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Final Harvest (final + harvest)
Selected AbstractsSeasonal changes in the effects of elevated CO2 on rice at three levels of nitrogen supply: a free air CO2 enrichment (FACE) experimentGLOBAL CHANGE BIOLOGY, Issue 6 2003HAN-YONG KIM Abstract Over time, the stimulative effect of elevated CO2 on the photosynthesis of rice crops is likely to be reduced with increasing duration of CO2 exposure, but the resultant effects on crop productivity remain unclear. To investigate seasonal changes in the effect of elevated CO2 on the growth of rice (Oryza sativa L.) crops, a free air CO2 enrichment (FACE) experiment was conducted at Shizukuishi, Iwate, Japan in 1998,2000. The target CO2 concentration of the FACE plots was 200 µmol mol,1 above that of ambient. Three levels of nitrogen (N) were supplied: low (LN, 4 g N m,2), medium [MN, 8 (1998) and 9 (1999, 2000) g N m,2] and high N (HN, 12 and 15 g N m,2). For MN and HN but not for LN, elevated CO2 increased tiller number at panicle initiation (PI) but this positive response decreased with crop development. As a result, the response of green leaf area index (GLAI) to elevated CO2 greatly varied with development, showing positive responses during vegetative stages and negative responses after PI. Elevated CO2 decreased leaf N concentration over the season, except during early stage of development. For MN crops, total biomass increased with elevated CO2, but the response declined linearly with development, with average increases of 32, 28, 21, 15 and 12% at tillering, PI, anthesis, mid-ripening and grain maturity, respectively. This decline is likely to be due to decreases in the positive effects of elevated CO2 on canopy photosynthesis because of reductions in both GLAI and leaf N. Up to PI, LN-crops tended to have a lower response to elevated CO2 than MN- and HN-crops, though by final harvest the total biomass response was similar for all N levels. For MN- and HN-crops, the positive response of grain yield (ca. 15%) to elevated CO2 was slightly greater than the response of final total biomass while for LN-crops it was less. We conclude that most of the seasonal changes in crop response to elevated CO2 are directly or indirectly associated with N uptake. [source] The number of CD34+ cells in peripheral blood as a predictor of the CD34+ yield in patients going to autologous stem cell transplantationJOURNAL OF CLINICAL APHERESIS, Issue 2 2006A.L. Basquiera Abstract The number of CD34+ cells in peripheral blood (PB) is a guide to the optimal timing to harvest peripheral blood progenitor cells (PBPC). The objective was to determine the number of CD34+ cells in PB that allows achieving a final apheresis product containing ,1.5 × 106 CD34+ cells/kg, performing up to three aphereses. Between March 1999 and August 2003, patients with hematological and solid malignancies who underwent leukapheresis for autologous bone marrow transplantation were prospectively evaluated. Seventy-two aphereses in 48 patients were performed (mean 1.45 per patient; range 1,3). PBPC were mobilized with cyclophosphamide plus recombinant human granulocyte-colony stimulating factor (G-CSF) (n = 40), other chemotherapy drugs plus G-CSF (n = 7), or G-CSF alone (n = 1). We found a strong correlation between the CD34+ cells count in peripheral blood and the CD34+ cells yielded (r = 0.903; P < 0.0001). Using receiver-operating characteristic (ROC) curves, the minimum number of CD34+ cells in PB to obtain ,1.5 × 106/kg in the first apheresis was 16.48 cells/,L (sensitivity 100%; specificity 95%). The best cut-off point necessary to obtain the same target in the final harvest was 15.48 cells/,L, performing up to three aphereses (sensitivity 89%; specificity 100%). In our experience, ,15 CD34+ cells/,L is the best predictor to begin the apheresis procedure. Based on this threshold level, it is possible to achieve at least 1.5 × 106/kg CD34+ cells in the graft with ,3 collections. J. Clin. Apheresis 2005. © 2005 Wiley-Liss, Inc. [source] Assessing the Suitability of Various Physiological Traits to Screen Wheat Genotypes for Salt ToleranceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2007Salah E. El-Hendawy Abstract Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels (control and 150 mmol/L NaCl) in a greenhouse. The physiological traits (ion contents in leaves and stems, i.e. Na+, Cl,, K+, Ca2+), the ratios of K+/Na+ and Ca+/Na+ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content (SPAD value), and leaf water relations, were measured at different growth stages. The physiological traits except for Na+ and Cl, in stems and the leaf transpiration rate at 150 mmol/L NaCl showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca2+ and Ca2+/Na+ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca2+ in plant tissues. [source] Impact of organic and inorganic fertilizers on yield, taste, and nutritional quality of tomatoesJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 4 2006Anuschka Heeb Abstract In a greenhouse experiment, tomato plants were grown in sand culture to test whether different fertilization regimes (mineral or organic