杂交早稻吸氮特性与产量形成的初步研究

研究了在不同施氮水平下,杂交早稻吸氮特性及其与产量形成的关系。结果表明;杂交早稻威优49亩产500千克左右,植株每亩总吸氮量平均为9.78千克,其中土壤供氮量占52.45%。杂交早稻一生中前期吸氮量占50.72%,中期占31.08%,后期占18.30%,以中期施氮对叶片含氮率影响最大。在高氮水平下,中期施氮导致茎鞘醣含量急剧下降。抽穗前植株吸氮量与每亩发育颖花数呈极显著正相关,但结实率受每朵颖花占有抽穗前醣量的影响。最适 LAI 为6.5～7.5。     

家畜的遗传疾患和异常

本文综述了家畜遗传疾患和异常的发生概况,而对主要遗传病患和异常按常染色体隐性遗传、常染色体显性遗传、性连锁遗传、染色体数目和结构的异常等分别进行了描述,分析了发生的可能原因及危害,提出了防止遗传疾患发生和扩散的措施。     

东北葱属植物的研究

本文记载东北地区产葱属植物共计２４种２变种１变型，报道其中１１种的染色体数目，并对一些分类学问题进行了讨论，为该属植物的进一步研究提供资料。     

小佛肚竹竹丛结构对新竹秆形变异的影响

竹丛结构状况直接影响着竹子的生长环境。通过丛初植立竹数、立竹空间分布和丛立竹数等对小佛肚竹Bambusa ventricosa秆形变异的影响进行研究。结果表明：新竹畸形秆率随丛初植立竹数和栽植后年份的增加而降低,丛初植立竹数以2～3株为宜;出笋后的丛立竹数与竹丛外围、内围新竹数分别呈正相关和负相关,与新竹畸形率呈负相关;竹丛畸形秆新竹数随丛立竹数（出笋前）增加呈先升后降的趋势,丛立竹数与新竹畸形率呈负相关,人工栽培的丛立竹数应控制于4～6株。图1表2参10     

徐州云龙山侧柏林细根形态与分布规律研究

为了提高徐州市石灰岩山地侧柏人工林的生态和景观质量,该研究以云龙山侧柏人工林为对象,利用Win-RHIZO根系分析仪对2个样地不同土层深度细根的形态参数、比根长、根长密度和生物量进行了综合分析。结果表明：（1）细根直径随根序等级的升高而增加,细根长度、比根长、表面积表现为下降趋势,而细根体积表现为先减小后增加的趋势;（2）在不同立地条件下,细根长度、比根长、表面积和体积均表现为表层高于底层,东坡高于西坡的规律;（3）单位面积上细根的生物量随根序的升高而增加,而根长密度则明显下降;表土层中细根生物量和根长密度都要高于底层,东坡高于西坡。     

不同水分条件下不同抗旱性苦荞根系生长规律研究

为了探明不同抗旱性苦荞根系形态和生理特性与抗旱性的关系,为干旱胁迫下苦荞高产优质栽培管理及抗旱品种的筛选提供理论依据,采用人工控水的方法,研究并分析了正常供水、重度干旱条件下不同抗旱性苦荞品种迪庆苦荞（耐旱）、黑丰1号（旱敏感）根系生长形态和生理指标变化。结果表明,干旱胁迫显著增加了苦荞根冠比、根系丙二醛（MDA）和脯氨酸（Pro）含量,而最大根长、根体积、根表面积显著降低。随着生育期推进,各处理苦荞最大根长、根体积、根表面积、MDA含量等指标均呈现逐渐增加趋势,根冠比、Pro含量呈现先增后减趋势。品种之间方差分析结果表明,重度干旱胁迫条件下,各测定时期迪庆苦荞的根冠比、最大根长、根体积、根表面积、根系Pro含量均显著高于黑丰1号,MDA含量则显著低于黑丰1号。回归分析表明,不同处理苦荞根表面积、最大根长等指标在测定时期内随时间变化的数学模型均符合指数函数,根体积、MDA含量等指标均符合一元二次方程的规律。干旱胁迫下苦荞根系与地上部分的生长均受到抑制,且表现为对地上部的影响大于对根系;与黑丰1号相比,迪庆苦荞耐旱性更强。     

