筇竹种子特性及实生苗生长发育规律的研究

本文对筇竹种子特性和实生苗的生长发育规律进行了系统研究。结果表明 :1筇竹的种子长 1.0 4～ 1.4 5 cm ,直径为 0 .6 9～ 1.14cm:种子净度为 92 .2 6 %、千粒重 5 0 2 .95 g、发芽率 92 %、含水量达 70 .18% ;种子休眠期短、不耐贮藏 ;2二年生实生苗高 39.38cm、地径 0 .2 8cm、竹鞭长 39.38cm ,根系发达 ,分蘖能力强 ,笋芽多达 15个 /丛 ,可在秋季出圃造林 ;3天然更新差、竹苗生长不良是筇竹濒危的原因之一。     

Effect of collection date on capsule moisture content and germination of Populus ciliata Wall. ex Royle from central Himalaya

Seed maturity indices of Populus ciliata were investigated in collections from Sukhatal and Bhowali. Across both seed sources, mean capsule size varied from 68.0±1.5 mm² to 72.0±0.9 mm², while mean number of capsules/100 grams varied from 268±8 to 295±12. Mean weight of 100 capsules varied from 25.0±1.4 g to 27.0±1.4 g. Weight of 100 capsules among sources and individual trees differed significantly (P < 0.05), while number of capsules/100 grams and weight of 100 capsules was negatively correlated (r² = 0.69). As capsules matured moisture content decreased from 83.2±1.1% to 54.3±0.3% at Sukhatal and from 77.7±0.4% to 46.4±0.3% at Bhowali. The optimum germination was at 58–60% moisture content. Maturation was related to capsule colour changes as well as moisture content. These parameters were judged to be good indicators of when to collect P. ciliata seeds.     

核桃种子烂种原因及发芽条件的研究

对核桃种子的采集时间、调制方法、浸种和催芽技术等几个方面进行了系统研究，并进行了种子生理学的测定，其目的是探明核桃种子的烂种原因和发芽条件。结果表明，采种过早和堆沤过久都会引起种子霉烂，而种子吸水不足则是导致沙藏烂种和播种烂种的主要原因。同时也查明，种壳的机械约束是种子发芽慢的主要原因，较高的环境温度和充足的种子含水量是核桃种子发芽的适宜条件。采取适当晚采，合理调制和沙藏前适当浸种，播种前晒裂种壳，播种后提高地温等措施，可以减少烂种，加快出苗速度，提高出苗率。     

浙江12种杜鹃花属植物的果实形态、种子数及其相关性研究

杜鹃花属(ＲｈｏｄｏｄｅｎｄｒｏｎＬ.)的系统学研究尚有许多值得探索的问题(余树勋,1986;闵天禄等,1990;Ｐｈｉｌｉｐｓｏｎｅｔａｌ.,1973)。近年来,本课题组陆续对浙江杜鹃花属植物开展了分类学和形态学的研究(丁炳扬等,1987;1989;1990;1995)。本文就浙江12种野生杜鹃花属植物的果实形态、种子数及其相关性进行研究,为该属的系统学研究及引种驯化提供理论依据。1　材料与方法11　常绿杜鹃亚属(ＳｕｂｇｅｎＨｙｍｅｎａｎｔｈｅｓ)　　云锦杜鹃(Ｒ.ｆｏｒｔｕｎｅｉＬｉｎｄ1.)、猴头杜鹃(Ｒ.ｓｉｍｉａｒｕｍＨａｎｃｅ)、安徽杜鹃(Ｒ.…     

Seed Size as a Predictor of Germination Success and Early Seedling Growth in ‘Hollong’ (Dipterocarpus macrocarpus Vesque)

In species with seeds losing viability shortly after dispersal and exhibiting inherently low germination, quick decisions are required with respect to seeds that should be selected to maximize germination success and vigorous growth of seedlings. In ‘hollong’ (Dipterocarpus macrocarpus Vesque), I address the following questions: (a) are seeds that germinate randomly distributed within a seed population, (b) are subpopulations of viable and non-viable seeds separable, (c) does seed size predict which seeds germinate and (d) does seed size predict time required for germination and seedling vigour? Two estimators of seed size, diameter and weight, demonstrated a significant positive linear relationship endorsing assumption that accumulation of mass increases with increase in diameter of seeds. A threshold for selection of potential seeds for germination could not be derived from diameter measurements since seeds in an entire range of diameter did or did not germinate. All seeds <11 g did not germinate, but this threshold lies at the far lower end of the weight range and allows rejection of only a few seeds and acceptance of many seeds that will not germinate. A risk of potential seeds being rejected or non-viable seeds being picked exists if selection was derived from either diameter or weight. However, viable seeds could be better predicted from a scatter-plot of diameter on x-axis and weight on y-axis. Seeds showed a fan-shaped scatter and those developing the lower blade of the fan did not germinate while those following the handle were successful. Hence, two subpopulations segregated, but with a fuzzy edge. Mean diameter and mean weight of germinated seeds were significantly greater than those of ungerminated seeds. Most ungerminated seeds were those that had relatively smaller weight compared to their diameter. Although some large diameter seeds with small weight did germinate, but failed to develop into seedlings. Germination time and seedling vigour parameters (height, leaf number and collar diameter) were correlated both with diameter and weight. However, weight appears to have mattered more than diameter in germination success and early seedling growth.     

