家蚕病毒的表面增强拉曼光谱研究

得到并分析了家蚕核型多角体病毒（ＢｏｍｂｙｘｍｏｒｉＮｏｃｌｅａｒＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓ缩写为ＢｍＮＰＶ）和质型多角体病毒（ＢｏｍｂｙｘｍｏｒｉｃｙｔｏｐｌａｓｍｉｃＰｏｌｙｈｅｄｒｏｓｉｓＶｉｒｕｓ缩写为ＢｍＣＰＶ）包涵体（即核型多角体ＢｍＮＰＢ和质型多角体ＢｍＣＰＢ）在银胶溶液中的表面增强拉曼散射（ＳＥＲＳ）光谱。ＢｍＮＰＢ和ＢｍＣＰＢ通过氨基酸残基侧链的Ｓ原子、ＣＯＯ－（ＣＯＯＨ）和ＮＨ２（ＮＨ）基团以及蛋白质分子的Ｎ－末端与银表面相作用。Ｔｒｐ残基金部或大部处于疏水环境中。ＢｍＮＰＢ中蛋氨酸残基侧链的Ｓ－ＣＨ２和ＣＨ２－ＣＨ２链分别为扭曲和扭曲式构型。ＢｍＣＰＢ中的Ｓ－ＣＨ２和ＣＨ２－ＣＨ２链则分别属于反式和扭曲构型;Ｃ－Ｃ－Ｓ－Ｓ－Ｃ－Ｃ链为反式－扭曲－反式结构。     

重庆地区“双千田”组合模式及效益分析

重庆地区“双千田”组合模式及效益分析郑钦玉,朱自均,胡声荣,袁可（西南农业大学,重庆６３０７１６）雷炎,李登国,程世宇,温永学,刘官堂（四川省巴县农业局）ＣｏｍｂｉｎａｔｉｏｎＭｏｄｅｌｓｏｆ＂ＴｏｎＧｒａｉｎＹｉｅｌｄｉｎｇＦｉｅｌｄ＂ｉｎＣｈｏｎｇｑｉｎｇＡｒｅａａｎｄＴｋｅｉｒＢｅｎｅｆｉｔＡｎａｌｙｓｉｓ￥．ＺｈｅｎｇＱｉｎｙｕ;ＺｈｕＺｈｉｊｕｎ;ＨｕＳｈｅｎｇｒｏｎｇ;ＹｕａｎＫｅ（ＳｏｕｔｈｗｅｓｔＡｇｒｉｃｕｌｔｕｒａｌＵｎｉｖｅｒｓｉｔｙ,Ｃｈｏｎｇｑｉｎｇ６３０７１６）,ＬｅｉＹａｎ,ＬｉＤｅｎｇｇｕｏ,ＣｈｅｎｇＳｈｉｙｕ,ＷｅｎＹｏｎｇｘｕｅ,ＬｉｕＧｕａｎｔａｎｇ（ＢａｘｉａｎＢｕｒｅａｕｏｆＡｇｒｉｃｕｌｔｕｒｅ,ＳｉｃｈｕａｎＰｒｏｖｉｎｃｅ）．ＣｈｉｎｅｓｅＪｏｕｍａｌｏｆＥｃｏｌｅｇｙ,１９９３,１２（２）：３４—３６．Ｉｎｔｈｅｌｉｇｈｔｏｆｔｈｅｅｆｆｅｃｔｓａｎｄｐｒｏｂｌｅｍｓｏｆｄｅｖｅｌｏｐｉｎｇｗｉｎｔｅｒ－ｃｒｏｐｐｉｎｇｐａｄｄｙｆｉｅｌｄｓｉｎＣｈｏｎｇｑｉｎｇａｒｅａａｎｄｉｎｏｒｄｅｒｔｏｓｅａｒｃｈａｆｔｅｒｔｈｅｏｐｔｉｍｕｍｍｏｄｅｌｏｆｒｅｆ     

