分子标记在优质蛋白玉米（QPM）育种中的应用

 与opaque-2（o2）基因紧密连锁的分子标记，可以有效地用于优质蛋白玉米育种。本研究利用SSR标记，检测了QPM群体中群13、中群14内o2基因的频率分布，发现中群13、中群14在o2基因位点基因频率发生了改变。检测了从QPM群体中选育的高代系中o2基因的频率，发现在CA、CD、CB和R高代系中o2o2基因型频率分别为91.7%、80.0% 、0.0和100%。表明用常规方法选育QPM自交系，不能有效地保证o2基因纯合。为了拓宽QPM种质基础，利用分子标记追踪普通玉米与QPM自交系回交后代的o2基因，将普通自交系转育为QPM，结果表明非常有效。     

火炬松木材纤丝角和管胞长度的变异及其相关分析

在３处立地上各选５株１７．５ａ生火炬松木材，分别测定其管胞长度、纤丝角，并对２性状间的相关性进行了分析。结果：火炬松管胞长度由髓心向外递增，纤丝角由髓心向外递减，２性状在径向上呈显著的线性负相关；３处立地上林分内以及不同立地上林分间２性状均不呈显著的负相关，这说明株间木材管胞长度不能预测纤丝角。林木育种在评定优良种源、无性系，以及营林培育评价营林措施对木材材质的影响时，只能实测纤丝角。     

Effects of spinning processes on HVI fiber characteristics and spun yarn properties

The effects of opening, carding, and repeated drawings on single fiber and bundle cotton characteristics were studied by employing Mantis®, AFIS® and HVI Testers. Some of the significant changes in single fiber properties were found to be due to process parameters as well as the changes in the fiber crimps, parallelness of fibers within HVI beards, and the actual changes in the tensile properties of the fibers. The study showed that the HVI test data taken just prior to spinning had the highest correlation with the yarn tensile properties. Based on the study results, we point out the potential of HVI for future quality and process control in spinning by recommending a set of expanded HVI output that is more scientific and comprehensive for the future control needs.     

全射流喷头重要结构参数对水力性能的影响

喷头是喷灌系统中的关键部件，其性能好坏直接影响喷灌的效果。该文提出了一种国内原创的全射流喷头，分析了全射流喷头重要结构参数对其工作性能的影响，通过改变样机尺寸的试验验证理论分析的正确性。结果表明，试验结果与理论分析相符合，影响喷头工作状态的主要结构参数包括信号嘴插拔深度、间隙C、导管长度、位差大小和作用区长短等，最后提出了样机的最佳结构参数。     

Crop residue and Collembola interact to determine the growth of mycorrhizal pea plants

The effects of collembolan grazing on arbuscular mycorrhizal (AM) fungi and plant growth were studied in a controlled experiment utilizing a mix of AM fungi and the dominant collembolan species (Isotoma sp.) indigenous to the experimental soil. Collembolan (+/– Col) effects were examined in the presence and absence of crop residue (+/– Litter) incorporated into the experimental soil. Significant interactions between collembolans and crop residue occurred for mycorrhizal colonization of roots and plant growth. In the absence of crop residue, collembolans reduced root length colonized by AM fungi, total plant dry mass and seed pod yield. However, in the presence of crop residue, collembolans had no effect on root colonization by AM fungi, and increased total plant mass and pod yield. Crop residue increased root colonization by AM fungi, numbers of bacteria and saprophytic fungi (colony forming units), small- (<5 m) and large- (>5 m) diameter hyphal lengths in soil, and the final population of collembolans in soil. Collembolans reduced both small- and large-diameter hyphae in soil and the number of saprophytic fungi (colony forming units, p =0.052). Feeding preference experiments conducted in vitro showed that Isotoma sp. preferred to graze on mycorrhizal roots over nonmycorrhizal roots when given no other food choice. However, when crop residue was added as a food choice, Isotoma sp. showed a clear feeding preference for crop residue. We conclude that collembolan grazing on mycorrhizae can be detrimental to plant growth when other fungal food sources are limited, but grazing on mycorrhizal fungi does not occur when ample organic matter and associated saprophytic fungi are present in soils.     

