林木种子发芽率的软X射线检验研究

本文应用Hy—35型软X—射线仪对杉木、柳杉等15个树种种子进行摄影并进行定位发芽试验。根据各树种种子的X光片成像特征将种子划分为若干等级,将X光片上判读的百分率与定位发芽所得的发芽率进行统计分析,找出估测各树种种子发芽率的X光片判读等级。     

樟子松种子浸种与不浸种发芽率试验

樟子松又名蒙古赤松、海拉尔松,是我国东北、内蒙古地区的主要森林组成针叶树种,强阳性速生,适应性很强,是绿化、防风固沙的优良树种。一、试验目的根据国家种子检验标准规定,樟子松种子的浸种发芽试验要求用45℃的水浸种24小时,在试验室进行发芽率检验。为简化发芽试验操作步骤,摸清樟子松浸种与不浸种的种子发芽率、发芽势的关系,在种子质量检     

缅茄繁育技术的研究

缅茄是多年前从缅甸引入的一个珍稀外来树种。对缅茄进行种子发芽试验和利用培育出的种子苗进行换冠嫁接研究,发现种子发芽率与种子处理方法关系密切,种子在100℃开水浸种,自然冷却24h取出播种,发芽率可达97%以上;利用嫁接换冠技术,取优良缅茄品种的结果枝作接穗,在秋季进行嫁接,取得较佳效果。     

楠木种子处理办法初探

由于楠木种质资源有限,如何充分利用现有的种质资源进行珍稀树种扩繁,是本次试验的主要目的。在恒温条件下(24℃),利用不同浓度的赤霉素溶液处理经过不同层积天数的楠木种子,然后进行发芽试验。结果表明:900 mg/L的赤霉素溶液浸泡层积时间为50 d的种子,其发芽率最高达到92%,与对照相比差异很大,因此适宜的楠木种子处理方法可以显著提高其发芽率。     

珍稀树种银鹊树种子发芽条件的研究

在南京对银鹊树种子进行了不同种源、不同播种期、不同储藏方法及不同播前处理等发芽试验。结果表明：(1)银鹊树在3月上旬至中旬为其适宜的播种期；(2)水藏的种子发芽率高达95．2％，干藏的种子发芽率为10％左右。如能在播种前采取水浸处理，可适当提高发芽率和缩短发芽时间；(3)种源不同，发芽率也略有差异，湖南张家界种源发芽率最高，江西宜春种源较差。     

杜仲种子发芽试验分析

杜仲为我国特有的经济树种和名贵中药，其皮为重要的中药材。采用传统的种子育苗法其发芽率一般不超过50％。将杜仲种子剥去果皮或剥去果皮并弃去胚根端部分胚乳，接种于Ms＋0．8％琼脂的培养基上进行发芽试验，种子发芽率分别为50％和94％。将种子分别置于10℃、15℃、20℃、25℃、30℃的温度下培养发现，杜仲的最适发芽温度为20℃。     

油松种子山场发芽率试验

<正> 林木种子的山场发芽率是飞播造林确定播种量的重要依据。为了摸索油松种子山场发芽率与种子品质的关系,我们将相同的种子样品分别进行了室内种子质量检验和山场发芽试验。     

金链树种子发芽特性及幼苗生长规律研究

对引自欧洲的金链树种子进行种子发芽试验以及苗期生长量观测。结果表明:热水浸种、低温沙藏及浓硫酸处理对金链树种子发芽率差异极显著(P0.01)。金链树种子热水浸种和沙藏均能促进种子提前发芽,先用60℃热水浸泡24 h,再低温4℃沙藏72 h的处理发芽率最高,达77.33%;浓硫酸处理对种子伤害较大,发芽率仅为14.67%。金链树全年苗高、地径生长进程呈现"慢-快-慢"的生长趋势。高生长以6月份最快,增长量达28.11 cm,占全年高增长的20.76%;地径生长5月份最快,增长2.36 mm,为全年地径增长的24.23%。相关分析表明,影响金链树苗期生长的环境因子主要为水分条件。     

不同处理方法对樟树种子发芽的影响

对樟树(Cinnamomum camphora)种子采取不同激素和不同贮藏方法进行发芽试验,分析其种子发芽率及发芽势。结果表明:不同激素处理后,种子发芽势和发芽率差异显著,浓度100 mg/L NAA处理后的种子发芽势和发芽率最高;经不同贮藏处理后,种子发芽势和发芽率也差异显著,沙藏保湿处理的发芽势和发芽率明显高于其它处理。     

