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991.
992.
Elevated atmospheric CO2 improved Sorghum plant water status by ameliorating the adverse effects of drought 总被引:2,自引:0,他引:2
993.
Thi Nguyen Quynh Kozai Toyoki Heo Jeongwook Xuan Thai Du 《Plant Cell, Tissue and Organ Culture》2001,66(3):217-225
Effects of two ventilation methods (forced and natural) and two photosynthetic photon fluxes (PPF, 150 and 250 μmol m−2 s−1) on the photoautotrophic growth of in vitro cultured coffee (Coffea arabusta) plantlets were investigated. Number of air exchanges was 2.7, 5.9 and 3.9 h−1 for forced low rate, forced high rate and natural ventilation, respectively. Single node cuttings of in vitro cultured coffee plantlets were cultured on Florialite, a mixture of vermiculite and cellulose fibers with high air porosity,
emerged in liquid half strength basal MS medium, without sucrose, vitamins and plant growth regulators. The study included
40 days in the in vitro stage and 10 days in the ex vitro stage. Mean fresh and dry weights, leaf area, shoot and root lengths and net photosynthetic rate per plantlet were significantly
greater in forced high rate treatments compared with those in natural and forced low rate treatments. PPF had a distinct effect
on shoot length suppression and root elongation of coffee plantlets in forced high rate treatments. The control of carbon
dioxide concentration inside the culture box according to the plant demand when growing was easy with the forced ventilation
method in photoautotrophic micropropagation.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
994.
The modified sulfite oxidation method was adapted for estimation of the overall oxygen transfer rate in a pressure oscillating, solid-state fermenter. At 4.5 atm and 30 °C, the oxygen transfer rate reached 717 mmol kg–1 initial dry matter h–1 in this system against 37 mmol kg–1 initial dry matter h–1 in a static tray fermenter. At 30 °C and 3 atm, Azotobacter vinelandii grew on wheat straw and reached 4.7×1010 c.f.u. g–1 substrate dry matter after 36 h, while only 8.2×109 c.f.u. g–1 substrate dry matter was obtained in a static tray system. 相似文献
995.
Microbial biomass and nitrogen cycling responses to fertilization and litter removal in young northern hardwood forests 总被引:15,自引:1,他引:14
The influence of site fertility on soil microbial biomass and activity is not well understood but is likely to be complex because of interactions with plant responses to nutrient availability. We examined the effects of long-term (8 yr) fertilization and litter removal on forest floor microbial biomass and N and C transformations to test the hypothesis that higher soil resource availability stimulates microbial activity. Microbial biomass and respiration decreased by 20–30 % in response to fertilization. Microbial C averaged 3.8 mg C/g soil in fertilized, 5.8 mg C/g in control, and 5.5 mg C/g in litter removal plots. Microbial respiration was 200 µg CO2-C g–1 d–1 in fertilized plots, compared to 270 µg CO2-C g–1 d–1 in controls. Gross N mineralization and N immobilization did not differ among treatments, despite higher litter nutrient concentrations in fertilized plots and the removal of substantial quantities of C and N in litter removal plots. Net N mineralization was significantly reduced by fertilization. Gross nitrification and NO3
– immobilization both were increased by fertilization. Nitrate thus became a more important part of microbial N cycling in fertilized plots even though NH4
+ availability was not stimulated by fertilization.Soil microorganisms did not mineralize more C or N in response to fertilization and higher litter quality; instead, results suggest a difference in the physiological status of microbial biomass in fertilized plots that influenced N transformations. Respiration quotients (qCO2, respiration per unit biomass) were higher in fertilized plots (56 µg CO2-C mg C–1 d–1) than control (48 µg CO2-C mg C–1 d –1) or litter removal (45 µg CO2-C mg C–1 d–1), corresponding to higher microbial growth efficiency, higher proportions of gross mineralization immobilized, and lower net N mineralization in fertilized plots. While microbial biomass is an important labile nutrient pool, patterns of microbial growth and turnover were distinct from this pool and were more important to microbial function in nitrogen cycling. 相似文献
996.
997.
998.
999.
Three-year-old plants of Parthenium argentatum Gray cv. 11591 grown under natural photoperiod were exposed for 60 d to low night temperature (LNT) of 15 °C (daily from
18:00 to 06:00). Effects of the treatment on net photosynthetic rates (P
N), rubber accumulation, and associated biochemical traits were examined. LNT initially reduced P
N with a parallel decline in the activities of ribulose-1,5-bisphosphate carboxylase, fructose bisphosphatase, and sucrose
phosphate synthase for 20–30 d. Later, LNT enhanced P
N and the activities of photosynthetic enzymes. Associated with high P
N in LNT-treated guayule plants was a two-fold increase in rubber content and rubber transferase activity per unit of protein.
The initial decrease in P
N in LNT-treated guayule was associated with low content of chlorophyll (a+b), large starch accumulation, and higher ratio of glucose-6-phosphate/fructose-6-phosphate. Photosystem 2 activity in isolated
chloroplasts was initially decreased, but increased after 30 d. There was a significant increase in the leaf soluble protein
content in LNT-treated plants. Hence the photosynthetic performance of plants grown at 15 °C night temperature for 50 d was
superior to those grown under natural photoperiod in all parameters studied. The high photosynthetic capacity may contribute
to superior rubber yields under LNT.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
1000.
Photosynthetic Characteristics of Non-Leaf Organs of Winter Wheat Cultivars Differing in Ear Type and their Relationship with Grain Mass Per Ear 总被引:11,自引:0,他引:11
Chlorophyll content, photosystem 2 functioning (Fv/Fm, Fv/F0), activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, and net photosynthetic rates (P
N) of flag leaf blade, sheath, peduncle, and ear organs were assessed in large-ear type (Pin 7) and small-ear type (ND93) wheat cultivars. Some differences were found in photosynthetic properties between different green plant parts, the values of all studied parameters in ear parts being higher in Pin7 than in ND93. Furthermore, ear surface areas and ear P
N in 26 wheat genotypes measured at anthesis showed highly significant positive correlation with grain mass per ear. Hence a greater capability of ear photosynthesis may result in a greater grain yield in large-ear type cultivars. 相似文献