crit-Line

Routine assessment of dry weight in chronic hemodialysis patients relies primarily on clinical evaluation of patient fluid status. We evaluated whether measurement of postdialytic vascular refill could assist in the assessment of dry weight. Twenty-eight chronic, stable hemodialysis patients were studied during routine treatment sessions using constant dialysate temperature and dialysate sodium concentration, and relative changes in blood volume were monitored using Crit-Line III monitors throughout this study. The study was divided into three phases. Phase 1 studies evaluated the time-dependence of vascular compartment refill after completion of hemodialysis. Phase 2 studies evaluated the relationships in patient subgroups between intradialytic changes in blood volume and the presence of postdialytic vascular compartment refill during that last 10 minutes of hemodialysis after stopping ultrafiltration. Phase 3 studies evaluated the extent of dry weight changes following the application of a protocol for blood volume reduction, postdialytic vascular compartment refill, and correlation with clinical evidence of intradialytic hypovolemia and/or postdialytic fatigue. Phase 3 included anywhere from three to five treatments. Phase 1 studies demonstrated that despite interpatient variability in the magnitude of postdialytic vascular compartment refill, when significant refill was evident, it always continued for at least 30 minutes. However, the majority of refill took place within 10 minutes postdialysis. Phase 2 studies identified 3 groups of patients: those who exhibited intradialytic reductions in blood volume but not postdialytic vascular compartment refill (group 1), those who exhibited intradialytic reductions in blood volume and postdialytic vascular compartment refill (group 2), and those whose blood volume did not change substantially during hemodialysis treatment (group 3). In phase 3 studies, use of an ultrafiltration protocol for blood volume reduction and monitoring of postdialytic vascular compartment refill combined with clinical assessment of hypovolemia and postdialytic fatigue demonstrated that patients often had a clinical dry weight assessment which was too low or too high. In all 28 patients studied, dry weight was either increased or decreased following use of this protocol. Determination of the extent of both intradialytic decreases in blood volume and postdialytic vascular compartment refill, combined with clinical assessment of intradialytic hypovolemia and postdialytic fatigue, can help assess patient dry weight and optimize volume status while reducing dialysis associated morbidity. The number of hospital admissions due to fluid overload may be reduced.

Responses of jojoba explants to different salinity levels during the proliferation stage in vitro

Jojoba ( Simmondsia chinensis Link Schneider) explants were cultured under four levels of sodium chloride salinity (0, 56.4, 112.8 and 169.2 mM) during the proliferation stage. The fresh and dry weight of explants, as well as their mean shoot length increased up to the medium salt concentration, while the mean shoot number decreased. Salinity enhanced the length and thickness of leaves as well as the thickness of shoots. Sodium and chloride ions accumulated significantly under saline conditions while the opposite stood for nitrate ions as well as for potassium, which concentration decreased significantly in the high salt treatment. Ethylene evolution was highest under the high salt concentration and low at the low and medium salt treatment, even lower than that of the control and therefore it exhibited a significant strong negative relationship with the changes of both fresh and dry weight during the third month under saline conditions. Explants were transferred separately from each salt treatment to the rooting stage at the end of the third month. There were not any significant differences among explants deriving from different salt treatments in the rooting percentage, the root number and length, 6 weeks after the incubation of explants into the rooting medium.

Seasonal dynamics of resource translocation between the aboveground organs and age-specific rhizome segments of Phragmites australis