缅茄种子发芽试验研究

对缅茄进行种子发芽试验,结果表明种子在100℃沸水浸种,自然冷却24 h取出播种,发芽率可达97％以上。试验结果还显示,用温度低的水浸种处理,种子发芽率不理想,而用机械损伤处理种子,浸种时间过长,发芽率亦不理想。     

湿地松等20个树种种子射线造影技术研究

应用软Ｘ射线仪对湿地松等２０个树种种子进行衬比造影和直接造影技术研究，找出了各树种种子不同焦片片距（３００ｍｍ和２００ｍｍ）不同感光材料（Ｘ光胶片、普通胶片、相纸）的最适电压、电流和曝光时间，以及最适衬比剂、衬比浓度和衬比时间．     

楠属种子萌发过程中过氧化物酶活力研究

种子的发芽力是判断种子质量的重要指标。本文通过对楠木属中桢楠、细叶楠及浙江楠等3树种的种子萌发过程中过氧化物酶活力所作的研究表明：过氧化物酶活力与种子发芽力存在着紧密的相关关系．它可作为确定种子活力的重要依据。     

木荷种子贮藏方法试验初报

对木荷种子进行低温冷藏和常温贮藏试验。结果表明：低温冷藏7个月、常温贮藏8个月的种子发芽率分别为20．8％和3．8％，t检验结果为两种处理的木荷种子发芽率差异极显著。说明不同的贮藏方法对木荷种子的发芽有显著的影响。     

Seed bank analysis of tree species in two stands of the Tenerife laurel forest (Canary Islands)

We analyzed the germination from the seed bank for two laurel forest stands (Moquinal versus Aguirre) of Tenerife collected at two different seasons (summer versus winter). We incubated and monitored germination in greenhouse conditions for 1 year. A high variability in germination was found between trays. Germination was much higher in summer than in winter, especially from Moquinal seed bank. Shade tolerant species (Laurus azorica, Persea indica, Rhamnus glandulosa and Viburnum tinus) have a shorter germination delay than shade-intolerant species (Erica arborea, Erica scoparia and Myrica faya), which dominate the seed bank. The species composition of germinating seeds after one year did not reveal any differences between sites nor between, despite the high differences in number between seasons.

We compared the species composition of germinating seeds to that of the canopy (expressed as basal area). The results indicate that the winter seed bank does not significantly differ from the canopy composition in the Aguirre stand. We interpret our results to imply that the Aguirre stand is of an earlier successional stage than the Moquinal stand, because of a higher species richness in the germinated tree seeds, and compositional similarities between the winter seed bank and the canopy (both characteristic of earlier successional stages).     

Effects of litter from a tropical rainforest on tree seed germination and establishment under controlled conditions

The effects of litter cover on the germination of seeds of three tropical rainforest, pioneer tree species (Cecropia obtusifolia, Heliocarpus appendiculatus and Piper auritum) was investigated. Germination of seeds of all tree species was partially or totally inhibited when the seeds were covered with litter, whereas uncovered seeds or seeds covered with paper instead of litter germinated. Seed size was directly correlated with the capacity of the germinated seeds to emerge through the litter. In soil experiments in the greenhouse, seedling emergence from the soil was inhibited by the presence of litter on the soil surface.     

聚乙二醇模拟干旱对三种木麻黄种子萌发的影响

为研究木麻黄Casuarinaceae.种子苗困难地造林,以木麻黄为试验材料,用不同渗透势浓度的聚乙二醇(PEG-6000)模拟干旱胁迫,探讨干旱胁迫对木麻黄种子发芽率、发芽势、胚轴和胚根长度及发芽指数、活力指数的影响。结果表明,不同浓度PEG胁迫处理均降低了种子的发芽率,延缓了木麻黄种子萌发进程;种子的发芽率、发芽指数和活力指数均随胁迫强度的增加呈明显下降趋势。当-1.20 MPa的PEG胁迫处理的种子在试验结束时仍未能萌发,表明-1.20 MPa是木麻黄种子萌发的临界水势。当PEG浓度为150 g/L时,三种木麻黄幼苗的胚根最长,且当PEG浓度为100 g/L时,三种木麻黄胚根长度长于对照组,但差异不显著,说明高于-0.40 MPa的水势有利于木麻黄种子胚根的生长。木麻黄幼苗苗高生长则是随着PEG浓度的升高而逐渐减缓。通过比较得知木麻黄种子抗旱性较强。     

Consequences of dry-season seed dispersal on seedling establishment of dry forest trees: Should we store seeds until the rains?

