利用近等基因系研究3个抗水稻纹枯病QTL的聚合效应

利用特青/Lemont组合的回交群体,证实了特青第7染色体上存在抗纹枯病QTL qSB7Tq。以Lemont为轮回亲本,通过分子标记辅助连续回交结合性状鉴定,构建了qSB7Tq与另外两个抗水稻纹枯病QTL qSB9Tq（位于特青第9染色体）和qSB11Le（位于Lemont第11染色体）的一套近等基因系,对各抗性QTL的单个效应及其聚合效应进行了研究。3个抗性QTL单独存在或在聚合状态下均能显著提高水稻品种对纹枯病的抗性水平。但是,不同抗性QTL之间可能普遍存在一定的负向互作关系。讨论了一致的遗传背景对QTL研究的重要性,以及不同QTL的聚合效应及互作关系对育种实践的意义。     

脂肪酸合成酶基因(FASN)的研究进展

在哺乳动物中,脂肪酸合成酶在脂肪酸合成中起着至关重要的作用。它含有7个活性位点,在还原型辅酶Ⅱ的存在下,FASN负责乙酰辅酶A(acetyl-CoA)和丙二酰辅酶A(malonyl-CoA)从头合成一种长链软脂酸(棕榈酸酯)的所有催化步骤。脂肪酸合成酶是脂肪合成的关键酶,并且在腹脂肪组织重变异及相关性状变异中起着重要作用。综述了FASN及其基因在生命活动中的地位、作用、定位、结构及FASN基因的遗传变异与生产性状关系的研究进展。     

Foliar morphological variation in the white oak Quercus rugosa Née (Fagaceae) along a latitudinal gradient in Mexico: Potential implications for management and conservation

Quercus rugosa Nee (section Quercus) has a distribution from the southern United States to Honduras. This study characterized leaf variation across the whole distribution of the species in Mexico. Ten foliar morphometric characters were scored in each of 241 individuals from 25 localities. A principal component analysis resolved four principal components (PCs) that explained 76.4% of the total variation. A nested analysis of variance revealed significant differences among populations (29.2% average contribution to total variance for the four PCs) and among-trees within populations (39.2%), while 31.6% was due to intra-individual variation. For the first PC (related to leaf size), 52.1% resulted from among population differences. This variation was negatively correlated with latitude (r = −0.86; P < 0.0001), indicating a steep clinal reduction in leaf size from south to north. Mean annual precipitation and an annual aridity index also significantly decreased and increased with latitude, respectively. It is suggested that the morphological cline is the result of plastic and/or adaptive responses to environmental conditions, and indicative of further ecophysiological latitudinal differences among Q. rugosa populations. Additionally, we estimated the magnitude of the least significant difference among populations for the first PC and translated it into a delineation of six latitudinal zones (each with a width of 2°30′), to be considered as preliminary zones for the movement of Q. rugosa seeds with management and conservation purposes, including management in response to global warming.     

Morphological and biological investigation of two pioneer Ips bark beetles in natural spruce forests in Qinghai Province, northwest China

Bark beetle species in natural stands of spruce, Picea crassifolia （Kom.） were investigated in Maixiu Forest Park, Qinghai Province, northwest China, during 2005 and 2007. Two pioneer Ips species, Ips nitidus Eggers and Ips shangrila Cognato and Sun were found. I. nitidus occurs naturally in northwest China. I. shangrila is a new species in the world. In the past, it was confused with I. mannsfeldi Wachtl in China. The damage of these two Ips species has been very severe in Maixiu and the morphological and bio-logical characteristics were studied. I. nitidus starts to fly in early May and prefers the mid to lower part of the host tree to colonize as its habitat. I. shangrila always infests from the top of the trunk, especially in branches larger than 3 cm in diameter in the crowns and sometimes even colonizes entire young trees. The two Ips species are the most destructive secondary bark beetles on P. crassifolia and always cause mortality of trees by their cooperation.     

Effects of nutrition spatial heterogeneity on root traits and carbon usage by roots of Cercis chinensis seedlings in split root rooms

