沙引发对紫花苜蓿种子盐逆境下发芽及幼苗生理生化变化的影响

试验以紫花苜蓿品种维多利亚和金皇后种子为材料，研究了沙引发处理对高盐(0．8％NaCl)逆境下种子发芽及幼苗生理生化变化的影响。结果表明，沙引发处理能显著提高紫花苜蓿两个品种种子的发芽率、发芽势、发芽指数和活力指数，缩短平均发芽时间，显著增加幼苗干重，同时提高了过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性，减少丙二醛(MDA)的积累。说明沙引发提高了紫花苜蓿种子的活力和抗盐胁迫能力，促进了盐逆境下种子的萌发和幼苗生长。     

盐胁迫下5-磺基水杨酸、水杨酸对小黑麦种子生理特性的影响

采用种子萌发试验,研究了5-磺基水杨酸、水杨酸对盐胁迫下小黑麦种子萌发及幼苗生长情况的影响.结果表明:在盐胁迫下,适当浓度的两种酚酸均能提高小黑麦种子萌发的发芽率、发芽指数、活力指数,浓度增高则抑制种子萌发.适当浓度的两种酚酸还能降低幼苗叶片电导率和丙二醛(MDA)含量、提高叶绿素含量.总的看来,5-磺基水杨酸的效果比水杨酸好,且低浓度的效果比高浓度的好.     

粤选1号匍匐翦股颖新品系果岭草坪 夏季性状及高温胁迫效应

粤选1号匍匐翦股颖新品系是丛Penncross建坪的老果岭中分离出的无性系。在广州地区夏季果岭草坪密度、绿叶盖度、叶片老化指数、抗坏血酸含量显著高于原品种Penncross，叶片质膜相对透性低。持续高温(36℃)胁迫下，新品系叶片中游离脯氨酸含量显著增加，而原品种在高温胁迫第3d才开始显著增加，新品系游离脯氨酸含量明显高于原品种；高温胁迫下新品系叶片可溶性蛋白含量增加并高于Penncross，而Penncross在高温胁迫2d后显著下降；新品系匍匐茎可溶性糖含量增加，高温胁迫5d后，Penncross显著高于新品系；新品系匍匐茎淀粉含量显著高于Penncross；高温胁迫对叶片相对含水量和叶绿素含量无明显影响。     

湿地松优良半同胞家系蛋白质及糖类对水分胁迫的生理响应

为研究湿地松优良半同胞家系蛋白质及糖类对水分逆境的生理响应，采用盆栽试验和吸光度测定结合的方法，以湿地松普通种子为对照（CK），测定了七个湿地松半同胞家系在正常水分状态（土壤相对含水量为70%）、弱度水分胁迫（土壤相对含水量为55%~60%）、中度水分胁迫（土壤相对含水量为35%~40%）和强度水分胁迫（土壤相对含水量为20%~25%）条件下的可溶性蛋白质、还原性糖、可溶性糖的含量，研究结果表明：无论是不同水分梯度还是不同家系水平，蛋白质、还原性糖、可溶性糖含量的差异均达极显著性水平。随着水分胁迫程度的加剧，各家系蛋白质含量呈先升后降的趋势，在水分胁迫初期，各家系蛋白质含量增加，水分胁迫中、后期各家系蛋白含量呈直线下降；随着水分胁迫的加剧，各家系还原性糖、可溶性糖含量呈直线上升。家系1027、101、464在水分胁迫条件下具有较高的可溶性糖含量，其抗旱性较其它家系要强，是这三个家系速生、高产的生理原因之一。     

NONLINEAR COUPLING IN THERMOELAST1C THEORY AND A SOLUTION TO THE PROBLEM IN THE HALF SPACE

It's recommended that the term coupled in temperature and strain is nonlinear and is significant in thermoelastic theory. Using the solution of linear coupled and uncoupled theory and selecting appropriate general coordinates, authers approach the nonlinear coupled problems with a variational method. A solution to the problem in half space, is given. It is shown that the difference between the nonlinear coupled theory and the linear coupled or uncoupled theory would be notable when the amplitute of temperature is much larger than that of the reference slate.     

Analysis on Longitudinal Cracks and Deflection of the Pre-stressed V-shape Slab Roof Structure

In this paper, the finite element method is used to analyze the behavior of the prestressed V-shape Slab Roof structure, especially the effect of temperature change on the stress of slab. The calculated results indicate that when the temperature changes, the tensile stress at the lower extreme fibers of the flange plate near rib exceeds the tensile strength of concrete subjected to the combined action of triaxial stresses and results in the longitudinal cracks of the flange plate. The deflection analysis is based on the mechanical model of the prestressed V shape slab with the longitudinal cracks. The calculated results are in general agreement with the field observations.