广州下半年负离子分布的时空特征

为研究广州市下半年空气负离子分布的时空特征,利用空气离子测量仪,在广州市选择典型的采集地,分析了空气负离子的月际变化、功能区类型、取样时段、典型环境对空气负离子浓度的影响。结果表明：（1）所测定的几种功能区空气负离子浓度大小顺序为：华南农业大学跃进南宿舍区〉广州市白云山〉华南农业大学树木园〉广州市天河区五山路;（2）月际变化：9月到11月负离子没有明显的变化,而12月负离子含量明显的减少;（3）负离子浓度最大值出现在晚上19：00～20：00,一天之内的负离子浓度变化呈早、晚较高,中午低的规律;（4）对广州几种典型环境进行测定,负离子浓度大小顺序为：近水区（林中（游憩区（道路;（5）广州市下半年负离子浓度最大值高达58 000个/cm^3,而最小值仅为1 000个/cm^3。     

Genetic variability of heat tolerance, and its effect on yield and fibre quality traits in upland cotton (Gossypium hirsutum L.)

Global temperature is rising because of increasing concentrations of CO₂ and other greenhouse gases (e.g. methane, nitrous oxide, etc.) in the atmosphere because of the excessive use of fossil fuels. High temperature causes heat stress which reduces crop productivity. The development of heat-tolerant varieties is feasible and will help mitigate the effects of climate change. Fifty-one cotton accessions were screened in heat-stressed and non-stressed conditions in the glasshouse and field. Relative cell injury percentage (RCI %), a measure of cell membrane thermostability (CMT), was used to assess heat tolerance. Heat-tolerant accessions had more stable yield and yielded more seed cotton with better quality fibre than the heat-intolerant accessions across four environments. The responses of the 51 accessions to all four environments for the measured traits were strongly associated. RCI % of the accessions and hybrids was strongly and negatively associated with yield and fibre traits. CMT was concluded to be a useful technique for identification of heat-tolerant cotton.     

CIMMYT牧草DNA导入普通玉米后植物学形态变异研究

本研究以CIMMYT牧草和4个普通玉米自交系为遗传交配材料,比较研究了CIMMYT牧草和4个杂交（回交）后代的植物学形态特征及其与普通玉米的差异。结果表明,CIMMYT牧草能将其生长繁茂、分蘖力强、生物产量高的特性遗传给杂交后代,并有较强的世代传递能力;该牧草幼苗、植株及其生长习性、花器官、种子特征等与普通玉米差异明显,其与普通玉米的杂交后代基本保持了它的生长发育特性,但花器官和种子特征更偏向于普通玉米;回交后代除保持了一定的分蘖特性、明显的多穗和返祖现象外,其余特征特性与普通玉米基本没有区别。     

野生玫瑰抗旱性地理变异的初步研究

以吉林珲春,山东牟平,山东荣成3个地理种源的野生玫瑰为材料进行盆栽试验,研究了干旱胁迫下玫瑰的生理生化变化与抗旱性强弱。结果表明,干旱胁迫条件下, 3个种源野生玫瑰的5个抗旱生理生化指标的变化趋势基本一致,但各指标的变化程度因种源不同而异。通过“坐标综合评定方法”对5个生理生化指标进行综合评定,得到3个种源野生玫瑰的抗旱性强弱等级依次为吉林珲春,山东牟平,山东荣成。     

大豆遗传群体选择与品质QTL的获得

本文以高油品种哈交97-5404-1为母本,以哈交99-5448-4为父本,建立重组自交系群体.应用SSR技术,对不同世代F2∶3,F2∶6、F2∶9遗传群体中的油份QTL定位进行了分析,不同世代大豆分离遗传群体中油份含量均接近于正态分布,油份含量性状表达偏向于母本哈交97-5404-1,F2∶3代获得了对油份贡献率较高的QTL,F2∶9代则获多个与油份相关的QTL,大豆F2∶3和F2∶9代的遗传群体适宜用做品质性状的QTL定位,不同世代定位的油份QTL,均与SSR位点Satt193有关,通过对来自全国不同品种的SSR进行了分析和方差分析证实,Satt193在第一等位变异下(即DNA片段长度为270 bp)做为油份的筛选标记具有实用性,而在第三等位变异下(即DNA片段长度为220 bp)做为蛋白质材料的筛选标记具有应用性.     

30个中国甘薯主栽品种的RAPD指纹图谱构建及遗传变异分析

研究以中国30个甘薯主栽品种为材料,对甘薯RAPD指纹图谱的构建进行了探讨。从102个RAPD引物中筛选出26个多态性丰富的引物用于PCR扩增,共扩增出255条多态性条带,平均每个引物扩增的多态性带数为9.8条。其中S32和S39多态性最高,仅用其中1个引物即能将这30个甘薯品种完全区分开,且由此构建的指纹图谱出现的概率很小,分别为4.77×10^-7（1/221）和1.91×10^-6（1/219）。结果进一步表明,这30个甘薯品种的遗传距离变异幅度较大,为0.0390～0.4306,平均遗传距离为0.3086。RAPD聚类分析表明,地域分布相近的甘薯品种和具有同一亲本的甘薯品种聚在一起,与这些甘薯品种的系谱图一致。     

