两种除草剂对棉田节肢动物群落多样性指数的影响

系统地研究了棉田地面和棉株节肢动物群落及各亚群落施用克无踪(A)、高盖(B)与对照(CK)之间在群落生物多样性、丰富度和均匀度的差异.结果表明,对地面肉食动物群落生物多样性(H′)的A-CK的t值为3.099,B-CK的t值为2.449,t＞t_0.05=2.228,差异显著;地面植食动物亚群落的(H′)A-CK的t值为2.377,A-B为2.260,t＞t_0.05=2.228,差异均显著.棉株节肢动物群落及亚群落A-CK、B-CK和A-B之间差异不显著.地面节肢动物亚群落丰富度A-CK的t值为4.759,地面植食类节肢动物亚群落为4.359,地面肉食节肢动物亚群落为2.963,均t＞t0.0=2.228,表明A与CK之间差异显著;在均匀度上,A和B及A-CK、B与CK之间两类群落及亚群落上差异均不显著.A和B对棉株节肢动物群落影响很小.施用A和B及CK的生物多样性的变化总趋势一致.     

Simulation of shoot chloride accumulation: separation of physical and biochemical processes governing plant salt tolerance

The effect of growth under saline condition (100 mol m^-3 NaCl in the nutrient solution) on the influx and the efflux of glucose from roots of cotton plants was analysed utilising the non metabolisable glucose analogue [¹⁴C]-3-O-methylglucose ([¹⁴C]3-OMG). Apical segments (1 cm long) excised from cotton roots took up [¹⁴C]3-OMG. At each tested concentration (5–500 mmol m^-3), the influx was completely inhibited by the presence of the protonophore carbonylcyanide-m-chlorophenyl hydrazone (CCCP) indicating that it is mediated by a H⁺-coupled co-transport mechanism. The CCCP-sensitive [¹⁴C]3-OMG influx was lower in the root segments excised from plants grown on saline solution than in the controls, and this was particularly evident at lower external concentrations. This difference was not due to a lower H⁺ apoplastic availability. In fact, the saline condition did not affect the pH of the rhizosphere and indeed the H⁺–ATPase activity, evaluated in plasma membrane vesicles purified from saline-treated plants, was higher (+23%) than in the controls. The lower uptake of [¹⁴C]3-OMG into saline treated root segments was related to an enhanced value of the apparent K_m of the carrier for the glucose analogue. This effect is discussed in relation to either the more positive value of the transmembrane electric potential difference (ΔΨ) measured in these root segments, or a competitive inhibition of Na⁺ on the H⁺ binding site of the carrier. Growth in saline solution slightly affected the efflux of the [¹⁴C]3-OMG preloaded in root segments, changing the membrane permeability to the molecule. The results strongly suggest that the higher (2.5 fold) net exudation of glucose, observed in short-term (4 h) collection experiments, from roots of cotton plants grown in saline condition, is mainly due to an effect of the saline growth condition on the system involved in the reabsorption of the hexose rather than on its efflux. This revised version was published online in June 2006 with corrections to the Cover Date.     

High-frequency stable transformation of cotton (Gossypium hirsutum L.) by particle bombardment of embryogenic cell suspension cultures

Stable transformation of cotton (Gossypium hirsutum L.) at a high frequency has been obtained by particle bombardment of embryogenic cell suspension cultures. Transient and stable expression of the β-glucuronidase (GUS) gene was monitored in cell suspension cultures. Transient expression, measured 48 h after bombardment, was abundant, and stable expression was observed in over 4% of the transiently expressing cells. The high efficiency of stable expression is due to the multiple bombardment of rapidly dividing cell suspension cultures and the selection for transformed cells by gradually increasing the concentrations of the antibiotic Geneticin (G418). Southern analysis indicated a minimum transgene copy number of one to four in randomly selected plants. Fertile plants were obtained from transformed cell cultures less than 3 months old. However, transgenic and control plants from cell cultures older than 6 months produced plants with abnormal morphology and a high degree of sterility. Received: 20 January 1999 / Revision received: 1 October 1999 / Accepted: 11 October 1999     

