香花槐容器育苗技术初步研究

2003年春在山西太岳林局进行了香花槐种根容器育苗试验，大棚容器育苗与田间容器育苗对比研究结果表明，大棚育苗明显优于田间育苗，前者种苗的平均高、地径、生根数、主根长分别比后者提高了269．8%，5．91%，84．79％，75．6%。笔者认为，大棚容器育苗是快速培育香花槐优质种苗的有效途径，并就这一技术作了简要介绍。     

干旱胁迫下早稻幼苗特异性表达cDNA的筛选

以生长在特殊环境中（26℃、12h／12h光／暗周期、光强2500lx）的早稻297二叶一心期幼苗为材料，构建了干旱胁迫诱导表达差减文库。以干旱为处理，而有水状态为对照。通过筛选差减文库，共获得了141个克隆。分析表明，差减文库建立成功。     

抛秧水稻生长发育与产量形成的生态生理机制——I．活棵立苗及其生态生理特点

针对抛秧持有的秧苗直立过程，以洗根手插为对照，研究了抛秧稻活棵立苗及其生理生态特点。结果表明，抛秧稻带土秧苗抛后，平躺小苗、中苗、大苗一般分别在2－5、5－6、7－10天内直立。在活棵立苗期间抛秧稻苗体内水分、养分及肖合等状况明显优于同质洗根手插苗。根、叶、蘖等生长在数量、质量上也优于同质洗根手插苗。抛秧稻缓苗恢复的先后顺序为发根、出叶速度加快，体内养分含有率及干物重的递增。秧苗素质、苗龄、带土状况、苗姿以及水、温等一些内外因素均对抛秧稻活棵立苗有不同程度的间接或直接影响。     

7种芸香科种子的发芽试验

试验表明芸香科种子不耐贮藏；除枳壳种子在30℃下萌发最佳外，金桔、红桔、芦柑、甜橙、九里香及花椒均以20～30℃变温为最适萌发温度；花椒种子存在休眠现象，冷湿处理及外源GA可解除休眠促进萌发；在金桔及红桔种子中发现有白化苗。     

不同浓度多效唑对烟苗生长发育的影响

为探索多效唑对烤烟壮苗培育的影响,以‘湘烟3号’为材料,当烟苗处于大十字期时,用不同浓度的多效唑进行喷施处理,研究了烟苗农艺性状和生理特性的变化。结果表明:喷施不同浓度多效唑可明显降低烟苗的株高、最大叶面积,增加茎粗,提高根冠比和干鲜比,同时烟苗根系活力、叶绿素、可溶性糖均极显著增加,SOD和POD活性也明显提高,丙二醛含量减少,其中以100mg/L多效唑处理农艺性状和生理特性综合表现最优,较之CK,株高和最大叶面积分别缩小了3.2cm、17.7cm2,茎粗、根冠比、干鲜比上升了12.1%、56.1%、24.7%;根系活力、叶绿素、可溶性糖提高了50.8%、41.9%、33.0%;SOD和POD活性增加了0.38、0.32倍;丙二醛含量减少1.687nmol/g。说明喷施多效唑能有效抑制烟苗地上部分的生长,促进根系生长和根茎叶协调生长,有利于培育壮苗。     

镉对小麦幼苗的生长和生理生化反应的影响

镉对小麦幼苗和根系生长有抑制作用,尤以对根系的抑制更为显著,但镉浓度为5ppm时,有刺激生长的作用.幼苗的脯氨酸和可溶性蛋白质含量随镉浓度的增加而增加,尤其在高浓度镉下脯氨酸含量剧增,电解质外渗率也明显增大.镉使胚乳中的α-淀粉酶活性降低,这种效应随镉浓度增高而加强,随幼苗的生长却趋于减弱.镉诱导根的正、负极向过氧化物酶同工酶产生新谱带,并使原有的一些谱带活性增强.上述结果显示出镉使小麦幼苗的细胞结构和功能受到损害,而小麦幼苗对镉害也表现出一定的适应性保护反应.     

Dark induced senescence as a tool in breeding wheat for optimum senescence pattern

Senescence can influence: (1) leaf area duration, (2) area of transpiringtissue and (3) translocation of nutrients – mainly nitrogen to grain.Therefore, selection for optimum senescence pattern might be efficient forimproving performance of wheat in a given environment. This study wasconducted to investigate the feasibility of a seedling test for estimatinggenotypic differences in senescence rate of wheat. We studied the responseof several wheat genotypes to dark exposure of seedlings, by measuring therate of chlorophyll loss in the first leaf. The rate of chlorophyll loss variedsignificantly among genotypes, the highest rate being more than double ofthe lowest. Linear regression accounted for most of the chlorophyll contentvariation during dark treatment in all cultivars. Significant correlation wasfound between the rate of chlorophyll loss following exposure to darknessand chlorophyll loss during aging in an environment relatively free ofdiseases and stresses. A good correlation was also found between theresponse of several genotypes to dark exposure and chlorophyll loss ofseedlings following starvation. We conclude that a seedling test for darkinduced senescence might allow an easy characterization of senescencepattern, allowing increased genetic progress in its optimization.     

Evaluation of resistance to Fusarium head blight in indigenous Japanese species of Agropyron (Elymus)

General (GSI) and specific (SSI) selection indices were constructed for three open-mating populations of sugarcane (Saccharum spp.) seedlings and their ratoon stages. Though specific indices were found to be the most effective in improving mean brix yield in their own source populations, but the GSI was better to SSI in other populations as indicated by higher mean values and more number of superior clones at selection and evaluation stages. This indicated the wider applicability of the GSI over SSI. Inspite of better expected genetic advance through GSI in ratoon crop, the actual gain in brix yield attained, through GSI, was better in seedlings. This revised version was published online in July 2006 with corrections to the Cover Date.     

不同浓度盐胁迫对转基因饲用甜菜种子萌发及幼苗生长的影响

通过不同浓度NaCl溶液处理转基因饲用甜菜种子及其幼苗试验，研究了盐胁迫下种子萌发、幼苗生长及胁迫解除后种子的效应，为盐土农业生产提供理论依据。结果表明，转基因饲用甜菜种子萌发的适宜Nacl浓度为50。150mmol/L，其中100mmoL／LNaCl胁迫下，种子发芽率最高，与对照相比高6．78％。随着盐胁迫浓度的升高，种子萌发延迟，萌发率也呈不同程度的降低。盐胁迫解除后，种子萌芽迅速，萌芽率提高，整齐度增加。转基因饲用甜菜幼苗在不同NaCl浓度胁迫下表现出的反应不同，高盐胁迫对抑制幼根生长影响较大。     

玉米苗期的耐冷性状及其遗传力的研究

本文利用6个自交系按6×6不完全双列杂交组配的15个F_1为材料,对出苗率、出苗指数、电解质外渗量等11个与玉米苗期耐冷性有关的性状进行通径分析和遗传分析表明:在所有被测性状中,出苗率、出苗指数、幼苗鲜重、干物质增长量、组织活性对玉米幼苗耐冷性的影响是直接的,幼苗干重、种子百粒重、电解质外渗量对玉米苗期耐冷性的影响是间接的;出苗率、出苗指数、幼苗干重、干物质增长量四性状在遗传上主要受加性效应影响.根据以上结果提出,上列性状都应作为玉米耐冷性育种的改良目标.