从睡眠剥夺树鼩（TBC）尿液提取内源性“睡眠因子”（sleep factor）的研究

本研究报道从睡眠剥夺（ＳＤ）４８—７２ｈ的灵长类原宗（ｐｒｉｍｉｔｉｖｅｓｔｏｃｋ）Ｔｕｐａｉａｂｅｌａｎｇｅｒｉｃｈｉｎｅｎｓｉｓ（ＴＢＣ）提取内源性“睡眠因子”（ｓｌｅｅｐｆａｃｔｏｒ）Ｓ２Ｃ和Ｓ４Ｂ。收集的尿液经超滤,清液冻干经ＳｅｐｈａｄｅｘＧ１５分离得到ＦｒａｃｔｉｏｎⅠ－Ⅴ。活性测定发现Ｆｒａｃｔｉｏｎ－Ⅲ（Ｓ２Ｃ）呈现显著δ－增强促眠效应。经ＳｅｐｈａｄｅｘＧ２５和ＳｅｐｈａｄｅｘＬＨ２０进一步净化的Ｓ４Ｂ也呈现显著δ－增强促眠效应。     

曲周县畜牧业规模效益分析

曲周县畜牧业规模效益分析曹志平（北京农业大学生物学院１０００９４）ＢｅｎｅｆｉｔＡｎａｌｙｓｉｓｏｎＡｎｉｍａｌＨｕｓｂａｎｄｒｙＳｃａｌｅｓｉｎＱｕｚｈｏｕＣｏｕｎｔｙ￥．ＣａｏＺｈｉｐｉｎｇ（ＣｏｌｌｅｇｅｏｆＢｉｏｌｏｇｙ,ＢｅｉｊｉｎｇＡｇｒ...     

农业系统生产力（ASP）的量化及其现状分析

农业系统生产力（ＡＳＰ）的量化及其现状分析卢进登,韩纯儒（北京农业大学农学系,１０００９４）ＱｕａｎｔｉｆｉｃａｔｉｏｎｏｆＡｇｒｏｓｙｓｔｅｍＰｒｏｄｕｃｔｉｖｉｔｙ（ＡＳＰ）ａｎｄＡｎａｌｙｓｉｓｏｎｉｔｓＣｕｒｒｅｎｔＳｉｔｕａｔｉｏｎｉｎＣｂｉｎａ￥．ＬｕＪｉｎ－ｄｅｎｇ;ＨａｎＣｈｕｎｒｕ（ＢｅｉｊｉｎｇＡｇｒｉｃｕｌｔｕｒａｌＵｎｉｖｅｒｓｉｔｙｆＢｅｉｊｉｎｇ１０００９４）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：２１－２２．ＢａｓｅｄｏｎａｂｒｉｅｆａｎａｌｙｓｉｓｏｎｔｈｅｆｏｒｍａｔｉｏｎｐｒｏｃｅｓｓｏｆＡＳＰ,ｉｔｓｃｏｎｃｅｐｔｉｓｄｅｓｃｒｉｂｅｄａｎｄａｎｉｎｔｅｇｒａｔｅｄｉｎｄｉ－ｃａｔｏｒｆｏｒｉｔｓｑｕａｎｔｉｆｉｃａｔｉｏｎ—ＡＳＰ２ｉｓｐｕｔｆｏｒｗａｒｄｓ．Ｆｒｏｍｔｈｏｓｅ,ｔｈｅＡＳＰｌｅｖｅｌｓｉｎｖａｒｉｏｕｓｒｅｇｉｏｎｓｏｆＣｈｉｎａａｒｅａｎａｌｙｚｅｄａｎｄ８ｌｅｖｅｌｓａｒｅｄｉｖｉｄｅｄｂｙｕｓｉｎｇ．Ｈｉｅｒａｒｃｈｉｃｃｌｕｓｔｅｒｉｎｇｍｅｔｈｏｄ．Ｉｔ’ｓ：ｃｌａｒｉｆｉｅｄｔｈａｔＡＳ－ＰＩｉｓａｍｏｒｅ     