This study aims to test the hypothesis that resource translocation patterns between rhizomes and the aboveground organs depend not only on the season but also on rhizome age. Changes in rhizome biomass and storage reserves of Phragmites australis were therefore investigated to explore the age specificity of rhizomes in resource translocation patterns. Above and belowground biomass were harvested six times between April and December from an undisturbed monospecific stand, and analyzed to give rhizome age-specific dry mass and total non-structural carbohydrate (TNC) contents. Seven rhizome age-classes were recognized, from <1 to 6-year-old. Changes in dry weight and in TNC per unit area of each rhizome age-class were used to describe seasonal patterns in growth and mortality, translocation and movement of assimilates on an areal basis. TNC budgets were prepared based on these data and estimates of losses due to tissue mortality and respiration for each age-class. The seven age-classes had similar growth patterns but differed when translocation occurred, with older rhizomes translocating a substantial amount in spring to the aboveground organs to establish new shoots. Before summer, the photosynthates were evenly allocated to each age-class, while the recovery of TNC in segments was earlier with younger ones. The allocation in autumn was mainly to young rhizome segments. Older segments became severely depleted during winter, with high mortality; however, the youngest rhizome segments survived, which can be interpreted as an internal re-distribution of resources. This study clearly showed that there is a clear variation between rhizome age-classes in belowground resource translocation patterns depending on the season.

Changes of Micronutrients, Dry Weight, and Chlorophyll Contents in Strawberry Plants Under Salt Stress Conditions*

Various concentrations of NaCl (0, 500, 1000, and 2000 mg/L) were applied to plants of the “Camarosa” and “Tioga” strawberry varieties for 10 weeks. At the end of the experiment, it was determined that the leaf dry weight increased especially at 500 and 1000 mg/L NaCl treatments when compared to control treatment. However, salt applications did not change total chlorophyll content. With the salt applications, iron (Fe) and manganese (Mn) content increased, while copper (Cu) content did not change in the aerial part of plants in both varieties. On the other hand, zinc (Zn) content increased in the “Tioga” strawberry variety. In the root part of plants, Fe, Zn, Mn and contents did not change according to salt applications in both strawberry varieties. However, 2000 mg/L NaCl of salt applications increased Cu content in the “Camarosa” strawberry variety significantly. *This study is part of the Ph.D. thesis project supported by Uludag University Research Foundation as project no. 2000/24.

Predicting maize kernel sink capacity early in development

Development of maize ( Zea mays L.) kernels follows a predictable pattern involving rapid increase in dry weight and large changes in water content (WC). We showed previously that final kernel weight (KW) was closely correlated with maximum WC achieved during rapid grain filling. The objectives of the current work were (i) to test if percent moisture content (MC, measured on a fresh weight basis) could be used to normalize genetic and environmental variations in kernel development shown to affect final KW and (ii) to determine whether final KW could be predicted from kernel WC prior to rapid grain filling. The data examined included results from five hybrids varying more than 2-fold in final KW grown in the field, and from previously published results. When KW and WC were expressed relative to their maximum values obtained during kernel development, a single model described the relationship between dry weight accumulation and MC for the larger seeded hybrids (199–352 mg kernel −1) and published results (222–359 mg kernel −1). Two smaller seeded yellow-flint popcorn hybrids, however, accumulated less dry matter per unit moisture than expected. Nonetheless, all genotypes exhibited a common developmental relationship between kernel WC (expressed as a percent of the maximum value) and MC under well-watered conditions. A new model was developed to couple this developmental relationship to final KW. This model accurately predicted final KW from kernel WC values measured prior to rapid grain filling (∼80% MC; root mean square error, RMSE, of 28.9 mg kernel −1) for all hybrids examined and all published results for which KW and kernel WC data were available. The model also provided a simple means to determine whether final KW was limited by photosynthate supply during kernel development.