施肥与摘蕾对棉蚜、棉叶蝉种群数量及棉花产量的影响

分析比较了不同施氮水平(0-450kg·hm^-2)与不同摘蕾处理(0-12个·株^-1)对转Bt基因棉花(GK-12)和常规棉花(泗棉3号)的棉蚜、棉叶蝉种群数量以及棉花产量的影响．结果表明,两个品种的棉蚜、棉叶蝉种群数量和有效铃量没有显著性差异。在本实验水平下,施肥和摘蕾与施肥的交互作用对两种棉花的棉蚜数量有显著性的影响,而摘蕾、施肥和两者的交互作用对两种棉花的棉叶蝉数量没有显著影响．在花铃期,施氮肥能增加两种棉花的有效铃数．线性回归分析表明,两种棉花的棉蚜、棉叶蝉的数量与施氮肥量和摘蕾量成正相关关系;有效铃量与施氮肥量呈正相关,与摘蕾量呈负相关．     

不同NH4^＋／NO3^-比例的氮素营养对棉花氮素代谢的影响

The influence of different NH4^+／NO3^- ratios on nitrogen metabolism of cotton was studied under controlled hydroponics, The results showed that compared with single nitrate nutrition, solutions with 25/75, 50/50, 75/25 and 100/0 of NH4^+／NO3^- significantly increased the soluble protein accumulation in leaves and roots of cotton, and the maximum content of soluble protein in leaves and roots appeared respectively in the solution with 50/50 and 75/25 of NH4^+／NO3^- The soluble protein content in roots was increased with the increase of NH4+ percentage, but was slightly less in the solution of 100/0 than 75/25, which was probably related to the excess NH4^+ limiting boot metabolism. With the increase of NH4+ percentage, the nitrate content in petiole and the nitrate reductase activity in functional blade declined, but ammoniac nitrogen content increased in every organ of cotton. These results showed that foreign nitrogen affected the nitrogen metabolism of cotton in a different way, and the nitrogen absorption by cotton was probably related to different forms of foreign nitrogen.     

氮肥对棉田主要害虫种群密度及棉花产量的影响

通过2年的田间研究,分析了3种不同施氮水平对棉花主要害虫棉玲虫、棉蚜种群动态、棉花蕾铃脱落及棉花产量的影响。结果表明,增施氮肥的棉田棉铃虫和棉蚜数量比对照田要高,但它们之间的差异没有达到显著的水平。不同年份对棉铃虫种群密度有显著影响,但对棉蚜种群没有显著影响。蕾花期施肥可减轻棉铃虫为害造成的花蕾脱落和自然脱落,增加有效铃数和产量,但增加量没有达到显著水平。     

陆地棉主要纤维品质性状的基因效应估测

本文采用世代平均数遗传分析方法,沿用了加性-显性、加性-显性-上位性和环境(二种)×基因型三种模型,对陆地棉主要纤维品质性状中的长度、细度、强度和断裂长度的基因效应、年份效应以及年份×基因型互作进行了估测。经过三年的实验,选用三个杂交组合,每一组合含有P_1、p_2、F_1、F_2、B_1和B_2六个群体的资料。结果表明,四个纤维品质性状的遗传受加性、显性、上位性作用的共同控制,但在不同年份或不同的组合里,显性作用和上位性作用的变化较大;年份效应对品质性状的遗传也有较大影响,其影响方式主要以年份×基因型互作的形式表现。     

大丽轮枝菌毒素的脂肪组分对棉花致萎活性研究

用脂肪酶(37℃,6小时)水解不同致病力类型的5个大丽轮枝菌(Verticillium dahliaeKleb.)毒素中的脂肪组分。试验结果表明经过水解后的5个菌株的毒素都不影响对棉花的致萎活性,说明毒素中的脂肪组分在对棉花的致萎作用中不占重要地位。     

棉花751与多父本杂交受精细胞学研究及性状分析

本文报导了以棉花７５１为母本与鸡脚叶棉、乌干达棉、红叶棉、汉寿大桃、草棉等５个父本的混合花粉进行杂交。授粉后,观察了７５１大小孢子和雌雄配子体的发生、发育及其受精过程。切片观察表明在大小孢子的发生、发育与花蕾大小成正相关。大小孢子的发生在减数分裂前是不同步的。小孢子的发生早于大孢子发生１￣２个时期。减数分裂后它们的发育逐渐趋向同步。开花时达到同步成熟。用多父本的混合花粉授粉,其受精过程仍为单精入卵