International Young Life Scientist Programme

Ａｔｔｈｅ１８ｔｈＩｎｔｅｒｎａｔｉｏｎａｌＣｏｎｇｒｅｓｓｏｆＢｉｏｃｈｅｍｉｓｔｒｙａｎｄＭｏｌｅｃｕｌａｒＢｉｏｌｏｇｙ,Ｂｉｒｍｉｎｇｈａｍ,ＥｎｇｌａｎｄＴｈｅＩｎｔｅｒｎａｔｉｏｎａｌＵｎｉｏｎｏｆＢｉｏｃｈｅｍｉｓｔｒｙａｎｄＭｏｌｅｃｕｌａｒＢｉｏｌｏｇｙ（ＩＵＢＭＢ）,ｔｈｅＦｅｄｅｒａｔｉｏｎｏｆＥｕｒｏｐｅａｎＢｉｏｃｈｅｍｉｃａｌＳｏｃｉｅｔｉｅｓ（ＦＥＢＳ）,ａｎｄｔｈｅＢｉｏｃｈｅｍｉｃａｌＳｏｃｉｅｔｙａｎｎｏｕｎｃｅｔｈｅｓｐｏｎｓｏｒｓｈｉｐｏｆａＳｙｍｐｏｓ…     

日本血吸虫26kD抗原基因在BCG中的表达

研究了外源基因日本血吸虫２６ｋＤ抗原（Ｓｊ２６ＧＳＴ）在卡介苗（ｂａｃｉｌｕｓＣａｌｍｅｔｅ－Ｇｕｅｒｉｎ,ＢＣＧ）、耻垢分枝杆菌（Ｍ．ｓｍｅｇｍａｔｉｓ）和大肠杆菌（Ｅ．ｃｏｌｉ）中的表达．运用重组ＤＮＡ和聚合酶链反应（ＰＣＲ）等分子生物学技术,以表达Ｓｊ２６ＧＳＴ的Ｅ．ｃｏｌｉｐＧＥＸ衍生质粒为模板,经ＰＣＲ得到编码Ｓｊ２６ＧＳＴ的全长ｃＤＮＡ片段．将其按正确的阅读框顺序,克隆到人结核杆菌热休克蛋白（ｈｅａｔｓｈｏｃｋｐｒｏｔｅｉｎ,ＨＳＰ）７０的启动子下游,再将ＨＳＰ７０启动子和Ｓｊ２６ＧＳＴ基因一起亚克隆到Ｅ．ｃｏｌｉ－分枝杆菌穿梭质粒ｐＢＣＧ－２０００中,得到Ｅ．ｃｏｌｉ－分枝杆菌穿梭表达质粒ｐＢＣＧ－Ｓｊ２６．ｐＢＣＧ－Ｓｊ２６电转化入ＢＣＧ和Ｍ．ｓｍｅｇｍａｔｉｓｍｃ２１５５中表达Ｓｊ２６ＧＳＴ抗原,所表达的天然重组Ｓｊ２６ＧＳＴ（ｒＳｊ２６ＧＳＴ）为可溶性蛋白,在ＳＤＳ－ＰＡＧＥ上分子量为２６ｋＤ处可见明显的表达蛋白带．其表达量分别占ＢＣＧ和Ｍ．ｓｍｅｇｍａｔｉｓ菌体总蛋白的１５％和１０％．可见,Ｓｊ２６ＧＳＴ基因能在ＢＣＧ中高效表达．     

Conformational Studies of Arabinoglucuronomannology (AGM)

ＣｏｎｆｏｒｍａｔｉｏｎａｌＳｔｕｄｉｅｓｏｆＡｒａｂｉｎｏｇｌｕｃｕｒｏｎｏｍａｎｎｏｌｏｇｙ（ＡＧＭ）ＩｍｓｈｉｋＬｅｅ;ＢａｉＣｈｕｎｌｉ;ＷａｎｇＣｈｅｎ（ＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｓｔｒｙ,ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃ...     