Cowpea reactions to Striga gesnerioides I. effect on growth

Field trials were conducted in 1993, 1994 and 1995 wet seasons to determine the effect of Striga gesnerioides on the vegetative growth of 16 cowpea varieties. These included 11 resistant varieties, 2 tolerant varieties and 3 susceptible varieties. The growth of S. gesnerioides on each of the cowpea varieties was also evaluated. The highest Striga infestation was observed on several cowpea varieties notably all the susceptible and several tolerant varieties. Cowpea varieties generally had root and shoot growth stimulation at 5 and 7 WAP under low Striga infestation in the late planted trial (LPT) in 1993 and the early planted trial (EPT) in 1994. There was no clear-cut difference in the change in the root dry weight of the resistant and susceptible varieties due to Striga infestation. However, heavy Striga infestation greatly reduced the root and shoot dry weight of most varieties, between 1994 and 1995 irrespective of sowing dates. Greater reduction was observed in the leaf area and root nodules of the susceptible than resistant cowpea varieties. The susceptible varieties had conspicuous reduction in shoot dry weight at 9 WAP in each trial. The reduction in cowpea shoot dry weight due to Striga infestation was slightly greater in the LPT than EPT, and there was an increasing tendency towards greater reduction of the shoot dry weight from the trial in 1993–1995, due to increasing level of infestation. The losses usually observed in the cowpea host productivity could be due to the reduction in the root nodulation, leaf area, root and shoot growth under Striga infestation.

Appearance and development of tillers in herbage grass species 2. Timothy (Phleum pratense L.)

AbstractThe persistence of timothy in grasslands was investigated in the present study. Seeds were sown in August and October 1999 and March 2000. Following transplantation in September and November 1999 and April 2000, plant length and dry matter weight of each organ were measured in every tiller every three months.The results were obtained under the limited conditions of uninterrupted growth of timothy plants in the sward. The seasonal changes in plant lengths of the first year of establishment differed with the sowing times. In the second year, the tillers were divided into two by means of seasonal changes in plant length: some tillers increasing rapidly during the growing season from spring to late spring and the others gradually from autumn to winter. In the second year, the seasonal changes in the total tiller numbers of differing sowing times showed almost the same pattern, and secondary and tertiary tillers alternating with the main culm and primary tiller predominated. The changes in dry matter weight of each organ, especially the changes of the haplocorms, corresponded with the alternations of generations of tillers. That is, the parental tillers provided nutrients to haplocorms until the main tillers bore ears and developed. The parental tillers suppressed the appearance of tillers of the next generation to avoid competition. The tillers of the next generation began to emerge after the parental tillers died. The mechanism of the harmonious alternation of tiller generations composed of several tiller order groups was inferred to be one of the factors allowing the persistence of the timothy sward.

Application of an Automatic Control System of Photosynthetic Photon Flux Density for LED-Low Light Irradiation Storage of Green Plants

A light-emitting diode (LED)-low light irradiation (LLI) storage system was developed for suppressing the change in dry weight and maintaining the quality of green plants during long-term storage. In this system, the carbon dioxide (CO2) exchange rate was maintained at zero by automatically adjusting the photosynthetic photon flux density (PPFD) with a proportional-integralderivative (PID) controller. The voltage supplied to the LEDs was controlled by the difference between the inflow (400 μmol·mol-1) and outflow CO2 concentrations in the storage case. Grafted tomato (Lycopersicon esculentum; scion = `House Momotaro'; rootstock = `Anchor T') plug seedlings were stored at 10 °C for 35 days under four different LLI conditions as a system operating test: fixed red light irradiation at 2 μmol·m-2·s-1, PID-controlled red light irradiation with no blue light, and PID-controlled red light irradiation with blue light at 0.2 or 1.0 μmol·m-2·s-1. The results showed that the automatic PPFD control during LED-LLI helped suppress changes in dry weight during storage as expected. Furthermore, it was found that addition of a low percentage of blue light improved the morphological appearance of the seedlings and reduced the PPFD required to suppress the change in dry weight.

Cell wall immobilisation and antioxidant status of Xanthoria parietina thalli exposed to cadmium.