In natural ecosystems, nutrition available for plants shows great spatial heterogeneity. Much is known about plant root responses to the spatial heterogeneity of nutrition, but little is known about carbon usage in roots in nutrition-deficient patches and its effect on root longevity. In this study, split-room boxes were used for culture of Cercis chinensis seedlings, and the small rooms were supplied with different nutrition levels. The number of the first-order roots in the rooms with nutrition supply was significantly higher than that in the rooms with deficient nutrition. Specific root length (SRL) of the first-order roots in the rooms with deficient nutrition reached its peak at day 64 after nutrition treatment. There was no significant SRL differences between the two order roots during the experiment. Biomass of the first-order roots in the rooms without nutrition supply was significantly less than that of the first-order roots in the rooms with nutrition supply from day 64 to 96. The total biomass of the lateral roots in the rooms without nu-trition supply decreased from day 64 to 96. The activities of the enzymes in roots in the rooms without nutrition supply increased and the activities of alkaline invertases in roots in the two sides of split box did not change significantly. The activities of the enzymes in roots in the rooms without nutrition supply increased gradually. These results suggest that nutrition spatial heterogeneity induced the changes in root traits and plants actively controlled carbon usage in roots in nutrition-deficient patches by regulating the activities of invertases and sucrose synthases, resulting in the reduction in carbon usage in the roots in nutrition-deficient patches.     

中国鲎幼鲎形态性状与体重的通径分析及异速生长研究

为了探究不同龄期中国鲎幼鲎生长特性,实验测定了2～4龄幼鲎头胸部长(X₁)、头胸部宽(X₂)、腹部长(X₃)、腹部宽(X₄)、剑尾长(X₅)、全长(X₆)和体重(Y)等参数,运用相关分析和通径分析方法,探讨形态性状对体重的作用效果。结果显示,2～4龄幼鲎体重相关系数最高的形态性状均为头胸部宽(X₂);通径分析发现,头胸部宽(X₂)对2龄和3龄幼鲎体重直接影响最大,腹部宽(X₄)对4龄幼鲎体重直接影响最大;各形态性状对体重决定程度分析与通径分析变化趋势一致。对2～4龄幼鲎头胸部宽和体重进行对数处理,获得异速生长方程回归系数(b)为2.746,表明此阶段幼鲎体重增长率大于头胸部宽增长率,处于正生长期。实验表明,不同龄期阶段中国鲎苗种筛选所依据的形态性状有所差异,中国鲎幼鲎阶段种质评价应考虑其异速生长规律,同时也为探究鲎的生长与性状、结构与生理之间的关系奠定基础。     

不同选育品系中华绒螯蟹形态特征的比较分析

以不同选育品系(“江海21”“长江1号”“诺亚1号”和“申江1号”)中华绒螯蟹(Eriocheir sinensis)为试验对象,通过单因素方差分析、逐步判别分析和主成分分析等方法对4个品系中华绒螯蟹的形态特征进行比较分析。结果显示：(1)单因素方差分析中,各品系雌、雄个体的32项形态特征指标均不存在显著性差异(P>0.05);(2)逐步判别分析中,各品系雌、雄个体的判别准确率普遍较低,仅为40%～70%;(3)主成分散点图显示,各品系个体之间频繁交叉出现,主成分分析难以区别各品系的雌、雄成蟹个体。综合分析结果表明,中华绒螯蟹各品系之间的形态特征差异较小,难以将形态学特征作为鉴别各选育品系的特定指标。     

小麦抗旱机制研究进展

小麦是我国北方的主要粮食作物,土壤干旱严重影响了小麦的生长发育.从小麦形态结构包括根系构型、结构及叶片形态,生理机制包括光合作用、渗透调节、酶及蛋白含量,分子生物学研究等方面较系统地综述了小麦抗旱机制的研究进展;对今后的研究方向进行了展望.     

不同灌水量对温室甜瓜生长和生理特性的影响

以"一品天下208" 甜瓜为试验品种,在日光温室内进行了灌溉试验,采用20蒸发皿的日水面蒸发量为灌溉水量控制指标,设置了不同蒸发量系数(K_p=0.45;0.6;0.75;0.9)的供水处理,探求不同灌溉水量对温室甜瓜生理指标、形态指标和光合生理指标的影响.结果表明:温室内外温度的变化趋势基本相似,温室内的温度能够满足甜瓜的正常生长.不同处理的灌溉水量比值始终为T1:T2:T3:T4=0.45:0.6:0.75:0.9;从甜瓜的株高、茎粗、总生物量、根冠比等指标综合分析,采用T2(K_p=0.6)处理均优于其它水分处理,且根冠比也处于一个较高的水平;叶绿素a、叶绿素b、叶绿素总量均以T2处理最高;各处理的细胞液浓度的变化呈单峰曲线,不同处理的叶片细胞液浓度表现为T1>T2>T3>T4处理.结果表明:采用T2处理的灌溉模式有利于甜瓜在获得较高产量的前提下降低灌溉用水量.     

高品质陆地棉农艺性状与皮棉产量的关系分析

1材料与方法 1．1材料 供试24份高品质陆地棉品系分别为A001、A016、A018、A106、A107、A111、A112、A113、A201B、A203B、A210、A301、A402B、A405B、A407、A408、A413、A705,A708、A709、A9—1、P2、P4。