Effects of seed water content and storage temperature on the germination parameters of white spruce, black spruce and lodgepole pine seed

The effect of seed water content (WC) (2–3, 5–6 and 22–25%, on a fresh weight basis), storage temperature (+4, −20, −80 and −196°C) and storage duration (6, 12, 24, 48 and 60 months) on the germination of white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) B.S.P.) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) seed was investigated. Germination of white spruce control (untreated) seeds and seeds adjusted to 2–3% and 5–6% WC declined after 48 months of storage at −80 and −196°C, with a further decline at 60 months at −20, −80, −196°C. Germination remained high when control white spruce seeds and seeds with 2–3, 5–6% WC were stored at +4°C, over all storage durations. Generally, black spruce and lodgepole pine exhibited high germination at all storage temperatures at 2–3% and 5–6% WC as well as the control (untreated) seed, for up to 60 months in storage. Germination declined for all three species when seed was conditioned to 22–25% WC. This loss in germination was partially recovered in white spruce seed stored at +4, −20 and −80°C after storage durations of 24, 12 and 48 months, respectively, and in black spruce seeds stored at −20 and −196°C after storage durations of 24 months. Mean germination time (MGT) was relatively constant for all species, under all conditions, except for seed conditioned to 22–25% WC, where MGT increased for white spruce seed stored 48 months at −80 and −196°C, and for black spruce seed stored 24 months at +4 and −80°C and 60 months at −196°C. These results show that the optimal storage temperatures are 4°C for white spruce, and 4, −20, −80, and −196°C for black spruce and lodgepole pine, and 2–6% water content is optimal for all 3 species at these temperatures.     

栓皮栎种子及苗期种源变异分析

收集了栓皮栎主要分布区12个种源的种子,对种子及播种苗进行了测定分析.结果表明,栓皮栎种子的大小、质量、发芽率及苗期的生长,在种源间均存在显著差异.栓皮栎中心分布区域种源的种子相对较大,发芽率较高,来自这些区域的种源苗期生长亦较旺盛.苗期生长的显著差异表明,栓皮栎种源间及种源内优良类型选育具有很大潜力.     

NaCl胁迫对榉树种子萌发及幼苗生理指标的影响

研究了0.1%、0.2%、0.4%、0.6%和0.8%NaCl浓度处理对榉树种子萌发和幼苗生理指标的影响.结果显示:榉树种子的发芽率,发芽指数和活力指数在较低NaCl浓度(0.1%)处理下即有显著降低;萌发后幼苗的苗高、根长在较低NaCl浓度(≤0.2%)处理下变化不显著,当NaCl浓度达到0.4%及更高对幼苗的苗高和根长显著减小;幼苗SOD、POD活性随NaCl处理浓度的增加呈先升后降的单峰曲线,MDA含量变化不明显.由此推断,榉树在种子萌发阶段对NaCl胁迫较为敏感,但萌发后的幼苗在较低NaCl浓度(0.2%)下可通过增加保护酶的活性来减少NaCl胁迫产生的危害,从而得以正常生长.     

陆地棉异质型ACCase基因的种子特异表达载体构建与遗传转化

异质型ACCase催化乙酞CoA形成丙二酞辅酶A是植物脂肪酸合成途径中的第一个关键的步骤,也是限速步骤:植物体内过量表达ACCase能够增加脂肪酸合成的底物,有可能导致植株种子含油量的增加.本实验采用GUS基因瞬时表达检测棉花愈伤组织中种子特异性表达启动子AGP的活性;利用RT-PCR扩增,克隆了陆地棉异质型ACCas...     

不同药剂处理对陈年西瓜种子萌发的影响

试验以陈年的西瓜种子为试材,采用不同浓度的生长调节剂和化学试剂进行浸种处理,研究它们对西瓜种子萌发的影响。试验结果表明:不同处理均可显著提高陈年西瓜种子活力,其中以0.1mol/L的SA和3.0%的KNO3处理效果最好。