不同载畜率下短花针茅分蘖数量对内源激素浓度的响应

放牧是荒漠草原最主要的利用方式之一,载畜率的变化严重影响着植物的生长发育;而内源植物激素是调节植物生长发育的开关,且植物在不同的生长发育阶段具有不同的生理要求和环境适应能力。通过测定放牧条件下短花针茅(Stipa breviflora)分蘖叶内源激素的变化,研究短花针茅分蘖生长对放牧的响应,并分析了分蘖数量受内源激素影响的机制。结果表明,(1)内源激素与载畜率之间存在显著二次相关关系,说明放牧能够显著增加内源激素的浓度(P0.05),但这种相关只存在于中、小株丛的短花针茅中。(2)其次,放牧能够在一定程度上影响短花针茅植株个体分蘖的数量(P0.05),重度放牧是增加短花针茅植株个体分蘖数量最显著的载畜率。(3)过高浓度的生长素(IAA)会抑制短花针茅的分蘖数量(P0.01)。而细胞分裂素(CTK)与短花针茅的分蘖数量之间尚未发现相关关系。

Response in tiller numbers of Stipa breviflora to endogenous hormone concentration under different stocking rates

Grazing is one of the most important uses of desert grassland. Changes in livestock rates seriously affect the growth and development of plants. Endogenous plant hormones are the switches that regulate plant growth and development, and plants exhibit different physiologies at different stages of growth and development. In this study, the changes in endogenous hormones in the leaves of Stipa breviflora under different grazing conditions were studied to determine the response of Stipa breviflora to grazing, and the mechanism by which the number of tillers was affected by endogenous hormones were analyzed. The results showed that:(1) there was a significant quadratic correlation between endogenous hormones and stocking rates, suggesting that grazing significantly increased the concentration of endogenous hormones (P < 0.05), but this correlation existed only for medium and small strains of Stipa breviflora. (2) Grazing could affect the number of individual tillers of Stipa breviflora to a certain extent (P < 0.05), and heavy grazing had the most significant impact on the rate of individual tillers in Stipa breviflora. (3) The over-concentration of auxins (IAA) inhibited the number of tillers in Stipa breviflora (P < 0.01). However, no correlation was found between cytokinin (CTK) and the number of tillers of Stipa breviflora.