滴施缩节胺与氮肥对棉花生长发育及产量的影响

为探明缩节胺与氮肥对棉花农艺性状的互作效应,试验采用双因素随机区组设计,设置150 (N1)、300 (N2)、450 kg hm–2 (N3) 3个施氮(纯N)水平, 525 (D1)、1050 (D2)、2100 g hm–2 (D3) 3个缩节胺水平,交互共9个处理。研究滴施不同剂量氮肥与缩节胺对棉花农艺性状、棉铃时空分布、干物质积累及分配、产量及纤维品质的影响。结果表明,缩节胺与氮肥互作效应对棉花农艺性状影响显著,在低氮状态下缩节胺对棉花生长的延缓作用减弱甚至消失。N1处理下, D3处理相比D1处理棉株的株高、果枝始节高、第4果枝长、第7果枝长分别增加12.07、1.54、1.28和1.20cm。在正常或高氮状态下缩节胺对棉花生长产生一定的延缓作用,其控制效果并不随缩节胺剂量增加而增强,N3处理下,D3处理相比D1处理棉株的株高、第1果枝长、第2果节间平均长度分别降低1.05、1.68和1.52cm。棉株的株高、茎粗与果枝数随施氮量增加而增加, N3处理相比N1处理分别增加3.30 cm、0.75 mm与0.29台;其果枝长与果节间长在不同施氮量间无明显差异。D2处理相比D1与...     

红河干旱河谷地区植物根系与砾石对土壤优先路径形成的影响

为探究红河干旱河谷林草地植物根系与砾石特征对土壤优先路径形成的影响,基于染色示踪法在确定研究区样地土壤优先路径的位置及数量的基础上,结合染色区的植物根系与砾石体积含量特征,定量分析二者与优先路径特征的关系。结果表明:(1)林地优先路径发育水平明显优于荒草地; 不同染色影响半径范围下的优先路径连通性也有所不同,其中荒草地中优先路径连通性从大到小为1～2.5 mm,≤1 mm,2.5～5 mm,5～10 mm,>10 mm; 林地为1～2.5 mm,2.5～5 mm,≤1 mm,5～10 mm,>10 mm; 优先路径数量与土层深度和同一土层内染色半径均呈负相关关系,此外,在同一土层内,优先路径的数量与染色半径也呈负相关关系。(2)林地中染色区的砾石总体积含量与土层深度呈负相关,而荒草地中在20—30 cm土层中增多,其余径级下的则随土层深度增加而减少;(3)两种样地中的根长密度与根重密度都随土层的深度增加和根径增大而单调递减,林地中不同径级下的根长密度都明显高于荒草地;(4)林地中优先路径数量的主要影响因子是根径范围在≤1 mm的根重密度和径级为5～10 mm的砾石体积含量; 而荒草地样地中的主要影响因子为根径在≤1 mm和1～3 mm范围下的根重密度、径级在2～5 mm间的砾石体积含量、根径在1～3 mm范围下的根长密度。因此,样地中砾石分布存在明显的空间异质性,细根更易促进优先路径的形成,二者共同影响着优先路径的形成。     

多花黄精实生育苗及幼苗生物质积累规律分析

多花黄精苗播种育苗难度大,实生苗生物质积累规律尚待研究。笔者对其种子的发芽率、发芽势以及1~2年生苗进行跟踪观测。结果表明,多花黄精种子发芽率、发芽势均达80%以上,种子生活力强。该种子萌发周期长,部分植株于次年春季长叶。1年生苗属于先长根茎根系、再长叶片的生长发育类型;2年生苗叶片增长明显,其次是根系,再次是块茎,且2年生苗大多为单叶,仅有极少数为双叶或三叶。从第2年开始,地上叶片生长速度加快,但地下部分所占比例仍然较大,为全株的69%。表明随着叶片光合作用增强,黄精地下块茎生长优势越发明显。     

红麻韧皮部束纤维层的分离及纤维长度分布

采用亚氯酸钠一冰醋酸和草酸铵处理，将不同部位的红麻韧皮部束纤维进行分层，并测定各束纤维层的纤维细胞长度，探讨红麻韧皮部纤维细胞长度的分布规律。