青霉菌发酵液对大豆幼苗生长及生理特性的影响

采用室内生理检测及生物化学方法,研究了青霉菌发酵液对大豆幼苗生长及生理特性的影响。结果表明:用一定浓度的青霉菌发酵液对大豆浸种和茎叶处理,大豆幼苗的生长呈明显上升趋势,处理后大豆的株高、根长、株鲜重和根鲜重均明显得到了提高,且生长状态好于对照,不同浓度处理间具有明显差异,在发酵液浓度为5 g·L-1时,效果最佳。尤其是对根鲜重的影响,促进率最高可达56.21%,同时增强了幼苗根系活力,最大可以提高57.82%,浸种和茎叶处理后,分别提高了叶绿素含量41.25%和15.40%;超氧化物歧化酶活性12.20%和11.70%;过氧化物酶31.33%和29.95%;过氧化氢酶活性42.8%和20.0%,这为发酵液在大豆田推广应用、提高大豆产量提供了重要理论依据。     

Combined mutations in five wheat STARCH BRANCHING ENZYME II genes improve resistant starch but affect grain yield and bread-making quality

Increases in the proportion of amylose in the starch of wheat grains result in higher levels of resistant starch, a fermentable dietary fiber associated with human health benefits. The objective of this study was to assess the effect of combined mutations in five STARCH BRANCHING ENZYME II (SBEII) genes on starch composition, grain yield and bread-making quality in two hexaploid wheat varieties. Significantly higher amylose (∼60%) and resistant starch content (10-fold) was detected in the SBEII mutants than in the wild-type controls. Mutant lines showed a significant decrease in total starch (6%), kernel weight (3%) and total grain yield (6%). Effects of the mutations in bread-making quality included increases in grain hardness, starch damage, water absorption and flour protein content; and reductions in flour extraction, farinograph development and stability times, starch viscosity, and loaf volume. Several traits showed significant interactions between genotypes, varieties, and environments, suggesting that some of the negative impacts of the combined SBEII mutations can be ameliorated by adequate selection of genetic background and growing location. The deployment of wheat varieties with increased resistant starch will likely require economic incentives to compensate growers and millers for the significant reductions detected in grain and flour yields.     

PEG胁迫对不同小麦品种幼苗抗旱生理指标的影响

为给小麦抗旱育种的早期筛选工作提供理论依据,以济麦262(抗旱型)、烟农19(中间型)和临麦2号(水分敏感型)为材料,采用PEG模拟干旱胁迫,探究干旱胁迫对不同小麦品种幼苗生物量、含水量、根系形态特征、抗氧化酶活性和叶绿素荧光参数的影响。结果表明,PEG胁迫下,三个品种中济麦262的生物量最大,地下部含水量显著高于临麦2号和烟农19;其根系的总长、总投影面积、总面积和总体积最大,且受抑制程度最低;其抗氧化酶活性在一定程度上明显增强,尤其是叶片和根系过氧化物酶、根系超氧化物歧化酶及叶片过氧化氢酶活性增强幅度显著高于临麦2号和烟农19;其叶片光化学荧光淬灭系数(qP)和PSⅡ的实际光化学效率与CK相比均呈下降的趋势,其中qP下降程度最低,荧光非光化学淬灭显著增强且高于其他两个品种。综上所述,在PEG胁迫下抗旱品种的生长受抑制程度最小,清除氧自由基能力较强,光能利用率高。     

Control of Helminthosporium leaf blight of spring wheat using seed treatments and single foliar spray in Indo-Gangetic Plains of Nepal

Four fungicides for seed treatments and one as foliar spray were tested in replicated field experiments in a strip plot design to determine the effect of fungicides on Helminthosporium leaf blight (caused by Cochliobolus sativus and Pyrenophora tritici-repentis) severity and grain yield of wheat. Wheat seed cv. RR 21 was treated with fungicides, carbendazim (Areestin), triadimenol (Baytan), tebuconazole (Raxil), and carboxin + thiram (Vitavax 200B). Single foliar application of propiconazole (Tilt) was sprayed at flowering stage. Controls were included for both factors and treatments were replicated four times. Triadimenol and carboxin + thiram increased seed germination in both years. Triadimenol, tebuconazole, and carboxin + thiram reduced the number of infected seedlings and seedling root rot severity in both years. Number of tillers was higher in carboxin + thiram treated plots compared to other seed treatments. Compared to the control, carboxin + thiram increased grain yield by 9% and 8% in 2004 and 2005, respectively, and triadimenol by 6% in both years. The foliar spray of propiconazole significantly reduced Helminthosporium leaf blight severity and increased thousand-kernel weights. Propiconazole spray increased grain yield by 15% and 14% in 2004 and 2005, respectively. Therefore, seed treatment either with triadimenol or carboxin + thiram in combination with single post-flowering foliar spray of fungicides should minimize grain yield loss due to wheat foliar blight in South Asia. The findings of this study could be useful in developing strategies to manage Helminthosporium leaf blight in South Asia and other warm wheat growing regions of the world.