粉单竹纸浆材材性的地理变异及产地选择

以广东、广西和海南3个省(区)8个产地的粉单竹群体3年生竹秆为研究材料,对其纤维形态、化学成分等纸浆材性指标进行测定,采用方差分析和相关分析方法对上述竹材性状进行遗传变异分析,以揭示粉单竹材性的地理遗传变异规律.结果表明: (1)粉单竹的纤维长度、纤维素和1%NaOH抽出物含鼍在产地间存在极显著或显著差异.纤维长度及纤维长宽比呈现纬度上从南到北(海拔上从低到高)逐渐减小的地理变异模式;(2)纤维素和纤维长度的遗传力分别为O.71和O.84;1%NaOH抽出物遗传力为0.54;木素和纤维长宽比的遗传力分别为O.38和O.13; (3)性状间相关分析表明,竹材产量与1%NaOH抽出物和苯醇抽出物呈显著负相关,与纤维素含量呈显著IE相关;纤维形态与生长、产量指标关系密切;最后,通过主成分分析进行联合选择,初步选出材性质量好、生长旺盛、竹材产量高的广东怀集、广东信宜和广西桂林3个优良纸浆材产地.     

Dynamic emulation of the effect from a single tree to lower solar radiation distribution

By modeling the condition of light climate, we studied the negative effect of shadows in a shelterbelt forest. Based on the calculation of the apparent trajectory of solar motion according to an ellipsoid crown projection model and a Monsi light transmission model, radiation values of 36 experimental sites were measured using a light quantum meter. Estimates of daily solar radiation distribution from measured values were obtained. We built a crown projection model and simulated the conditions of a light climate in the forest. The trajectory of the shadow motion is shaped like a butterfly arc. The situation of the outside is affected by tree height (H) and that of the inner arc by height below the branches. In an area of 1.0 × H (toward the east and west of the tree) and 0.6 × H (toward the north), transmittance was below 90%, which means that the effect of shadow hazards occurs in this area. As well, the effect was strong at the bottom of the tree. The area of shadow hazards in the east and west of the tree was large and small in the south. The projection area of the shelterbelt forest was largest along an east and west direction. A certain distance between crops and the shelterbelt should be maintained when the shelterbelt is in a north-south direction. Therefore, the effect of shadow hazard will decrease north of the tropic of cancer. Cutting out the lower branches from the trees of the existing shelterbelt in a suitable and timely manner can reduce the area of the shadows. __________ Translated from Journal of Northwest A&F University, 2008, 36(6): 113–118 [译自: 西北农林科技大学学报]     

Genetic stability at nuclear and plastid DNA level in regenerated plants of <Emphasis Type="Italic">Solanum</Emphasis> species and hybrids

In this work we detected the extent of variability at nuclear and cytoplasmic DNA level of regenerated plants belonging to Solanum genotypes with a different genetic background and somatic chromosome number. As for the nuclear characterization, a total of 66 (18.5%) polymorphic bands were scored using 13 ISSR primers on 45 randomly selected regenerants. Our results show that the regenerants obtained from clone cmm 1T and, at lower level, those from cph 1C are unstable under in vitro conditions or rather more prone to in vitro-induced stress leading to somaclonal variation than the other genotypes used. Two types of changes were observed: disappearance of parental ISSR fragments, termed “loss”; appearance of novel ISSR fragments, termed “gain”. The most frequent event occurring in the regenerants was the loss of fragments (41 bands). Regenerated plants were analyzed with seven plastid universal primers to determine the cytoplasmic composition at chloroplast level. All cpDNA primer pairs tested produced amplicons of the same size in all genotypes analyzed and no polymorphic fragments were observed with any universal primers used. Our results show that under in vitro culture conditions genotype affects the integrity of the genome. In addition, the absence of polymorphism at plastid level confirms the greater genetic stability of cytoplasmic DNA.     

Inter- and intraspecific sequence variations of the chloroplast genome in wild and cultivated Raphanus

To assess the differentiation of the chloroplast genome in wild and cultivated species of Raphanus , nucleotide sequence polymorphisms were investigated for approximately 2 kbp ranging from trnL (UAA) to psbG in R. raphanistrum and R. sativus . Eighteen plants of wild species, 10 Japanese wild radish plants ( R. sativus ), and 31 cultivated plants were used for sequence analysis. Intraspecific variations of the chloroplast genome were present both in wild and cultivated Raphanus . All three genes investigated ( trnL , trnF and ndhJ ) contained nucleotide substitutions within the genus. Whereas, larger numbers of mutations were observed in the intergenic regions. Using the detected variations, the 59 radish plants were classified into 11 haplotypes, seven of which were unique to wild species. Among the haplotypes, one type corresponded completely with the Ogura male sterile cytoplasm. All the cultivated radishes belonged to one of four types, of which three were also observed in Japanese wild radish. The haplotypes were classified into four groups by cluster analysis, and the distribution in the dendrogram confirmed that cultivated radish has multiple origins. On the other hand, the seven haplotypes uniquely observed in R. raphanistrum were considered as useful materials to provide genetic diversity of cytoplasm for breeding of cultivated radishes.