不同棉铃发育时期遮荫对棉纤维品质性状的影响

以中棉所41和鲁棉研18两品种为试材，设计3个遮荫时期（处理Ⅰ：棉铃发育0～20 d；处理Ⅱ：棉铃发育21～40 d；处理Ⅲ：棉铃发育41 d到吐絮），研究了遮荫对棉花纤维品质性状影响的规律。结果表明，遮荫使纤维长度变短，纤维伸长期增长，CK在25 d纤维达最大长度，处理Ⅰ、处理Ⅱ分别在35 d、30 d才达到最大长度，而处理Ⅲ对纤维伸长期没有影响；各时期遮荫都降低纤维断裂比强度和纤维成熟度，但使纤维细度增加，其中处理Ⅱ对纤维比强度、纤维成熟度和纤维细度的影响最大，与CK差异均达极显著水平；处理Ⅰ和处理Ⅲ影响较小。各时期遮荫对两品种纤维品质性状的影响趋势一致。     

水稻籽粒直链淀粉及蛋白质含量对孕穗期弱光胁迫的响应

以2个不同直链淀粉含量的水稻品种为材料，研究了孕穗期遮光（遮光率50％）对水稻籽粒直链淀粉及蛋白质含量的影响。结果表明，遮光与对照的籽粒直链淀粉的积累过程均可以用二次曲线回归方程模拟，因此其积累过程可以大体分为2个阶段，即快速增长阶段，变化相对平稳阶段；遮光的籽粒直链淀粉和蛋白质含量变化速率具有波动性，即时而高于对照，时而低于对照；遮光对2个品种籽粒直链淀粉及蛋白质含量的影响完全相反；成熟籽粒直链淀粉与蛋白质含量呈负相关性，相关系数r=-0．81786，表明孕穗期遮光可能会对稻米的食味品质产生不利影响。     

不同生育期遮光对水稻籽粒直链淀粉及蛋白质含量的影响

研究了生育前期与生育后期遮光50%（插秧至幼穗分化期、抽穗至成熟期）对水稻籽粒直链淀粉及蛋白质含量的影响。结果表明，遮光处理的籽粒直链淀粉有着与对照相似的积累规律，而且均可以用二次曲线回归方程进行拟合。前期遮光有利于籽粒中直链淀粉的积累，提高了籽粒直链淀粉含量；后期遮光则与之相反。前期遮光不利于籽粒中蛋白质的积累，降低了籽粒蛋白质含量；而后期遮光则相反。     

接种根瘤菌和遮光对大豆固氮和光合作用的影响

【目的】研究光合和氮素互作对大豆生长和光合作用的影响。【方法】以大豆黑农37为供试材料，采用接种根瘤菌和遮光相结合的手段，测定了接根瘤菌大豆在非遮光、遮光和复光条件下的生长及光合指标。【结果】非遮光条件下，接种根瘤菌显著提高了大豆的生物量、叶绿素含量和光合能力；遮光条件下，根瘤菌发挥不出其优越性，受气孔导度和非气孔因素的影响，接菌大豆的光合速率比不接菌的对照低；恢复光照后，接种根瘤菌大豆的光合作用恢复程度也不如不接菌对照。【结论】大豆与根瘤菌的共生固氮需要在合适光照条件下才能发挥其促进生长和促进光合作用的正效应。     

不同光环境对葡萄幼苗光合产物分配与转化的影响

 以一年生京玉葡萄幼苗 (VitisvineferaL .cv .Jingyu)为试材 ,利用光合测定仪和同位素示踪技术 ,比较研究了自然光环境和遮阳环境下生长的葡萄幼苗净光合速率日变化、生物量分配、光合产物分配与转化等方面的差异。与对照相比 ,遮阳环境中生长的葡萄幼苗净光合速率日变化曲线偏低 ;叶片和茎的生物量比较高 ,根和新稍的生物量比较低 ;其光合产物分配较多流向叶片和茎 ,而向根的分配随遮阳程度的加深明显降低 ;分配到各部位的光合产物的转化利用情况也发生了不同的变化。     