中国兰科植物新资料

本文报道了２个新种（元阳石豆兰ＢｕｌｂｏｐｈｙｌｌｕｍｙｕａｎｙａｎｇｅｎｓｅＴｓｕｉ,长帽隔距兰ＣｌｅｉｓｏｓｔｏｍａｌｏｎｇｉｏｐｅｒｃｕｌａｔｕｍＴｓｉ）、２个新组合（翼萼卷瓣兰ＢｕｌｂｏｐｈｙｌｌｕｍｒｅｔｕｓｉｕｓｃｕｌｕｍＲｃｈｂ．ｆ．ｖａｒ．ｏｒｅｏｇｅｎｅｓ（Ｗ．Ｗ．Ｓｍｉｔｈ）Ｔｓｉ,角萼卷瓣兰Ｂ．ｒｅｔｕｓｉｕｓｃｕｌｕｍＲｃｈｂ．ｆ．ｖａｒ．ｔｉｇｒｉｄｕｍ（Ｈａｎｃｅ）Ｔｓｉ）和１个新命名（细茎毛兰ＥｒｉａｔｅｎｕｉｃａｕｌｉｓＳ．Ｃ．ＣｈｅｎｅｔＴｓｉ）。     

柞蚕林生物生产力和干物质转化研究

柞蚕林生物生产力和干物质转化研究温达志,杨思河（中国科学院华南植物研究所,广州５１０６５０）（中国科学院沈阳应用生态研究所,１１００１５）姜波（辽宁省蚕业科学研究所,凤城１１８１０１）ＢｉｏｐｒｏｄｕｃｔｉｖｉｔｙａｎｄＤｒｙＭａｔｔｅｒＴｒａｎｓｆｅｒｏｆＴｕｓｓａｈ－ＦｅｅｄｉｎｇＯａｋＦｏｒｅｓｔ￥ＷｅｎＤａｚｈｉ（ＳｏｕｔｈＣｈｉｎａＩｎｓｔｉ－ｔｕｔｅｏｆＢｏｔａｎｙ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｇｕａｎｇｚｈｏｕ５１０６５０）,ＹａｎｇＳｉｈｅ（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＥｃｏｌｏｇｙ,Ａ－ｃａｄｅｍｉａＳｉｎｉｃａ,Ｓｈｅｎｙａｎｇ１１００１５）,ＪｉａｎｇＢｏ（ＩｎｓｔｉｔｕｔｅｏｆＳｅｒｉｃｕｌｔｕｒａｌＳｃｉｅｎｃｅ,Ｆｅｎｇｃｈｅｎｇ,ＬｉａｏｎｉｎｇＰｒｏｖｉｎｃｅ１１３１００）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（１）：５－１０．ＴｈｅｐｒｅｓｅｎｔｓｔｕｄｙｄｅａｌｓｗｉｔｈｔｈｅｂｉｏｐｒｏｄｕｃｔｉｖｉｔｙａｎｄｄｒｙｍａｔｔｅｒｔｒａｎｓｆｅｒｏｆＣｈｉｎｅｓｅＴｕｓｓａｈ－ｆｅｅｄｉｎｇｏａｋｆｏｒｅｓｔｉｎｈｉｌｌｙａｒｅａｏｆｅ     

Some factors governing rice-ratoon yields

Summary Studies on rice ratooning showed that the height of cutting the main crop affected the maturity period and the yield of the ratoon. The ratoon yield was significantly higher when the main crop was cut at ground level versus cutting at 4,8 and 12 cm high, but the maturity period was lower with a higher cutting. Delaying first watering for 4 to 8 days was superior to watering a day after the harvest of the main crop. The ratoon yield was about 14 per cent higher than the planted crop.     