Total and cell wall-bound cadmium and the major antioxidants were measured in thalli of the lichen Xanthoria parietina (L.) Th. Fr. exposed to two Cd concentrations, namely 4.5 or 9.0 μm, in liquid medium during exposure periods of either 24 or 48 h. Total Cd in the thalli was within the range of previous field measurements and was proportional to the exposure concentration, but less than proportional with respect to exposure duration. More than half of the total Cd was immobilised by the cell wall. The adopted conditions of Cd stress caused: (i) no changes in dry weight and protein concentration; (ii) an increase in the level of ascorbic acid and a decrease in that of reduced glutathione, as well as an increase in guaiacol peroxidase activity; (iii) no changes or moderate decreases in the activities of superoxide dismutase, catalase, dehydroascorbate-, NADPH-dependent glutathione disulfide-, and monodehydroascorbate reductases and of ascorbate peroxidase; (iv) an increase of the level of thiobarbituric acid-reactive substances, assumed to reflect malondialdehyde formation arising from membrane lipid peroxidation. Thus, X. parietina might withstand realistic levels of Cd stress by: (1) intercepting the heavy metal at cell wall level, (2) the intervention of antioxidant metabolites, and (3) a moderate increase in guaiacol peroxidase activity.

Plant carbohydrate partitioning of Lachenalia cv. Ronina during bulb production

Carbohydrate partitioning was investigated in different plant organs of Lachenalia cv. Ronina during bulb production under a low temperature regime. At 4-week intervals, data were collected on bulb, roots, leaves, inflorescence and carbohydrate composition. The roots and especially the bulb were found to be the main starch sinks of the plant, whilst the leaves and the inflorescence were the main source for soluble sugars. Changes in the starch concentration closely followed dry weight changes in the bulb during the growing season. When bulbs were initially exposed to a low temperature, starch was converted to soluble sugars, but thereafter sugars were low, indicating continued export and conversion to starch. Low sugar levels in the leaves and high levels in the inflorescence, with continuous starch increase in the bulb and roots, probably indicate that the inflorescence, but especially the leaves, produced ample photosynthates during the growing season.

English

Phosphatases are widely found in plants having intracellular and extracellular activities. Phosphatases are believed to be important for phosphorous scavenging and remobilization in plants, but its role in adaptation to abiotic stresses and growth hormones at germination level has not been critically evaluated. To address this issue, the effect of ABA, GA3, NaCl and drought on germination, growth, acid and alkaline phosphatases in sorghum embryos and endosperm was investigated. Germination decreased markedly under ABA, NaCl and drought treatments. Subsequently, a remarkable decrease in fresh weight and dry weight was observed in embryos under ABA and NaCl treatments, whereas a significant decrease in endosperm fresh weight was observed only under drought stress. However, no significant change in endosperm dry weight was observed under other any treatment. Furthermore, a considerable increase in acid phosphatse activity was observed in embryos under GA3&nbsp;and NaCl treatments, however, alkaline phosphatase activity was substantially higher under all treatments. In endosperm, a significant increase in acid phosphatase activity was observed under ABA and NaCl treatments. Alkaline phosphatse activity was apparently higher under GA3. However, no substantial changes in acid or alkaline phosphatase activities were observed after drought treatments. These findings suggest that changes in the phosphatase enzymes might play important roles in adaptation of germinating seeds, to changing environmental conditions.&nbsp; Based upon these results, a possible physiological role of phosphatases in germinating sorghum seeds is discussed. &nbsp; Keywords: Growth, sorghum, acid phosphatase, alkaline phosphatase.

Thermoregulation and water balance as affected by water and food restrictions in Sudanese desert goats fed good-quality and poor-quality diets.

Nine desert goats were used in a 3 x 3 Latin square design in which they were subjected to (a) ad libitum water and food (control), (b) ad libitum food and water restricted to about 40% of the control, and (c) ad libitum water and restricted food (same amount as given to group b). Parameters measured were dry matter intake (DMI), water intake, rectal temperature (Tr), respiration rate (RR), water balance and body weight (BW) changes. The acute effects of the above treatments on these parameters were monitored during the dry summer using two types of feed. The ratio of DMI to water intake decreased (p < 0.01) due to water restriction but increased (p < 0.01) with Lucerne hay compared to grass hay. With both feeds, BW decreased (p < 0.01) with water restriction, with a further decrease (p < 0.01) observed with food restriction. The control group showed a higher (p < 0.01) gain with Lucerne hay than grass hay. Tr and RR increased (p < 0.01) from morning to afternoon; Tr decreased due to food restriction during both morning and afternoon with Lucerne hay (p < 0.05) and grass hay (p < 0.05), whereas RR decreased (p < 0.01) with both types of feeds. For all groups of animals, Tr was higher (p < 0.05) with Lucerne hay than with grass hay, this effect being more pronounced (p < 0.01) with the control group. With both feeds, water restriction decreased (p < 0.01) water turnover rate and evaporative losses, with decreased (p < 0.05) faecal losses observed in the water-restricted groups on Lucerne hay but higher (p < 0.05) losses of urine. The tolerance of desert goats to thermal stress and their coping with shortage of water and food depended on their capacity to lose heat through panting and cutenaous evaporation as well as their ability to concentrate urine.