fertilizers) at low (500 mg N plant,1 week,1) and high (750 mg N plant,1 week,1) nitrogen levels affected yield, nutritional quality, and taste of the fruits. In the mineral-fertilizer treatments, nitrate- or ammonium-dominated nutrient solutions were used. Organic fertilizer was supplied as fresh cut grass-clover mulch (a total of 2.4,kg and 3.6,kg were given per plant at low and high N level, respectively) without (orgN) and with additional sulfur fertilization (orgN+S). Yields of red tomatoes from the organically fertilized plants were significantly lower (1.3,1.8,kg plant,1) than yields from plants that received mineral fertilizer (2.2,2.8,kg plant,1). At the final harvest, yields of green tomatoes in the organic treatment with extra sulfur were similar (1.1,1.2,kg plant,1) to the NO -dominated treatments at both nutrient levels and the NH -dominated treatment at high nutrient level. Organic fertilizers released nutrients more slowly than mineral fertilizers, resulting in decreased S and P concentrations in the leaves, which limited growth and yield in the orgN treatments. Analysis of tomato fruits and plants as well as taste-test results gave no conclusive answer on the relationship between sugar or acid contents in the fruits, macronutrient content of plant leaves and fruits, and perceived taste. Sugar contents were higher in the fruits given mineral fertilizer, whereas acid contents were higher in the fruits given organic fertilizer. Preference in taste was given to the tomatoes from plants fertilized with the nitrate-dominated nutrient solution and to those given organic fertilizer with extra sulfur. Thus, a reduction in growth, which was expected to lead to a higher concentration of compounds like sugars and acids, did not result in better taste. Overall, it can be concluded that an appropriate nutrient supply is crucial to reach high yields and good taste. [source] Effects of elevated CO2, drought and temperature on the water relations and gas exchange of groundnut (Arachis hypogaea) stands grown in controlled environment glasshousesPHYSIOLOGIA PLANTARUM, Issue 1 2000Sean C. Clifford Stands of groundnut (Arachis hypogaea L. cv. Kadiri-3) were grown in controlled environment glasshouses at mean atmospheric CO2 concentrations of 375 or 700 ,mol mol,1 and daily mean air temperatures of 28 or 32°C on irrigated or drying soil profiles. Leaf water (,l) and solute potential (,s), relative water content (RWC), stomatal conductance (gl) and net photosynthesis (Pn) were measured at midday for the youngest mature leaf throughout the growing season. Elevated CO2 and temperature had no detectable effect on the water relations of irrigated plants, but higher values of RWC, ,l and ,s were maintained for longer under elevated CO2 during progressive drought. Turgor potential (,p) reached zero when ,l declined to ,1.6 to ,1.8 MPa in all treatments; turgor was lost sooner when droughted plants were grown under ambient CO2. A 4°C increase in mean air temperature had no effect on ,s in droughted plants, but elicited a small increase in ,l; midday gl values were lower under elevated than under ambient CO2, and ,l and gl declined below ,1.5 MPa and 0.25 cm s,1, respectively, as the soil dried. Despite the low gl values recorded for droughted plants late in the season, Pn was maintained under elevated CO2, but declined to zero 3 weeks before final harvest under ambient CO2. Concurrent reductions in gl and increases in water use efficiency under elevated CO2 prolonged photosynthetic activity during drought and increased pod yields relative to plants grown under ambient CO2. The implications of future increases in atmospheric CO2 for the productivity of indeterminate C3 crops grown in rainfed subsistence agricultural systems in the semi-arid tropics are discussed. [source] The influence of ultraviolet radiation on growth, photosynthesis and phenolic levels of green and red lettuce: potential for exploiting effects of ultraviolet radiation in a production systemANNALS OF APPLIED BIOLOGY, Issue 3 2010E. Tsormpatsidis Studies have shown that natural ultraviolet (UV) radiation increases secondary products such as phenolics but can significantly inhibit biomass accumulation in lettuce plants. In the work presented here, the effect of UV radiation on phenolic concentration and biomass accumulation was assessed in relation to photosynthetic performance in red and green lettuce types. Lettuce plants in polythene clad tunnels were exposed to either ambient (UV transparent film) or UV-free conditions (UV blocking film). The study tested whether growth reduction in lettuce plants exposed to natural UV radiation is because of inhibition of photosynthesis by direct damage to the photosynthetic apparatus or by internal shading by anthocyanins. Ambient levels of UV radiation did not limit the efficiency of photosynthesis suggesting that phenolic compounds may effectively protect the photosynthetic apparatus. Growth inhibition does, however, occur in red lettuce and could be explained by the high metabolic cost of phenolic compounds for UV protection. From a commercial perspective, UV transparent and UV blocking films offer opportunities