遮阴对槭树苗期叶片生物量的影响

[目的]探讨不同遮阴程度对槭树叶面积等生长指标的影响,为槭树利用和推广提供参考依据.[方法]以青榨槭、建始槭、毛脉槭2年生扦插苗为试验材料,设全光照(处理1)、45％遮阴(处理2)、90％遮阴(处理3)3个处理,测定其叶片鲜重、干重、叶面积、水含量和比叶重等指标,分析不同遮阴程度对槭树生长发育的影响.[结果]青榨槭随着遮阴率的增加,其叶片鲜重、水含量、叶面积变化呈先降后升趋势;处理1的叶面积最大(45.19 cm2),其比叶重变化呈先升后降趋势,以处理2的比叶重最高(0.86 g/cm2);叶片鲜重、叶面积、比叶重处理间差异显著(P＜0.05,下同).毛脉械、建始槭叶片鲜重、干重、叶面积均随着遮阴率的增大而增加,且处理间差异显著;各指标排序均为:处理3＞处理2＞处理1;叶面积方面,毛脉槭和建始槭均以处理1最小,分别为22.11和41.74 cm2,以处理3最大,分别为31.94和77.21 cm2;比叶重方面,毛脉槭以处理1最高(0.74 g/cm2),处理3最低(0.61 g/cm2),建始槭以处理2最高(0.89 g/cm2),处理1最低(0.70 g/cm2).[结论]耐阴能力以毛脉槭最强,建始槭次之,青榨槭较差,因此,毛脉槭栽培在郁闭的林下更有利于其生长,建始槭适宜种植在半阴或稀疏林地内,青榨槭喜阳但能耐受一定的遮阴环境,可孤植或种植在林缘.     

不同基质、遮光度及采样时间对云南拟单性木兰的扦插生根效果

【目的】探讨不同基质、遮光度和采样时间扦插的云南拟单性木兰插穗的生根效果,为云南拟单性木兰繁殖育苗提供参考依据。【方法】2013年6、10月和2014年1、3月,将半木质化云南拟单性木兰嫩枝插穗在珍珠岩+泥炭土（3∶1）、珍珠岩、河沙、河沙+珍珠岩（3∶1）和椰糠基质上分别进行20%、50%和80%3种遮光度扦插试验,统计其生根和成活情况,分析不同基质、不同遮光度、不同采样时间对其生根效果的影响。【结果】扦插基质以珍珠岩+泥炭土（3∶1）较佳,扦插生根率达21.9%,生根数达2.1条,根长达1.8 cm;遮光50%条件下生根率最高,分别比遮光度20%、80%和对照高2.1%、13.6%和17.7%;1月采样的生根率最高,分别比3、6和10月采样的高9.4%、21.9%和24.0%。【结论】云南拟单性木兰扦插育苗以1月采样,在珍珠岩+泥炭土（3∶1）和50%遮光条件下扦插生根效果最佳。     

遮阴对海姆维斯蒂枸子叶片生理生化特性的影响

对海姆维斯蒂栒子(Cotonester hjelmqvistii Flinck and Turcz)进行遮阴处理,对其叶片中抗氧化酶活性、丙二醛(MDA)含量等进行了测定,探讨其耐阴能力.结果表明,全光照处理下MDA含量极显著低于二层(透光率17.5％)与三层(透光率8.0％)遮阴处理,与一层(透光率45.7％)遮阴处理差异不显著.随遮阴程度的增加,脯氨酸(Pro)含量依次显著下降;一层遮阴处理叶片中超氧化物歧化酶(SOD)活性极显著高于其他处理;全光照条件下的过氧化物酶(POD)活性显著或极显著高于遮阴处理.各处理下的可溶性糖含量相互间无显著差异;全光照与一层遮阳网遮阴处理的叶片电解质外渗率的差异不显著,但极显著低于两层及三层遮阴处理.综合各测定指标及形态观察认为,海姆维斯蒂枸子在全光照条件下生长发育良好,但也有一定的耐阴性,在一层遮阴处理的条件下也可以正常生长.     

不同光照对桃叶杜鹃幼苗生长的影响

采用遮阴网设计透光率分别为25%、50%、100%三种光照条件对桃叶杜鹃（Rhododendron annae）进行生理生化指标和光合指标研究,结果表明：50%透光率、25%透光率和100%3种条件下培养桃叶杜鹃幼苗90 d后,其苗高和地径的大小都为：透光率100%<透光率25%<透光率50%。桃叶杜鹃在50%光照条件下,叶绿素a、叶绿素 b 及总叶绿素含量最高,可溶性糖含量、可溶性蛋白的含量最低,各类酶活性也是最低;50%光照条件下桃叶杜鹃的光合速率极显著高于全光照和25%光照条件下的光合速率（p <0.01）,比全光条件高29.58%,比25%光照条件高166.67%;气孔导度也显著高于全光照和25%光照下的气孔导度,比全光照高14.29%,比25%光照高33.33%。     

遮阴对石灰花楸幼苗生长和光合特性的影响

以一年生石灰花楸为材料,研究了0%、67%、76%、92%4种遮阴处理下石灰花楸幼苗形态、生物量积累及分配、光合生理和叶解剖结构的变化.结果表明:遮阴使幼苗高生长、主根长减少,地径、叶面积增加;67%的遮阴能促进生物量积累,而76%、92%的遮阴则抑制生物量的积累;遮阴下根、茎生物量比降低,叶生物量比增加,比叶面积和冠根比的增加有利于增加光能的捕获.随着遮阴程度的增加,叶片厚度逐渐降低,表皮细胞变薄,栅栏组织由2层减为1层,栅海比逐渐减小,栅栏组织有向海绵组织转化的趋势;各处理叶绿素含量均显著上升,而叶绿素a/b值在2.3左右无差异性,净光合速率和蒸腾速率日变化均呈单峰曲线,没有"午休"现象,且日均值都随遮阴程度的增加依次降低.遮阴处理后,石灰花楸幼苗对弱光环境表现出了一定驯化适应性,适度遮阴有利于石灰花楸生长发育.     