Response of eight sugarcane cultivars to glyphosine and glyphosate ripeners

Studies were conducted on eight sugarcane (Saccharum spp. hydrid) cultivars during the 1982–83 (plant crop) and 1983–84 (ratoon crop) growing seasons to determine the effects of glyphosine (Polaris) (N,N-bis (phosphonomethyl) glycine) and glyphosate (Polado) (sodium-N-(phosphonomethyl) glycine) on stalk sucrose content and yield. Difference due to crops (plant vs. ratoon) for sugarcane quality, kilograms of sugar per ton of cane (S/T), sugarcane yield, tons of cane per hectare (TCH), and sugar yield, tons of sugar per hectare (TSH) were significant. Significant differences were found in quality for the ratoon crop and cane and sugar yield in both crops due to ripener treatment. Cultivars in both crops differed significantly in quality and yield. Harvest dates were significantly different for all plant characteristics. Interactions of cultivar by treatment for the plant crop, harvest date by treatment for the ratoon crop, and cultivar by harvest date for both crops for cane quality also were significant. Time from ripener application to achievement of maximum sugar concentration also depended on cultivar. This is important in determining the economic benefits of a ripener treatment. Climatic conditions may also affect the benefits of such applications.     

Response of eight sugarcane cultivars to glyphosine and glyphosate ripeners

Studies were conducted on eight sugarcane (Saccharum spp. hydrid) cultivars during the 1982–83 (plant crop) and 1983–84 (ratoon crop) growing seasons to determine the effects of glyphosine (Polaris) (N,N-bis (phosphonomethyl) glycine) and glyphosate (Polado) (sodium-N-(phosphonomethyl) glycine) on stalk sucrose content and yield. Difference due to crops (plant vs. ratoon) for sugarcane quality, kilograms of sugar per ton of cane (S/T), sugarcane yield, tons of cane per hectare (TCH), and sugar yield, tons of sugar per hectare (TSH) were significant. Significant differences were found in quality for the ratoon crop and cane and sugar yield in both crops due to ripener treatment. Cultivars in both crops differed significantly in quality and yield. Harvest dates were significantly different for all plant characteristics. Interactions of cultivar by treatment for the plant crop, harvest date by treatment for the ratoon crop, and cultivar by harvest date for both crops for cane quality also were significant. Time from ripener application to achievement of maximum sugar concentration also depended on cultivar. This is important in determining the economic benefits of a ripener treatment. Climatic conditions may also affect the benefits of such applications.Mention of trade name or proprietary product does not imply or constitute an endorsement or recommendation by the USDA or the University of Florida.     

Response of rice to different forms of urea and phosphorus fertilization under intermediate deepwater conditions (15–50 cm)

Summary Under intermediate deepwater condition with water depths of 15–35 cm during most of the crop growth period, sulphur coated urea and urea supergranule placement was superior to prilled urea in increasing the relative uptake and grain yield (23–25%) of rice. A semi-tall variety (CR 1016) responded better to the nitrogen application than a tall variety (CR 1030).The crop fertilized with N produced more number of tillers and grain yield than the unfertilized crop under complete submergence for 6 days at seedling establishement stage (8 days after transplanting) followed by waterlogging of 25±5 cm throughout the crop growth period. Application of phosphorus together with nitrogen increased the grain yield (9–14%) over nitrogen alone. Crop fertilized with these two nutrients (NP) increased their uptake and yield components.     

The effect of Banana streak virus on the growth and yield of dessert bananas in tropical Australia