Seed dry weight response to source–sink manipulations in wheat, maize and soybean: a quantitative reappraisal

Determining to what degree seed weight differences are due to competition among seeds for insufficient source is critical for the rational design of breeding and management strategies aimed at maximizing crop yields. While the crop physiology literature cites many examples of source and/or sink yield limitations during seed filling, interpretation of these data has usually been qualitative in nature, biasing our view of the source–sink yield limitations during this period. In the present review, we applied a quantitative approach for determining the magnitude of seed dry weight changes in response to manipulations in assimilate availability during seed filling for previously published articles in wheat ( Triticum aestivum), maize ( Zea mays L.) and soybean ( Glycine max L.). This quantitative approach demonstrates that yield is usually more sink than source limited during seed filling in the three crops, though: (i) interspecific variation exists in the magnitude of limitation, and (ii) intraspecific variability is larger in soybean than in cereals. Seeds of wheat appeared to grow mostly at saturated assimilate availability, so yield is mainly sink limited in all growing conditions×cultivar combinations explored in the analysis. Soybeans seem to experience a large degree of co-limitation by the source and the sink, as seeds greatly respond to source–sink modifications. Maize displayed a consistent trend to dramatic reductions in seed dry weight when assimilates produced during seed filling are reduced, but a virtual lack of responsiveness to improvements in potential availability of assimilates per growing seed. This results in a sink-limited crop in most growing conditions, but a source-limited crop if resource availability is strongly reduced during seed filling.

The nutritional value of Zizyphus spina-christi for goat production among the pastoralists of Kalu district, South Wello, Ethiopia

Fifteen yearling goats of similar weight were used to evaluate the potential of Zizyphus spina-christi leaves as a supplement to goats fed on Cynodon dactylon grass. Animals were randomly assigned to five feeding regimes and individually stall-fed for a preliminary period of 14 days, followed by 14 days of feeding to determine dry matter intake and digestibility and a 3-month feeding period to determine body weight changes. The treatments were formulated based on leaf:grass ratios of 0%, 25%, 50%, 75% and 100%. Z. spina-christi leaves had higher crude protein and lower fibre content than C. dactylon grass (P < 0.05). Dry matter intake, digestibility and body weight changes increased significantly (P < 0.05) as the level of supplementation increased. Thus, Z. spina-christi foliage is a potential feed supplement in the dry season, as the dry season grasses are deficient in the required nutrients and cannot meet goat requirements.

Late‐season temperature effects on the carbon economy and tree performance of ‘Royal Gala’ apple (Malusdomestica) trees

