[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yel...[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yellow, blue and purple films to obtain different light quality, the changes of chlorophyll content, activity and gene expression of caspase-like proteases in the tobacco leaves were studied. [Results] Compared with treatments of white, red and yellow film, blue and purple films delayed the decrease of chlorophyll content and senescence of tobacco leaves at the late growth stage, and relatively lowered the activity and gene expression of caspase-like proteases during growth, development and senescence periods. [Conclusion] Different light qualities exhibited various effects on the growth, development and senescence of tobacco leaves, possibly by affecting the activity and gene expression of caspase-like proteases to some extent.展开更多
Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coup...Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.展开更多
The current study was to investigate the effects of cysteamine （CS） on carcass characteristics, meat quality, and antioxidant status in finishing pigs. A total of 24 crossbred （PIC variety） finishing pigs （60.05&...The current study was to investigate the effects of cysteamine （CS） on carcass characteristics, meat quality, and antioxidant status in finishing pigs. A total of 24 crossbred （PIC variety） finishing pigs （60.05±1.24 kg, 12 gilts and 12 barrows） were assigned randomly to one of the three dietary groups, with four pens/group （one gilt and one barrow per pen）. Pigs were fed with a basal diet containing 0 （control）, 70, or 140 mg/kg CS for 47 days. The results indicated that dietary CS supplementation increased （P〈0.05） the average daily gain and feed intake with optimal responses occurring at 70 mg/kg. Dietary supplementation of CS increased （P〈0.05） the dressing percentage and lean percentage of finishing pigs with optimal responses occurring at 140 mg/kg. The CS supplementation, however, had no effect （P〉0.05） on meat quality. Dietary CS supplementation increased （P〈0.05） total antioxidant capacity （T-AOC） and decreased malondialdehyde （MDA） with optimal responses occurring at 70 mg/kg. CS supplementation at both 70 mg/kg and 140 mg/kg doses improved （P〈0.05） the muscle RNA/DNA ratio. Collectively, the results suggest dietary supplementation of 70 mg/kg CS could significantly improve growth performance and antioxidant status without adverse effects on the gastrointestinal tracts in finishing pigs while the 140 mg/kg CS supplementation improved the carcass quality. However, meat quality was not affected by CS supplementation.展开更多
Large amount of pre-plant nitrogen （N） fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the st...Large amount of pre-plant nitrogen （N） fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the study were to compare growth and yield of maize （Zea rnays L.） under conventional and site-specific N management in a dryland farming system. The study, which was designed as randomized complete block design was conducted over three site-years under continuous maize cropping system in the semi-arid regions of the Limpopo Province in South Africa. Treatments of the study consisted of three N management strategies on a maize field planted to drought resistant SNK 2147 hybrid maize cultivar. Treatments were： （i） no N application （NO）, （ii） site-specific N at variable rates ranging between 18 kg N/ha and 33 kg N/ha based on soil analysis results （N l） and （iii） conventional and uniform N application broadcasted during planting at 58 kg N/ha （N2）. Sufficiency index as indication of N deficiency was determined using CCM-200 on maize leaves based on leaf numbers during maize vegetative growth stages V6, V10 and Vl4, and thereafter N was applied only when needed. The highest maize grain yield of 5.2 Mg/ha for N 1 was significantly higher （P 〈 0.05） than 3.2 Mg/ha and 4.0 Mg/ha of N0 and N2 in site-year I, respectively. Maize grain yield of 2.2 Mg/ha （Nl） at site-year ll was significantly higher （P _〈 0.05） than 1.7 Mg/ha of the NO. The maize growth and yield under N2 and N1 was compared, N1 required between 43% and 69% lesser N fertilizer as compared to N2 over site-years, and resulted in higher maize height, number of leaves per plant, leaf length, and leaf area than that of conventional N management strategy. Therefore, site-specific N management strategy sustains and improves growth and yield of maize using minimal N fertilizer as compared to conventional approach in low fertility soils of semi-arid regions in dryland farming systems. In examining the results of this study, there was a consistent benefit of site-specific N management strategy on improving growth and yield of maize while saving fertilizer use in small-scale dryland maize farming system.展开更多
基金Supported by National Natural Science Foundation of China(30460016)Science and Technology Plan from Yunnan Branch Office of China National Tobacco Corporation(2011YN03,2010YN03,07A01)~~
文摘[Objective] The study aimed to investigate the activity and gene expression of caspase-like proteases in tobacco leaves growing under different light qualities. [Method] By covering tobacco plants with white, red, yellow, blue and purple films to obtain different light quality, the changes of chlorophyll content, activity and gene expression of caspase-like proteases in the tobacco leaves were studied. [Results] Compared with treatments of white, red and yellow film, blue and purple films delayed the decrease of chlorophyll content and senescence of tobacco leaves at the late growth stage, and relatively lowered the activity and gene expression of caspase-like proteases during growth, development and senescence periods. [Conclusion] Different light qualities exhibited various effects on the growth, development and senescence of tobacco leaves, possibly by affecting the activity and gene expression of caspase-like proteases to some extent.