because, in combination, they could increase plant quality as well as productivity. Growing plants continuously under a UV blocking film, and then 6 days before the final harvest transferring them to a UV transparent film, showed that high yields and high phytochemical content can be achieved complementarily. [source] Effects of selective harvesting and claw ablation of all-male freshwater prawn (Macrobrachium rosenbergii ) on water quality, production and economics in polyculture pondsAQUACULTURE RESEARCH, Issue 10 2010Sheikh Md. Abstract The effects of selective harvesting (SH) and claw ablation (CA) of blue-clawed (BC) prawns on an all-male freshwater prawn,finfish polyculture system were compared with control (Co) in quadruplicate. Ponds were stocked with all-male freshwater prawn Macrobrachium rosenbergii, silver carp Hypophthalmichthys molitrix, catla Catla catla and mola Amblypharyngodon mola at 12 000, 2000, 500 and 20 000 ha,1 respectively. Prawns were fed with pelleted feed. Ponds were fertilized regularly with urea, triple super phosphate and cow-dung. SH of BC prawns in treatment SH and CA in treatment CA started on the 60th day during a 137-day culture and continued at 15-day intervals until the final harvest. Water quality parameters and plankton abundance did not vary significantly (P>0.05) among the treatments. Treatment SH resulted in a higher (P<0.05) net production of freshwater prawn (437 kg ha,1), with better survival and mean weight, followed by CA (354 kg ha,1) and Co (322 kg ha,1). The combined net production of prawn plus finfish was also higher in SH (1244 kg ha,1) as compared with CA (1161 kg ha,1) and Co (1137 kg ha,1), although the finfish production did not differ significantly. The periodic SH of BC prawns showed a better economic return with a BCR of 1.71. [source] Density effects of silver carp Hypophthalmichthys molitrix and catla Catla catla on the production system in all-male freshwater prawn,finfish polyculture pondsAQUACULTURE RESEARCH, Issue 10 2010Sheikh Md. Abstract The effects of three different combinations of silver carp Hypophthalmichthys molitrix and catla Catla catla density on the production system in all-male freshwater prawn,finfish polyculture ponds were evaluated in triplicate. The stocking density of silver carp and catla, respectively, were maintained at 2000 and 500 ha,1 in treatment SC2000C500, 1500 and 1000 ha,1 in treatment SC1500C1000 and 1000 and 1500 ha,1 in treatment SC1000C1500. Male freshwater prawn Macrobrachium rosenbergii and small fish mola Amblypharyngodon mola densities were fixed in all treatments at 12 000 and 20 000 ha,1 respectively. Management practices were same for all treatments. Blue-clawed male prawns were harvested twice during the 122-day culture at 15-day intervals before the final harvest. Plankton and macro-benthos abundance and water quality parameters (except transparency and chlorophyll a) did not vary significantly (P>0.05) among treatments. Mean final weights of both silver carp and catla were decreased with the increasing of their own stocking density. The treatment SC1500C1000 resulted in 25,32% increased net production of silver carp plus catla (461 kg ha,1) and 20,21% increased net production of all species combined (874 kg ha,1) as compared with the other treatments, although the differences in production of prawn and mola among treatments were not significant. [source] Growth performance of mixed sex, hormonally sex reversed and progeny of YY male tilapia of the GIFT strain, Oreochromis niloticusAQUACULTURE RESEARCH, Issue 6 2009Norhidayat Kamaruzzaman Abstract The growth performance of three experimental groups consisting of mixed sex fish (control), hormone-treated fish and progeny of YY male tilapia, all originated from the genetically improved farmed tilapia (GIFT) strain was evaluated. Masculinization of sexually undifferentiated fry was achieved by providing a supplement of 5 mg of 17-,-methyltestosterone per kg of feed over a period of 21 days (after sac absorption). Both mixed sex and progeny of YY male groups were fed a standard commercial ration. Mixed sex fish did not deviate significantly (P>0.05) from the 1:1 male to female ratio. Percentages of male averaged 75% in hormone-treated fish and 95% in YY male group over the sampling periods and at final harvest. The effect of sex on weight and length was statistically significant (P<0.001). The model used to analyse weight and length included experimental group and sex in each culture period as the fixed effects, and replicate cages as the random effect. Over the culture period of 141 days, there were no statistical differences (P>0.05) in body weight and length between mixed sex, hormonally treated and progeny of YY males. There were also no significant differences in level of variability in harvest weight between three groups of fish when the data were classified into five categories (=<100, 100 to <150, 150 to <200, 200 to <250 and ,250 g). It is concluded that monosex culture of all male tilapia would be of no advantage over mixed sex culture for the GIFT strain under conditions of cages suspended in earthen ponds. [source] | |||||||||||||