Abstract:

【Objective】 To study the effects of fenced enclosure and free grazing on growth patterns and endogenous hormone levels of Seriphidium transiliense, and to provide theoretical reference for vegetation restoration in degraded Artemisia desert grassland ecosystems. 【Methods】 Fencing and free grazing Seriphidium transiliense were taken as the research objects, and the methods in botany, plant physiology and turf management in the plant morphology, plant endogenous hormones and "four times the amount of" approach to Seriphidium transiliense plant height, coverage, density, biomass, primary branch number and secondary branch number were applied to conduct statistics, The dry weight of leaves, stem and root of each plant were measured by drying method, and the contents of endogenous hormones (IAA, ABA, CTK, GAs and ETH) were measured by targeting method. Three transect lines were set for each treatment, and 40 quadrats were measured by each transect line. Furthermore, the growth rule and endogenous hormone changes of Seriphidium transiliense under the two treatments were summarized.【Results】 The plant height, biomass, leaf dry weight, stem dry weight and root dry weight were 2.57 times, 29.73 times, 7 times, 7.87 times, 5.21 times and 5.64 times, respectively of those fenced in Seriphidium transiliense. Fencing and free grazing had significant effects on CTK and ABA contents in leaves of Seriphidium transiliense (P < 0.05). Except GAs, there was no significant difference in the content of endogenous hormones in stem of Seriphidium transiliense between the two treatments (P< 0.01). Fencing had little effect on endogenous hormones of root system, but the content of ETH was significantly different between them (P< 0.05). 【Conclusion】 Fenced for 4 years, the morphological characteristics and growth trend of Seriphidium transiliense are in sharp contrast with the miniatures and dwarfism of free grazing, especially the IAA and CTK contents of leaves and stems are more closely related to plant height and first-order branch number.

Key words: Seriphidium transiliense; fenced enclosure; free grazing; plant endogenous hormones; growth rule

摘要：

【目的】 研究围栏封育和自由放牧对伊犁绢蒿(Seriphidium transiliense)生长规律和内源激素水平的影响,分析蒿属荒漠草地围栏封育效果,为退化的蒿属荒漠草地生态系统中植被恢复研究提供理论参考依据。【方法】 以围栏封育和自由放牧条件下的伊犁绢蒿为研究对象,利用植物学、植物生理学和草地管理学中有关植物形态、植物内源激素和“四度一量”方法,计数统计伊犁绢蒿高度PH、盖度PC、密度PD、生物量B、一级分枝PBN和二级分枝SBN,采取烘干法测定单株叶片干重、单株茎干重和单株根系干重,采取靶向测定内源激素(细胞分裂素IAA、脱落酸ABA、生长素CTK、赤霉素GAs、乙烯ETH)含量,每处理设置3条样线,每样线测定40个样方,对比分析各项指标,归纳总结伊犁绢蒿在两个处理下的生长规律和内源激素变化。【结果】 围栏封育条件下的伊犁绢蒿株高是自由放牧株高的2.57倍,生物量是自由放牧的29.73倍,一级分枝是自由放牧的7倍,单株叶片干重、茎干重和根系干重分别是自由放牧的7.87倍、5.21倍和5.64倍;围栏封育和自由放牧对伊犁绢蒿叶片CTK和ABA含量影响较大,且差异显著(P<0.05);对伊犁绢蒿茎内源激素含量除了赤霉素(GAs)在2个处理间差异不显著以外,其他指标在两个处理间差异均极显著(P<0.01)。围栏封育对伊犁绢蒿根系内源激素影响较小,仅ETH含量在二者之间差异显著(P<0.05)。【结论】 围栏封育4年,不仅使伊犁绢蒿形态特征、生长趋势与自由放牧的小型化和矮化形成鲜明对比,尤其叶片和茎的IAA和CTK含量与植株高度和一级分枝数之间关系更密切。

关键词: 伊犁绢蒿, 围栏封育, 自由放牧, 内源激素, 生长规律