Potted ‘Royal Gala’ apple on M.9 rootstock (Malus domestica) trees were grown after fruit harvest at constant temperature conditions (18/ 8°C day/night) for 3, 6, and 9 weeks to manipulate their carbohydrate reserves. On several occasions, leaf gas exchange was measured and selected trees were destructively harvested before and after each treatment to measure the dry weight of the component parts. Samples were also taken for carbohydrate analysis. After treatment, the remaining trees were returned outdoors and, in spring, selected trees from each treatment were destructively harvested for dry weight and carbohydrate analysis. Budbreak was then measured and fruit weight and crop load determined next autumn and the trees destructively harvested for dry weight and carbohydrate analysis. There was no change in tree dry weight after each late‐season temperature treatment. Carbohydrate concentrations, averaged over the whole tree, increased by 10–15% compared to the pre‐treatment trees, consistent with a net increase in carbon acquisition. Over winter, the total carbohydrate concentration had declined by 25–40%. In spring, time of budbreak differed significantly; trees exposed for 3 weeks to 18/8°C in late‐season broke buds 9–19 days earlier than the other treatments in the following spring. The early budbreak was associated with not only the largest increase in carbohydrate concentration during treatment but also the greatest decrease thereafter. Although there is some support for the conclusion that high carbohydrate reserves confer a direct benefit on the budbreak process, it remains an open question if it was the increase in reserves, or their subsequent consumption that advanced budbreak.

Effects of Different Transition Diets on Dry Matter Intake, Milk Production, and Milk Composition in Dairy Cows

The primary objective of this study was to evaluate the effect on dry matter intake (DMI), milk yield, milk composition, body weight (BW), and body condition score (BCS) change of cows offered diets differing in energy density in the last 4 wk of gestation and in the first 8 wk of lactation. Three diets (grass silage:straw, 75:25 on a dry matter basis (SS), grass silage (S), and grass silage + 3kg concentrate daily (C)) precalving, and two diets (4kg [LC] or 8kg [HC] concentrate daily + grass silage ad libitum) postcalving were combined in a 3×2 factorial design. Sixty Holstein-Friesian cows entering their second lactation were blocked according to expected calving date and BCS into groups of six and were then allocated at random to the treatments. Individual feeding started 4 wk prior to the expected calving date and measurements were made until the end of the 8th wk of lactation. Mean DMI differed between each of the precalving treatments (7.4, 8.1, and 9.9kg/d for SS, S, and C, respectively) in the precalving period. The DMI also differed between SS and C for wk 1 to 8 (13.5 and 14.2kg/d) postcalving. Postcalving, milk (24.2, 26.2, and 28.2kg/d), fat (933, 1063, and 1171g/d), and protein (736, 797, and 874g/d) yields differed between SS, S, and C, respectively. The BCS changes differed between SS and C (−0.09 and 0.12 of a BCS) in the precalving period and between SS and S compared with C (0.02, 0.06, and −0.26 of a BCS) for wk 1 to 8 postcalving. The BW change differed between SS and S compared with C in both wk 1 to 4 (−0.23, −0.37, and −1.25kg/d) and wk 1 to 8 (0.18, 0.10, and −0.58kg/d) postcalving. The BW and BCS were lower at calving for cows on SS compared with C. The greater amount of concentrate supplement postcalving increased DMI, yields of milk, fat, and protein and decreased BW loss in the first 8 wk of lactation. In conclusion, these results indicate that a greater energy density diet in the final 4 wk of the dry period improves cow production in early lactation.

Volatile communication between barley plants affects biomass allocation.

Patterns of biomass allocation between different plant organs have often been used to explain the response of plants to variations in resource availability. This paper reports how aerial allelopathy (plant-plant communication) affects biomass allocation, that is the trade-off between root, stem and leaves, and also relative growth rate (RGR, increase in biomass per unit biomass per unit of time, mg g-1 d-1) and its components. Based on previous experiments, communication between two barley (Hordeum vulgare L.) cultivars (Alva and Kara) was used for the present study. Kara exposed to volatiles from Alva allocated significantly more biomass to roots compared with Kara exposed to volatiles from Kara or to clean air. There was no significant difference between plants of Kara exposed to volatiles from Kara and those exposed to clean air. Changes in total dry weight (TDW), RGR and unit leaf rate (ULR, increase in biomass per unit time and leaf area, kg m-2 d-1) were not significantly affected by plant-plant communication. However, there was a significant increase in specific leaf area (SLA, leaf area per leaf dry weight, m2 kg-1) in Kara when exposed to volatiles from Alva. The results show that aerial plant-plant communication does not affect total biomass production but does significantly affect biomass allocation in individual plants. There may be differences in the volatile profiles of Kara and Alva that induce increased biomass allocation to roots in the Kara plants exposed to volatiles from Alva.