基金supported by the National High Technology Research and Development Program (863 Program) of China(No.2002AA2Z4321-02)
文摘Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.
文摘The current study was to investigate the effects of cysteamine （CS） on carcass characteristics, meat quality, and antioxidant status in finishing pigs. A total of 24 crossbred （PIC variety） finishing pigs （60.05±1.24 kg, 12 gilts and 12 barrows） were assigned randomly to one of the three dietary groups, with four pens/group （one gilt and one barrow per pen）. Pigs were fed with a basal diet containing 0 （control）, 70, or 140 mg/kg CS for 47 days. The results indicated that dietary CS supplementation increased （P〈0.05） the average daily gain and feed intake with optimal responses occurring at 70 mg/kg. Dietary supplementation of CS increased （P〈0.05） the dressing percentage and lean percentage of finishing pigs with optimal responses occurring at 140 mg/kg. The CS supplementation, however, had no effect （P〉0.05） on meat quality. Dietary CS supplementation increased （P〈0.05） total antioxidant capacity （T-AOC） and decreased malondialdehyde （MDA） with optimal responses occurring at 70 mg/kg. CS supplementation at both 70 mg/kg and 140 mg/kg doses improved （P〈0.05） the muscle RNA/DNA ratio. Collectively, the results suggest dietary supplementation of 70 mg/kg CS could significantly improve growth performance and antioxidant status without adverse effects on the gastrointestinal tracts in finishing pigs while the 140 mg/kg CS supplementation improved the carcass quality. However, meat quality was not affected by CS supplementation.
文摘Large amount of pre-plant nitrogen （N） fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the study were to compare growth and yield of maize （Zea rnays L.） under conventional and site-specific N management in a dryland farming system. The study, which was designed as randomized complete block design was conducted over three site-years under continuous maize cropping system in the semi-arid regions of the Limpopo Province in South Africa. Treatments of the study consisted of three N management strategies on a maize field planted to drought resistant SNK 2147 hybrid maize cultivar. Treatments were： （i） no N application （NO）, （ii） site-specific N at variable rates ranging between 18 kg N/ha and 33 kg N/ha based on soil analysis results （N l） and （iii） conventional and uniform N application broadcasted during planting at 58 kg N/ha （N2）. Sufficiency index as indication of N deficiency was determined using CCM-200 on maize leaves based on leaf numbers during maize vegetative growth stages V6, V10 and Vl4, and thereafter N was applied only when needed. The highest maize grain yield of 5.2 Mg/ha for N 1 was significantly higher （P 〈 0.05） than 3.2 Mg/ha and 4.0 Mg/ha of N0 and N2 in site-year I, respectively. Maize grain yield of 2.2 Mg/ha （Nl） at site-year ll was significantly higher （P _〈 0.05） than 1.7 Mg/ha of the NO. The maize growth and yield under N2 and N1 was compared, N1 required between 43% and 69% lesser N fertilizer as compared to N2 over site-years, and resulted in higher maize height, number of leaves per plant, leaf length, and leaf area than that of conventional N management strategy. Therefore, site-specific N management strategy sustains and improves growth and yield of maize using minimal N fertilizer as compared to conventional approach in low fertility soils of semi-arid regions in dryland farming systems. In examining the results of this study, there was a consistent benefit of site-specific N management strategy on improving growth and yield of maize while saving fertilizer use in small-scale dryland maize farming system.