We examined the following hypotheses: (i) seeds of dry forest trees have high pre- and post-germination mortality by desiccation due to the time between seed dispersal and germination and to irregular rains at the onset of the rainy season; (ii) seedlings from seeds dispersed in the dry season which survive the dry spells are larger at the end of the first rainy season than those dispersed in the rainy season because the former have more time to grow. We evaluated the possible trade-off between few large seedlings (resulting from natural dispersal) × many small seedlings (resulting from delayed dispersal) on seedling survival during the dry season. We sowed eight tree species in a greenhouse in September, simulating the natural dispersal timing (before the rains), and in November, when rains are more constant. Because shading can counteract the effects of desiccation, we applied three levels of shade (10%, 40% and 72% of PPFD). From September 2005 to December 2006, we provided the daily precipitation of a median year from a major patch of dry forest in Central Brazil. At the end of the rainy season, a subset of seedlings was collected for growth measurements (dry mass) and the remainder was left to follow the dry season survivorship. The lower germination expected for seeds dispersed in the dry season and in full sun was not confirmed for species that had some dormancy. The delayed dispersal was advantageous for the initial establishment of fast germinating species, but it was irrelevant or even disadvantageous for others. Also, the greenhouse weather was certainly milder than the natural environment, reducing the potential for mortality by desiccation. The growth of the four species of higher dormancy were not affected by timing of seed dispersal, while three out of four fast germinating species had higher root biomass when dispersed in the dry season. The growth during the rainy season did not affect seedling survival during the dry season. Keeping seeds to sow when rain is constant might be a good strategy to increase the establishment of fast-germinating tree species.     

高山红景天种子散布模式与种子发芽试验

1997年调查了长白山地区(Rhodiola sachalinensis)种子散布,发现高山红景天种子散布方向是不均匀的,以东部和西部最多。发芽试验的种子采自吉林省长白山和黑龙江省大海林迁地保护基地。种子采集后立刻用2%KNO3处理10小时、0.02%GA3处理5小时,结果显示迁地保护基地的高山红景天种子萌发率(85.33%)明显高于长白山(72.66%)。在0～5℃下贮存10个月之后,经上述不同浓度的激素处理,再测定发芽率。结果表明其发芽率为与刚采收时的发芽率(72.66%)差别不大,说明低温处理可明显延长种子寿命,同时发现,种子发芽率在一定程度上随激素浓度的增加而提高。图参9。     

Structure and composition of the seed bank in monospecific and tree species-rich temperate broad-leaved forests

How tree species diversity affects ecosystem functioning is a topic of intensive research. This study compares monospecific and species-rich broad-leaved forests under similar bedrock and climate conditions for the size and composition of their seed bank. We tested the hypotheses that (i) the actual herb-layer vegetation has an only weak influence on the composition of the seed bank, (ii) the species diversity of the seed bank increases with tree-layer diversity, and (iii) tree species forming a more persistent litter layer reduce the number of germinating seeds. The number of seeds and their species composition were investigated in soil cores taken from three soil depths (0–5, 5–10 and 10–20 cm; n = 4, with each 6 sub-samples) in 9 study plots differing in tree species diversity (3 monospecific Fagus plots, 3 plots with Fagus, Fraxinus and Tilia, and 3 plots with Fagus, Fraxinus, Tilia, Carpinus and Acer). Tree species diversity had a much stronger influence on the size and composition of the seed bank than herb-layer diversity or composition, the latter revealing only a low similarity to the corresponding seed bank. The number and species diversity of emerging seedlings decreased significantly with the amount of acidifying Fagus litter, but increased with litter mass of Tilia and other trees with nutrient-rich, rapidly decomposing litter. We conclude that tree species diversity does not influence the seed bank through effects on herb-layer composition, but mostly through differential disturbance histories of the stands and litter quality effects on germination and soil chemistry. From the contrasting effects of Fagus and Tilia leaf litter, it appears that effects of tree species identity are more relevant than influences of tree species diversity itself.     

马尾松、糖槭种子成分分析和利用

分析了马尾松 (PinusmassonianaL .)和糖槭 (AcernegundoL .)种子的化学成分。试验结果表明 :(1)不同树种及同一树种不同部位的化学成分含量不同 ;(2 )马尾松种子贮藏物质以脂肪为主 ,蛋白质次之 ;(3)糖槭种子以蛋白质为主 ,脂肪次之 ;(4 ) 2树种油脂中均以不饱和脂肪酸 (油酸、亚油酸 )为主 ;蛋白质组成主要以谷氨酸、精氨酸、天门冬氨酸、亮氨酸为主 ;(5) 2树种种子中含有丰富的VE,并有一定的营养价值