高温胁迫对不同甜瓜品种幼苗生长和生理特性的影响

在高温逆境胁迫下对16个甜瓜品种幼苗的生长发育、生理代谢和叶绿素含量进行了研究。结果表明:高温胁迫下,16个甜瓜品种植株生长均受到不同程度的影响,叶绿素含量降低,耐热性强的品种降幅较小;SOD活性和脯氨酸含量变化趋势基本一致,高温处理后与对照比较均升高,而耐热性较差的品种POD活性和可溶性蛋白含量降低。耐热性比较分析表明,2个品种的耐热性较强,4个次之,中等程度耐热品种7个,热敏感品种3个。     

水稻机械化插秧标准模架育秧技术研究

通过制作模架改变机械插秧育秧方式,既解决了软、硬盘育秧投入成本高,又解决了双膜育秧切块费工,切块成型标准难掌握、边角碎料多,种、肥、土浪费大的弱点。使水稻机械化插秧育秧成本低,投资少,操作简单,管理方便,秧板利用率高。     

广西银杏实生苗培育技术

该文对广西银杏实生苗的培育技术进行介绍,关键要选壮苗,选有胚芽且胚乳大的种子,采用砂藏、加湿、加温,对苗圃地进行细致整地,施足有机肥,3月播种,出苗后适当遮阳,及时除草、防病、追施叶面肥,出圃前30d炼苗,起苗后按标;位分级、捆扎,填写苗木标签,并建立苗木档案。     

Effect of hardening on frost tolerance and fatty acid composition of leaves and stems of a set of faba bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.) genotypes

Frost tolerance is a main component of winter-hardiness and improving it would promote faba bean (Vicia faba L.) cropping in cool-temperate regions. In many species, leaf fatty acid composition was found to be related to frost tolerance. The objective of this study was to determine, in a representative sample of genotypes, the effect of hardening on leaf and stem (1) frost tolerance and (2) fatty acid composition, and to seek correlations between them. First leaf, second leaf and stem of 31 faba bean genotypes were analyzed after hardening and without hardening. High frost tolerance of known winter genotypes and several experimental lines was shown. Hardening had a significant, positive effect on frost tolerance of all three organs. Stems were on average more frost tolerant than leaves. Hardening induced significant changes in the fatty acid composition: oleic acid decreased significantly in leaves by 3.24% and in stems by 1.77%, whereas linolenic acid increased in leaves by 6.28% and in stems by 9.06%. In stems, correlations between frost tolerance and fatty acid composition were not significant. Correlation coefficients strongly indicated that non-hardened oleic acid content, changes in oleic acid and in linoleic plus linolenic acid content in leaves partly explained their frost tolerance; 0.347 (P < 0.1) < |r| < 0.543 (P < 0.01). The results corroborate the importance of using genetic differences in the fatty acid metabolism in breeding grain legumes for frost tolerance.     

碱胁迫对紫荆幼苗生长与光合作用的影响

通过在碱胁迫下对紫荆生长及光合作用的研究,结果表明:紫荆是具有较强耐碱性的园林树种,随着Na2CO3处理浓度的增加,幼苗成活率、植株鲜质量及地上部与地下部的质量比逐步下降;叶片中膜相对透性、MDA、可溶性糖等指标均有增加;净光合速率、细胞气孔导度、细胞间CO2体积分数、蒸腾速率、叶绿素质量分数等逐步递减。当碱浓度达到481.32mmol·L-1为半致死浓度,当浓度达200.64mmol·L-1为致死浓度。     

Establishment,survivorship, and growth of yellow birch seedlings after site preparation treatments in large gaps