We have examined the effect of a strain of Banana streak virus (BSV‐Cav) on the growth and yield of dessert bananas (Musa AAA group, Cavendish subgroup cv. Williams) in north Queensland, Australia. Healthy and infected plants were compared in a replicated field experiment over plant and first ratoon crops. In both crops, symptom expression followed a similar pattern, increasing to a maximum near the estimated time of bunch initiation, then decreasing in the period prior to bunch emergence. There was no evidence of plant‐to‐plant spread of virus, but the rate of transmission through suckers was 100%. In the plant crop, the mean bunch weights of healthy and infected plants were not significantly different. However, BSV‐Cav infection resulted in an 18 day delay in harvest, causing a 6% reduction in yield per annum. In the ratoon crop, the mean bunch weight of infected plants was 7% less than that of healthy plants, and the interval between the harvest of plant and ratoon crops was delayed by 9 days, resulting in a 11% reduction in yield per annum. Also, the mean length of fruit from infected plants was 5% less than that of healthy plants, resulting in a smaller percentage of fruit in the extra large size category. We conclude that in horticulturally favourable conditions typical of the tropical Australian banana industry, the effects of BSV‐Cav infection on the growth and yield of Cavendish bananas are small.     

Twig pre-harvest temperature significantly influences effective cryopreservation of Vaccinium dormant buds

Cryopreservation of temperate woody-plant material by dormant buds is less expensive than using shoot tips isolated from tissue cultured plants; however currently, dormant buds are used only for preservation of selected temperate tree and shrub species. Using dormant buds could be an efficient strategy for long-term preservation of blueberry (Vaccinium L.) genetic resources. In this study, viability of V. hybrid ‘Northsky’ (PI 554943) dormant buds was evaluated at 30 harvest dates over three consecutive fall/winter seasons to determine the optimal harvest time that promotes high post cryopreservation viability. Twigs with dormant buds were cut into 70 mm segments containing at least two nodes, desiccated, slowly cooled, stored in liquid nitrogen vapor and tested for post-cryopreservation regrowth. The highest regrowth of cryopreserved dormant buds was observed for buds harvested in mid-December and during the first half of January. Pearson's correlation coefficients were computed to evaluate the association between bud characteristics and viability at harvest date and logistic regression models were fit to test the ability of twig characteristics and temperatures to predict post cryopreservation bud viability. Post-cryopreservation viability was negatively correlated (p < 0.05) with average minimum, maximum and daily mean temperature preceding the bud harvest but was not correlated with the dormant bud initial and end moisture content, twig diameter, the number of dormant buds/cm of twig length and the number of days in desiccation. Regression tree analysis suggested post-cryopreservation viability to be between 52 and 80% for dormant buds harvested after a 10 day average maximum air temperature of <11.2 °C. Pre-harvest air temperature was a significant indicator of optimal dormant bud harvest time to produce adequate viability for long term preservation of blueberry genetic resources.     

Effects of nitrogen fertilizer applied before permanent flood on the interaction between rice and rice water weevil (Coleoptera: Curculionidae)

Nitrogen fertilizer was applied to rice, Oryza sativa L., before permanent flood to determine the interaction between rice and the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), through a series of experiments conducted over a 3-yr period in Texas and Louisiana. Both absolute and relative percentage of yield loss because of L. oryzophilus feeding was not affected by fertilizer rates in the Texas experiment. Absolute yield loss increased with nitrogen rates in 2001 and 2002 in the Louisiana experiment; however, percentage of yield loss was not affected. This finding suggests that nitrogen rate does not affect tolerance of rice to L. oryzophilus injury. In the Texas experiment, differences were detected for ratoon crop yield among nitrogen rates and insecticide that were applied at preflood on the main crop, indicating a carryover of fertilizer and insecticide effects from the main to the ratoon crop. L. oryzophilus populations tended to increase with nitrogen fertilizer in the Louisiana experiment. Our results show that farmers should not increase preflood nitrogen fertilizer to increase tolerance of rice to L. oryzophilus injury.     

