三江平原小叶樟和毛果苔草中N素营养动态分析

讨论了沼泽湿地优势种小叶樟（Ｃａｌａｍａｇｒｏｓｔｉｓ ａｎｇｕｓｔｉｆｏｌｉａ）和毛果苔草（Ｃａｒｅｘ ｌａｓｉｏｃａｒｐａ）生物量和生长率变化情况，不同生长期各器官中Ｎ素含量及储量动态变化，以及植物对Ｎ素利用和区域养分限制情况。结果表明，两种植物地上生物量生长符合模式ｐ＝γ＋ａｔ＋βｔ＾２，地下生物量符合曲线ｐ＋ａ０＋ｂ０ｔ；受土壤水分、养分、气温和植物本身特点及其对Ｎ素选择吸收作用等多种因素

Nitrogen dynamics in different organs of Calamagrostis angustifolia and Carex lasiocarpa in Sanjiang plain

The dynamics of nitrogen content and storage in different organs of Calamagrostis angustifolia and Carex lasiocarpa which are dominant vegetation in swamp wetland were determined, and the utilization rate of nitrogen and its nutrient limitation in the region were analyzed. The results showed that the aboveground and underground biomass might be described by p = gamma + alpha t + beta t2 and p = a0 + b0t, respectively. The content of total N, NH4(+)-N and NO3(-)-N varied widely with different organs because of the effects of soil water, nutrient content, atmospheric temperature, vegetable feature and selective absorption to nitrogen, etc. The content of NO3(-)-N in different organs varied less than that of NH4(+)-N, and NH4(+)-N/NO3(-)-N was < 1. The N:P content less than 14 in two vegetations showed that it was N but not P was the limitation nutrient to the growth of vegetation in this region, moreover, the limitation was less in July than in August. This conclusion was also drawn from the analysis of the NH4(+)-N and NO3(-)-N content in soil.