天然赤松个体生物量的研究

对延边地区不同密度天然赤松林中不同生长势的赤松个体地上部生物量进行了研究.结果表明,不同生长势赤松生物量变化受密度影响的顺序为:优势木<平均木<被压木;各器官生物量分配比例受密度影响的顺序为:干>枝>叶>皮.不同生长势赤松的生物量结构在林分密度达到Ⅲ级时发生显著变化,其中平均木的变化与林分基本相同.不同生长势赤松的生物量垂直分布虽然各具特点,但都表现为:树干和树皮生物量主要分布在6m树高范围内,树枝则集中在6～10m范围,针叶在上、中、下3层林冠中均分,上层林冠的枝叶量受密度影响最小.

Studies on Regulating Effects of Ecological Factors on the Yield- related traits in Maize

Regulating effects of ecological factors such as planting density,fertilizer,water and photointensity on the yield-related traits in Maize were studied by the methods of combination of field-growth with pot-growth. The results are as follows:raising density can cause the decrease of chlorophyll content, leaf area and dry weight per plant. The effects of density and the interaction of density with fertilizer on the grain number per ear reached high significant levels(F=55 08 ** ,F=70 30 ** ). The effect of P fertilizer is less than that of density(F=7 33 *). Grain weight and grain number per ear was reduced 44 66% and 52 32% under drought from silking to 6 days after silking respectivily. Abortive grains were increased 443 85% and 100-grain weight was decreased 21 81% from 12 to 17 days after silking.Photointensity on ear position and low leaf layer were correlated and regressed significantly to grain traits.