Seasonal variation in resistance of chrysanthemum cultivars to Frankliniella occidentalis (Thysanoptera: Thripidae)

Seasonal variation in the level of host plant resistance can have important consequences for the repeatability of tests to measure host plant resistance to insect pests. In the present study, the levels of resistance to Frankliniella occidentalis of a susceptible and a partially resistant cultivar of chrysanthemum, Dendranthema grandiflora, were determined throughout the year. Thrips damage, reproduction and adult female survival were determined on excised leaves in Petri dishes under uniform conditions. Strong seasonal fluctuations were observed in these three characteristics. On leaves from plants grown in winter, damage, reproduction, and survival were higher than on leaves from plants grown in summer. Clear differences in resistance were observed between the susceptible and the partially resistant cultivar on leaves from plants grown in winter, while differences disappeared in summer. Damage on both cultivars and survival on the susceptible cultivar were negatively correlated with mean daily solar radiation during plant growth, suggesting that the level of resistance depends on light intensity during plant growth. This was confirmed in an experiment carried out in summertime with shaded and unshaded plants. Leaves from control plants, grown under high light intensity had a higher level of resistance than leaves from shaded plants grown under reduced light intensity. There were clear differences in resistance between the cultivars under shaded conditions (low light intensity), but not under unshaded control conditions (high light intensity). This revised version was published online in July 2006 with corrections to the Cover Date.     

太阳能平板型集热器阵列排布优化

为了优化集热器阵列排布便于水平屋顶有限空间的安装,该文建立了日均遮挡模型和太阳辐射模型。利用所建模型研究了集热器阵列排布长宽比与纬度、日均遮挡因子、阵列占地面积、到达集热阵列的太阳辐射量间的关系。结果表明,大型集热器阵列(占地面积≥500m2),冬至日日均遮挡因子随阵列长宽比和纬度的增加而增大。长宽比∈[1/10,3/1)时,日均遮挡因子上升较快;长宽比∈[3/1,10/1]时,日均遮挡因子增加平缓。对于占地面积∈[50,1000]m2的集热器阵列,面积越小、日均遮挡因子随长宽比的变化越快。冬半年各月水平面上日均太阳辐射分布情况对到达阵列的太阳辐射量最大对应的最佳长宽比存在较大影响。鉴于太阳辐射分布的影响以及便于工程应用,文中给出了中国不同纬度13个城市5种集热器阵列的最佳长宽比;研究结果可为太阳能集热阵列的排布优化提供参考。     

Relation between growth conditions and dormancy of seed potatoes. 3. Effects of light

Summary The effects on the dormancy of progeny tubers of the timing and level of shading during plant growth were investigated in three field experiments. The tubers were harvested while immature. Shading (50–75%) the crop shortly before haulm pulling shortened dormancy by 5–7 days in two experiments. However, dormancy was hardly affected by 50% shading in one experiment, carried out in a sunny dry period. The effects of the photoperiod during tuber bulking on dormancy were studied in two indoor experiments. Plants were grown at 18/12°C (day 12h/night) and a 12 h photoperiod. Shortly after tuber initiation, the photoperiod was extended to 18 h for 4–6 weeks by photosynthetically inactive incandescent light, or kept at 12 h. The effects of the photoperiod on dormancy were up to 9 days, but differed between the cultivars and experiments. Generally, the effects on tuber dormancy of differences in growth conditions, as reported in this series of papers, were limited.     

遮光颜色对夏季北方茶园的影响

为探究夏季高温时节遮光颜色对北方茶产量品质及茶园微气候环境的影响,通过黑、红、银灰、绿、蓝、黄6种颜色遮阳网覆盖处理与露地CK相比较,分析茶园温湿度、茶树光合作用、茶叶产量品质等参数的变化差异.结果 表明:与露地CK相比,黑色、银灰色、蓝色遮阳网下降温增湿效果最好,红网、蓝网、黄网覆盖对茶树光合作用的促进效果较为显著;...     

遮荫和施肥对一叶兰生长的影响

以一叶兰为材料,通过大田试验,研究了3个遮荫水平与4种施肥方式对一叶兰生长性状、叶片叶绿素SPAD值及植株养分含量的影响。试验结果表明:遮荫70.5%的条件下,一叶兰的叶片数、叶片长、叶片宽和株高均优于遮荫87.5%、94.8%,94.8%的遮荫条件下叶片叶绿素SPAD值最高;每3个月施复合肥60 g/m2时一叶兰的长势最好,适当的增施氮肥和钾肥,有利于一叶兰的生长发育。