Crop performance, nitrogen and water use in flooded and aerobic rice

Irrigated aerobic rice is a new system being developed for lowland areas with water shortage and for favorable upland areas with access to supplementary irrigation. It entails the cultivation of nutrient-responsive cultivars in nonsaturated soil with sufficient external inputs to reach yields of 70–80% of high-input flooded rice. To obtain insights into crop performance, water use, and N use of aerobic rice, a field experiment was conducted in the dry seasons of 2002 and 2003 in the Philippines. Cultivar Apo was grown under flooded and aerobic conditions at 0 and at 150 kg fertilizer N ha^–1. The aerobic fields were flush irrigated when the soil water potential at 15-cm depth reached –30 kPa. A ¹⁵N isotope study was carried out in microplots within the 150-N plots to determine the fate of applied N. The yield under aerobic conditions with 150 kg N ha^–1 was 6.3 t ha^–1 in 2002 and 4.2 t ha^–1 in 2003, and the irrigation water input was 778 mm in 2002 and 826 mm in 2003. Compared with flooded conditions, the yield was 15 and 39% lower, and the irrigation water use 36 and 41% lower in aerobic plots in 2002 and 2003, respectively. N content at 150 kg N ha^–1 in leaves and total plant was nearly the same for aerobic and flooded conditions, indicating that crop growth under aerobic conditions was limited by water deficit and not by N deficit. Under aerobic conditions, average fertilizer N recovery was 22% in both the main field and the microplot, whereas under flooded conditions, it was 49% in the main field and 36% in the microplot. Under both flooded and aerobic conditions, the fraction of ¹⁵N that was determined in the soil after the growing season was 23%. Since nitrate contents in leachate water were negligible, we hypothesized that the N unaccounted for were gaseous losses. The N unaccounted for was higher under aerobic conditions than under flooded conditions. For aerobic rice, trials are suggested for optimizing dose and timing of N fertilizer. Also further improvements in water regime should be made to reduce crop water stress.     

Accelerated Early Growth of Rice at Elevated CO2 (Is It Related to Developmental Changes in the Shoot Apex?)

The influence of elevated CO2 on the development of the shoot apex and on subsequent vegetative growth and grain yield was investigated using rice (Oryza sativa L. cv Jarrah) grown in flooded soil at either 350 or 700 [mu]L CO2 L-1. At 8 d after planting (DAP), elevated CO2 increased the height and diameter of the apical dome and lengths of leaf primordia and tiller buds but had no effect on their numbers. By 16 DAP, there were five tiller buds in the apex at 700 [mu]L CO2 L-1 compared with only three tiller buds at 350 [mu]L CO2 L-1. These changes in development of the shoot apex at high CO2 were forerunners to faster development of the vegetative shoot at elevated CO2 between 11 and 26 DAP as evidenced by increases in the relative growth rates of the shoot and tillers. Accelerated development at high CO2 was responsible for the 42% increase in tiller number at the maximum tillering stage and the 57% enhancement of grain yield at the final harvest. The link between high CO2 effects on development during the first 15 DAP and final tiller number and grain yield was demonstrated by delaying exposure of plants to high CO2 for 15 d. The delay totally inhibited the tillering response to high CO2, and the increase in grain yield of 20% arose from a greater number of grains per panicle. Consequently, it can be concluded that accelerated development in the shoot apex early in development is crucial for obtaining maximum increases in grain yield at elevated atmospheric CO2 concentrations.     

Effect of soil sodicity on the growth,yield and chemical composition of groundnut (Arachis hypogaea Linn.)

Summary A replicated field experiment was conducted to study the effect of exchangeable sodium percentage (ESP) on the yield, chemical composition, protein and oil content and uptake of nutrients by groundnut (Arachis hypogaea Linn.) variety M-13. ESP over 15 delayed germination and emergence of flowers. There was continuous decrease in dry matter yield at 30 and 60 days of growth, grain and straw yield after harvest and protein, oil and kernel percent with increase in soil ESP. A 50 per cent reduction in groundnut yield was observed at an ESP of 20. Increasing soil ESP, increased Na and decreased K, Ca and N contents, but had no effect on the Mg, P, S, Fe, Mn, Zn and Cu contents of the plant. Sodium content of the plant increased, while potassium and nitrogen decreased with age of the plant. The uptake of all the nutrients decreased with increase in soil ESP. The results showed that groundnut is a relatively sensitive crop to soil sodicity.