豫综5号玉米群体产量性状轮回选择改良效果分析

以半姊妹和相互半姊妹轮回选择改良的豫综5号5个轮次群体为材料,通过2点产量比较试验,对豫综5号群体产量及穗部性状的改良效果进行了比较研究.结果表明,随着改良轮次的增加,豫综5号群体的单株产量逐轮提高,平均每轮提高6.36%,其中,半姊妹轮回选择改良的3轮群体平均每轮提高6.30%,相互半姊妹轮回选择的改良群体提高5.51%,群体产量的变异系数从15.4%下降到12.8%,基本符合选择预期效果,群体内仍有较丰富的变异,说明2种选择方法对群体单株产量的改良是有效的.对改良群体穗部性状的比较发现,穗长和行粒数分别提高5.27%和9.96%.说明穗长和行粒数的改良效果明显,它们的提高是群体单株产量提高的主要因素.本研究还对相互轮回选择的方法和豫综5号群体改良利用等问题进行了探讨.     

玉米光周期敏感相关性状发育动态QTL定位

玉米是短日照作物,大多数热带种质对光周期非常敏感。光周期敏感性限制了温、热地区间的种质交流。研究玉米光周期敏感性的分子机理,有利于玉米种质的扩增、改良、创新,提高玉米品种对不同光周期变化的适应性。本研究以对光周期钝感的温带自交系黄早四和对光周期敏感的热带自交系CML288为亲本配置的组合衍生的一套207个重组自交系为材料,在长日照环境条件下对不同发育时期的叶片数、株(苗)高变化进行QTL分析。结果表明,双亲间的最终可见叶片数和株高差异很大;发育初期CML288的叶片数和苗高都低于黄早四,而发育后期CML288的叶片数和株高都明显高于黄早四;测定各时期F₇重组自交系间也存在显著差异。利用包含237个SSR标记、图谱总长度1 753.6 cM、平均图距7.40 cM的遗传连锁图谱,采用复合区间作图法,分别检测到控制叶片数和株(苗)高发育的QTL 11个和20个。但是,没有一个条件QTL 能在测定的几个时期都有效应。在长日照条件下,控制叶片数与株(苗)高的非条件与条件QTL主要集中在第1、9和10染色体上,特别是在第10染色体的标记umc1873附近均检测到了影响这两个性状的QTL,且在不同的发育时期单个条件和非条件QTL所解释的表型变异分别为4.34%~25.74%和10.02%~22.57%,表明这一区域可能包含光周期敏感性关键基因。     

Long-lived volcanism on the lunar farside revealed by SELENE Terrain Camera

We determined model ages of mare deposits on the farside of the Moon on the basis of the crater frequency distributions in 10-meter-resolution images obtained by the Terrain Camera on SELENE (Selenological and Engineering Explorer) (Kaguya). Most mare volcanism that formed mare deposits on the lunar farside ceased at approximately 3.0 billion years ago, suggesting that mare volcanism on the Moon was markedly reduced globally during this period. However, several mare deposits at various locations on the lunar farside also show a much younger age, clustering at approximately 2.5 billion years ago. These young ages indicate that mare volcanism on the lunar farside lasted longer than was previously considered and may have occurred episodically.     

温带和热带玉米重组自交系群体的株高QTL分析

以光周期钝感自交系黄早4和光周期敏感自交系CML 288为亲本杂交所衍生的F10代重组自交系为材料,构建了覆盖玉米10条染色体的含有237个SSR标记的遗传连锁图谱;采用复合区间作图法对3种不同长短日照环境下的株高进行QTL定位,在4个地区3个不同的光周期环境下共检测到11个与株高有关的QTL.在第1条染色体1.10区域的1个QTL在各个日照条件下都能够稳定表达;位于第10染色体10.04区域的1个主效QTL PH 10在长日照务件下特异表达,且具有较大的贡献率、效应值和LOD值,推断在该区段上存在控制玉米光周期敏感性的QTL.     

Developmental changes in testicular luteinising hormone receptors and androgens in the dog

The changes with age in the levels of testicular luteinising hormone (LH) receptors in dogs, were correlated with plasma androgen concentrations and the effects of stimulation with human chorionic gonadotrophin (hCG). The presence of high-affinity binding sites for lh was demonstrated in the testes of all the animals studied, and the apparent affinity of the LH receptors did not change significantly with age. The total number of LH receptor sites per testis increased continuously with age and the growth of the testis. The major rise in the number of LH receptors occurred between six and 10 months of age, and coincided with the phase of rapid testicular growth. The concentrations of androstenedione, testosterone and 5α-dihydrotestosterone in plasma increased gradually until six months of age, and then increased rapidly with the increase in the number of testicular LH receptors. An increase in the concentrations of androgens in plasma was observed in response to stimulation with hCG after the number of testicular LH receptors began to increase progressively. The increase in the sensitivity of the dogs' gonads to LH could be responsible for the marked increase in the secretion of androgens which occurs during puberty in the male dog.     