Reproduction of Venus verrucosa L., 1758 (Bivalvia: Veneridae) in the littoral of Málaga (southern Spain)

The reproductive cycle of Venus verrucosa Linnaeus, 1758 was studied using histology and changes in flesh dry weight, in the littoral of Málaga (southern Spain), from June 1999 to May 2000. Histological study of the gonads showed spawning throughout the year, with two peaks. The first lasts from March to April, and is accompanied by the highest decrease of weight; the second is from May to August with the highest percentage of population spawning. There is new activation of the gonads from postactive stages, without passing through a resting period (with a high percentage of the population in the cytolized stage). The absence of a resting period in the reproductive cycle could be explained by the mild seawater temperatures and high levels of chlorophyll a in the littoral of Málaga. In the light of these data, we propose a closed season from March to April, months during which there was the most intense release of gametes in the population.

Effect of Acacia tortilis pods on intake, digestibility and nutritive quality of goat diets in southwestern Eritrea

Fresh Acacia tortilis pods were mixed with low quality native grass hay to form the following five rations: 100% hay (T1), 25% pods and 75% hay (T2), 50% pods and 50% hay (T3), 75% pods and 25% hay (T4) and 100% pods (T5) on 'as fed' weight basis. Fifteen male Barka goats, approximately one year old and 10-15kg body weight, were randomly assigned to the five rations and fed in individual pens. Chemical composition, dry matter intake (DMI), in vitro dry and organic matter digestibility and body weight changes of the animals were evaluated. The average crude protein content of the pods was about 47% higher than the 7% minimum required for normal rumen function, while that of the hay was about 13% below. Percent ash, neutral detergent fibre (NDF), acid detergent fibre (ADF), hemi-cellulose (HC), cellulose (CL) and acid detergent lignin (ADL) contents were higher in the hay than in the pods. The pods were, however, generally higher in Ca, P, Mg and Na than the hay. Average DMI (g d-1 and g kg-1 LBW), percent in vitro dry and organic matter digestibility and body weight gains (total kg and gd-1) increased with an increase in A. tortilis pods, up to 75% level and then begun to decline. However, despite the decrease, T5 still had significantly (P < 0.05) higher feed digestibility and body weight gains than T2 and T3. Thus, supplementing low quality range herbage with Acacia pods can considerably improve the nutritive value of range livestock diets, particularly during the dry season when other types of fodder are of extremely low quality.

Tassel Morphology as an Indicator of Potential Pollen Production in Maize

Adequate pollen production is an essential prerequisite for achieving high yields in commercial corn (Zea mays L.) production and for insuring high levels of genetic purity in the production of hybrid seed. Documenting the timing and intensity of pollen shed are fundamental to these goals, but methods to describe patterns of pollen release from maize tassels are limited and laborious. Our objective was to explore characteristics of tassel morphology that could be used as simple and indirect measures of pollen production per plant under field conditions. The progress of tassel development was documented using a nine-stage scale based on easily-quantified morphological characteristics. Genetic variation among hybrids and inbreds as well as environmental variation across planting densities and years was correlated with levels of pollen production. This analysis revealed that a change in tassel dry weight during pollen shed was not an accurate measure of pollen production per tassel. Likewise, no single morphological characterization captured all the genetic and environmental variation in pollen production per tassel. But a combination of morphological traits incorporated into a Tassel Area Index (TAI) accounted for up to 89% of the variation in pollen production among hybrids in response to population density, and 64% of the variation in pollen production among inbred heterotic groups. Because data collection is simple, quick, and non-destructive, the Tassel Area Index approach is well-suited for distinguishing genetic variation in pollen production and relative responses to treatments under field conditions. The accuracy of the technique could be increased, if necessary, by incorporating additional information about flower density or pollen production per anther. But this would entail a much greater investment of time and resources.