遮光对小棚漂浮育苗的影响

[目的]有效解决小棚漂浮育苗不易成功的问题。[方法]用松枝(杉枝)、遮阳网、草扇进行遮光,于2002~2004年研究了遮光对小棚漂浮育苗的影响。[结果]随着遮光程度的增加,出苗率呈逐渐上升趋势,在遮光度达25.0%,出苗率接近100%,再增加遮光程度,出苗率稳定在90%以上。遮光度在20.0%~30.0%时,烟苗素质好,随着遮光程度增加,烟苗素质逐渐减弱。遮光时间从播种至小十字期比较适宜,遮光的最关键时期是刚开始出苗时。湿松枝(杉枝)遮盖棚面对烟苗出苗率效果最好,其次为遮阳网>草扇>对照。遮光能稳定小棚内温度,4种遮光方式的效果为草扇>松枝(杉枝)>遮阳网>未遮光(对照)。遮光还能有效减轻自然灾害对烟苗的伤害。[结论]透光率70.0%~80.0%的遮阳网对小棚漂浮育苗的效果最好。     

遮荫与覆盖对茶园生态环境的影响

在茶园中种遮荫树,使光照强度下降30～40%,散射辐射量增加6～15%;冬春季气温提高0.5～2.0℃;夏季气温降低0.5～4.0℃;土壤绝对含水量增加17～41%;空气相对湿度提高2～20%。用塑料薄膜覆盖茶树,也有相似的生态效应。因此,遮荫或覆盖可以提前7～10天采茶。     

Relative effects of management and environmental conditions on performance and survival of populations of a terrestrial orchid, Dactylorhiza majalis

For population viability analysis of endangered orchid populations, it is crucial to disentangle the effects of weather and management from intrinsic orchid dynamics. When doing this, typically several months’ average temperatures and/or sums of precipitations are compared with some characteristics of plant performance. Here we tested, whether short averaging intervals (1-2 weeks) are more closely correlated with orchid performance. We used 5 years of data from five Dactylorhiza majalis populations, and have shown that the improvement of prediction by shortening the interval over which the temperatures are averaged or precipitation summed, even if detectable, is only weak and not significant. This, however, may be due to low weather variability during the study. Regarding the second aspect, the effect of management (presence or absence of mowing), we have found that leaf area of D. majalis at the regularly mown site was larger than that at the sites which were mown only once in 2 years, but we did not detect a significant effect of the absence of mowing on the incidence of flowering. Mowing can affect orchid performance in two ways: by reduced shading of orchids and by reducing competition with other species. Therefore, we have determined the co-occurring species associated with presence or absence of mowing and found that shading significantly affected the length of the flower stalk, the ratio of leaf width to leaf length at the end of the season, but did not affect seed weight and probability of flowering the next year. We conclude that the most appropriate management for D. majalis is mowing at least once a year, ideally at the end of June/beginning of July, after its fruiting.     

新建茶园不同间作模式及覆盖遮阴效应比较研究——种植模式Ⅰ:茶行东西走向

研究了在东西走向的茶行中分别间作玉米、大豆、玉米+大豆以及覆盖遮阴对新建茶园生态环境、茶籽萌发、茶苗生长以及光合作用的影响。结果表明:⑴茶行东西走向以间作大豆的效果最好。间作大豆的茶园温度可降低3.1～3.6℃,光照强度降低86.4%～90.4%,日均相对湿度增加10.6%,土壤含水量增加13.0%,日均光合速率为对照的2.7倍,茶苗成活率、株高、茎粗、单株叶面积分别增加32.3%、60.5%、33.1%2、18.9%。⑵与覆盖遮阴相比,间作更能提高茶园的空气湿度。     

Effects of Drought and Shading on Non-structural Carbohydrate Stored in the Stem of Potato (Solanum tuberosum L.)

Abstract

Most studies on non-structural carbohydrate (NSC) are concentrated on the leaf and tuber, and little is known about NSC in the stem and its function. To test the hypothesis that NSC stored in stem contributes to stable tuber bulking under stress conditions, we grew plants in pots in a greenhouse under drought and shading conditions for 17 d during tuber bulking. Compared with the control, drought and shading significantly reduced leaf and stem dry weights (DW) and total NSC concentration in the main stem base. However, tuber DW increased by 77% in drought and by 46% in shading conditions relative to the control. The contributions of NSC loss in the stem to tuber DW increase in drought and shading conditions were 37% and 54%, respectively. This study suggests that NSC stored in the stem base is supplied to tuber under stress conditions to support tuber bulking.