免耕覆盖对春小麦灌浆期干物质积累特性及最终产量的影响

以常规耕作处理作对照,研究了免耕覆盖下春小麦灌浆期间干物质积累分配特性和产量变化,结果表明,高、低秸秆覆盖量下春小麦灌浆期间干物质积累量比常规耕作分别高16.1%、9.8%,免耕秸秆覆盖为春小麦籽粒和产量形成提供了更充足的物质来源;与常规耕作比,免耕覆盖处理的春小麦在花后21-28 d时干物质积累量有个快速增加阶段;在干物质的运转分配中,免耕覆盖对春小麦灌浆期积累的干物质在各个器官间的分配比例影响较小。相对于常规耕作而言,免耕秸秆覆盖处理提高了春小麦产量,其产量的增加主要依赖于花前光合产物的积累,对花后光合产物调用较少。低覆盖量下春小麦较常规耕作增产11.68%,高量覆盖较常规增产18.52%。     

玉米类LFY基因的克隆及其在不同光周期条件下的表达

采用每天9 h和15 h两种光照条件对热带玉米自交系CML288和温带玉米自交系黄早四进行处理。以玉米茎尖为材料，采用RT-PCR方法，分离到1个1 265 bp的全长cDNA克隆，序列比较表明其为拟南芥LFY基因的同源基因，命名为类LFY（基因登录号为DQ343237）。类LFY与同源基因zfl2、RFL、LFY和FLO的同源性依次为93%、84%、57%和57%。它的DNA序列和推论的蛋白质序列与zfl1同源性最高，其编码的蛋白质与zfl1相比在第28、29和160位分别少1个丙氨酸、脯氨酸和苏氨酸，在188位置多1个甲硫氨酸。该基因在2个供试自交系茎尖中长日照条件下不同生长时期持续表达，短日照条件下生长早期和后期不表达，其功能有待进一步研究。     

Growth Response and Fatty Acid Composition of Juvenile Procambarus clarkii Fed Different Sources of Dietary Lipid

An experiment was conducted to evaluate the effects of feeding various sources of dietary lipidon weight gain, feed conversion, survival and fatty acid composition of juvenile red swamp crawfish, Procam-barus clarkii. Six semi-purified diets containing vitamin-free casein, defatted soybean meal, 0.5% cholinechloride, 0.5 % glycine and 0.5 % cholesterol were supplemented with 6.0 % of either anchovy oil, linseed oil,soybean oil, rapeseed oil, safflower oil or pork lard. Each diet was fed to crawfish (3.07±0.21 g averageweight) in three replicate aquaria for 60 days. Survival rate, weight gain and feed conversion were best forcrawfish fed the diet containing anchovy oil. Crawfish fed the linseed oil diet had the second highest weightgain, followed by crawfish on soybean oil, repaseed oil, safflower oil and pork lard diets, respectively. Feedconversion values were a reflection of weight gain. Results showed that both n-6 and n-3 fatty acids are dietaryessential for juvenile Procambarus clarkii, although n-3 fatty acids promoted faster growth than n-6. Howev-er, highly unsaturated fatty acids (HUFA) (20 : 5n-3 and 22 : 6n-3) had better growth-promoting effect than18 : 3n-3, due probably to the limited ability of crawfish to bioconvert fatty acids to polyenoic forms of longerchain length. The fatty acid composition of the crawfish generally reflected that of the dietary lipids, especial-ly for the diets containing unsaturated fatty acids.     

3维图像处理系统在稻米品质检测中的应用研究

利用微切片3维图像处理系统对稻米的品质特性进行了探索性的研究。结果表明，借助于3维可视化技术，可以对稻谷的外观品质、营养品质及蒸煮品质等进行更为直观且客观的观察与测定。尤其是在营养成分分布密度的评价、心白米内部组织的分析、蒸煮过程中组织结构变化的观测等方面，取得了传统研究方法难以获得的结果。利用该系统对垩白度的定量化测定，为食品的定量形态学研究开辟了一条新的研究途径。     

Spatial distribution of Raffaelea quercivora hyphae in transverse sections of seedlings of two Japanese oak species

To compare the distributions of Raffaelea quercivora hyphae within seedlings of a susceptible species, Quercus crispula, and a resistant species, Q. glauca, we examined water conductance at transverse sections. Raffaelea quercivora was inoculated into the stems of seedlings in July (summer) and October (autumn) and observed by light and fluorescence microscopy at 1 and 2 weeks after inoculation. The hyphal distribution patterns expressed as the I_δ index differed between the species at each occasion. The hyphal growth was wider in Q. crispula than in Q. glauca in July inoculation, but did not differ in October inoculation. Non‐conductive sapwood in Q. crispula in transverse section was wider than that in Q. glauca at each occasion. The differences of hyphal growth and hyphal distribution patterns between species as little as 1 week after inoculation reflect differences in host susceptibility to the fungus.