The occurrence of yellow birch (YB) in the northeastern forests of North America is a source of concern. Several guidelines suggest ways to favor the regeneration of this species, including creating openings from small gaps to large clearcuts, coupled or not with a variety of soil preparation treatments. However, it is not clear if soil preparation treatment favors YB establishment by simply increasing the availability of good seedbed types, or by also altering competition pressure exerted by interfering species during the period of seedling establishment. For this study, large gaps (900 m²) were created in a 70-year old YB dominated forest, to which three treatments differing in soil disturbance intensities were applied (i.e., soil scarification (i) using a rake [raking]; or (ii) by dragging slash out to the edges of the gap [slash drag]; and (iii) limited to the passage of the harvesting equipment [control]). The proportion of seedbed types reportedly most favorable for YB establishment (i.e., mineral-dominated) increased as the severity of the site preparation increased. The opposite was observed for organic-dominated seedbeds. As a result, the stocking of YB seedlings increased with the severity of site preparation. However, YB stocking was deemed sufficient in all gaps to ensure future canopy dominance, even in the control treatment. Although YB seedlings generally achieved greater heights as site preparation intensity increased, it was clear that this did not reflect vigorous growth as, on average, greater heights coincided with greater seedling height–diameter ratios. At the seedbed level, height–diameter ratio was associated with an increase in surrounding competition pressure and an increase in the incidence of stem apical death (SAD), which in turn decreased height differences among seedbed types by the end of the study. At the gap level, this blurred the advantages of site preparation over a laisser-faire strategy. The incidence of SAD was greatest in the slash drag and the rake treatments. Consequently, we cannot say that intense soil scarification is worth the expenses, especially in stands where YB seed sources are abundant.     

外生菌根菌对红松苗木生长的影响

采用沟施接种方法对3年生红松苗木进行野外单接种及混合接种的试验结果表明：菌株010和菌株025为供试菌株中对红松苗木生长促进效果最佳的菌株,与对照相比,高生长分别提高19．57％和17．04％,地径生长分别提高13．64％和15．91％。接种菌株组合GT001／GT005的苗木高生长仅比对照提高3．80％,其他3个菌株组合的高生长均低于对照;地径生长与对照相比提高0～9．10％。与单接种相比,仅接种菌株组合GT001／GT005苗木的高生长高于单接种菌株GT001和菌株GT005的苗木;接种菌株组合044／009苗木的地径生长介于单接种菌株044和菌株009的苗木之间,而接种其他3个菌株组合苗木的地径生长均低于各自单接种的苗木。     

大果榉结实、种子和幼苗特性研究

为了解大果榉结实、种子和幼苗特性,为大果榉繁育和推广利用提供理论依据及苗木生产基础,对大果榉的结实和种子特性进行了一些基础研究。结果显示:大果榉结实大小年明显,结实率低;沙藏层积处理大大提高了大果榉种子出芽率和整齐度;大果榉幼苗的分杈不仅极普遍,而且分杈高度低,分杈开始时间早。这些结果对大果榉的种子繁育和推广利用具有一定的理论和生产实际意义。     

小麦秸秆与菇渣混合基质对黄瓜秧苗质量的影响

采用腐熟小麦秸秆和食用菌菇渣为原料,组成7种复合基质进行黄瓜穴盘育苗。结果表明,腐熟小麦秸秆∶菇渣=3∶1（体积比）是黄瓜育苗的最佳配比基质,不但出苗率高,植株生长健壮,而且成本低,整个苗期不用施肥,可用于育苗和绿色蔬菜生产。     

葡萄糖对拟南芥种子萌发和幼苗生长的影响

以拟南芥为试验材料,在不同浓度葡萄糖胁迫下,对种子萌发、幼苗根生长进行研究。结果表明,50 mmol/L葡萄糖对种子萌发率没有影响,且促进了幼苗根生长;随着浓度增加,种子萌发和幼苗根生长受到了抑制,侧根数目开始增加,在300 mmol/L下,幼苗生长受到了明显抑制;同时对幼苗进行细胞膜透性、丙二醛(MDA)含量测定,发现在50 mmol/L葡萄糖胁迫下,二者的含量并没有增加,甚至降低,但随着葡萄糖浓度增大,又明显升高,这说明葡萄糖能够参与植物生长发育的调控。