封育对伊犁绢蒿种群营养元素分配格局及贮量的影响

以绢蒿(Seriphidium)荒漠草地上的伊犁绢蒿(S.transiliense)为研究对象，从不同构件的生物量、碳（C）与营养元素含量、贮量及分配格局入手，研究围栏封育对其资源分配格局和生态策略的影响。结果表明，在围栏封育3～4年时，伊犁绢蒿根中磷(P)含量和根颈、生殖枝中氮(N)含量以及根颈、营养枝中钙(Ca)含量均显著增加(P<0.05)。除Ca、镁(Mg)外，其他营养元素贮量在围栏封育后显著增加(P<0.05)；随着退化梯度的减轻，生殖枝、营养枝生物量与C贮量均呈增加趋势，围栏封育使其进一步增加。围栏封育后，生殖枝的N、钾(K)分配比例与营养枝Ca、Mg、C的分配比例均增加，根颈的N/C增加，生殖枝的N/C则显著增加(P<0.05)。上述结果表明，围栏封育后绢蒿荒漠草地土壤供给营养元素的能力增加，伊犁绢蒿在营养生长和生殖生长上的资源投入增加，有利于伊犁绢蒿种群的生态恢复。

Effects of enclosure on storage and allocation of carbon and nutrient elements in Seriphidium transiliense population

The effects of the enclosure on the resource allocation pattern and ecological strategy of Seriphidium transiliense population was investigated. The content, storage and allocation pattern of biomass, carbon and nutrient elements in the sagebrush desert grassland were analyzed on September and October, 2009 and 2010. The results showed that the P content of root, the N content of reproductive shoot, the Ca content of root crown and vegetative shoot in enclosure of moderate degraded plot were significantly higher than those of outside plots (P<0.05). The storage of N, P, K significantly increased after enclosure (P<0.05). The storage of C, the biomass of reproductive shoot and vegetative shoot increased with the decreasing of degraded intensity, and the values increased more in enclosure of moderate degraded plot. The proportion of N, K of reproductive shoot, the proportion of Ca, Mg and C of vegetative shoot, the ratios of N and C of root crown all showed an increasing trend after enclosure. The ratios of N and C of reproductive shoot in enclosure of moderate degraded plot were significantly higher than those of outside plots (P<0.05). The present results suggested that the supply capacity of nutrition of the soil, the resource allocation to vegetative shoot and reproductive shoot all increased in the sagebrush desert grassland after enclosure. The improvement of soil and these performances of S.transiliense population were beneficial to its ecological restoration.