Cassava is vulnerable to frost and snow, so it is suitable for planting in tropical and subtropical region. Low temperature is an important environment factor affecting the growth and development and production of cas...Cassava is vulnerable to frost and snow, so it is suitable for planting in tropical and subtropical region. Low temperature is an important environment factor affecting the growth and development and production of cassava, and the region with annual average temperature below 15 ℃ is not conducive to its normal growth and development. The improvement of cold resistance of cassava can increase the planting area and improve the yield and quality of cassava. In this study, morphological,physiological and biochemical and molecular researches on cold resistance of cassava, as well as the latest research progress,were reviewed in this paper. At the same time, some potential difficulties in the research on cold resistance of cassava were put forward, and the future work focus was also discussed.展开更多
Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects ...Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects on growth, development, yield components, yield and oil content of safflower. Increasing safflower plant density from 100,000 to 250,000 plants ha^- significantly reduced plant height （13.2%-21.3%）, branch number plant^-1 （37%-54.7%）, leaf number plant^-1 （39%-39.2%）, leaf area （19.5%-53%）, plant spread （39.6%-54.4%）, root length （28.1%-54.4%）, plant biomass （17%-50%）, capitula size （12%-12.7%）, capitula number plant^-1 （39.5%-50.5%）, seed number capitula~ （39%-45%）, capitula weight （3.3%-3.6%）, seed yield （67.9%-69.8%） and seed oil content （14.7%-20.8%）. The reduction in vegetative growth, yield components, yield and oil content of safflower due to increased plant density was attributed to inter and intra-plant competition for light, nutrients and water necessary for growth and development. The differences between winter and summer grown safflower were attributed to difference in day and night temperature （DIF） and the average daily temperature which were optimum for safflower growth in winter. It was concluded that under Botswana conditions or in semi-arid areas, safflower should be planted at 50 cm × 20 cm or wider in order to maximize yield and oil content and allow the plants to express their maximum genetic potential.展开更多
文摘能谱处理算法是提升探测系统能量分辨率的重要方法之一。其中,种子局部平均(seeded localized averaging,SLA)算法是一种比较新颖的处理算法,采用平均计算的方式对多个道址的信号进行处理输出,但在处理对称双峰及偏峰时会出现峰位飘移及生成不存在的虚峰等问题。针对该问题通过赋予不同的权重、引入均值不等式和优化迭代参数等改进方法,提出了一种基于概率密度函数迭代的加权平均变换(weighted average transform,WAT)算法,利用概率密度函数模型描述探测器的随机输入信号,在对符合设定分布的随机输入信号累积处理过程中,利用加权平均的计算方式来处理信号。WAT算法保留了SLA算法原有的性质,还提高了非对称峰输入的能量分辨率,进一步提高了原始输入分布的适应性,解决了SLA算法处理时双峰输入后出现虚峰及重合峰等问题,偏峰处理将半高宽由741改善为435,峰位未飘移且未出现虚峰。利用WAT算法,对输入信号为高斯分布、对数高斯分布及多峰分布的情况进行数值模拟,验证了WAT算法用于能谱求解的有效性。
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-11-cssy)
文摘Cassava is vulnerable to frost and snow, so it is suitable for planting in tropical and subtropical region. Low temperature is an important environment factor affecting the growth and development and production of cassava, and the region with annual average temperature below 15 ℃ is not conducive to its normal growth and development. The improvement of cold resistance of cassava can increase the planting area and improve the yield and quality of cassava. In this study, morphological,physiological and biochemical and molecular researches on cold resistance of cassava, as well as the latest research progress,were reviewed in this paper. At the same time, some potential difficulties in the research on cold resistance of cassava were put forward, and the future work focus was also discussed.
文摘Two field trials were clone to evaluate the effects of plant density on the growth, development and yield of safflower. The results showed that plant density and season of growth had significant （P ≤ 0.01） effects on growth, development, yield components, yield and oil content of safflower. Increasing safflower plant density from 100,000 to 250,000 plants ha^- significantly reduced plant height （13.2%-21.3%）, branch number plant^-1 （37%-54.7%）, leaf number plant^-1 （39%-39.2%）, leaf area （19.5%-53%）, plant spread （39.6%-54.4%）, root length （28.1%-54.4%）, plant biomass （17%-50%）, capitula size （12%-12.7%）, capitula number plant^-1 （39.5%-50.5%）, seed number capitula~ （39%-45%）, capitula weight （3.3%-3.6%）, seed yield （67.9%-69.8%） and seed oil content （14.7%-20.8%）. The reduction in vegetative growth, yield components, yield and oil content of safflower due to increased plant density was attributed to inter and intra-plant competition for light, nutrients and water necessary for growth and development. The differences between winter and summer grown safflower were attributed to difference in day and night temperature （DIF） and the average daily temperature which were optimum for safflower growth in winter. It was concluded that under Botswana conditions or in semi-arid areas, safflower should be planted at 50 cm × 20 cm or wider in order to maximize yield and oil content and allow the plants to express their maximum genetic potential.
