降水增加对古尔班通古特沙漠两种短命植物生长的影响

短命植物是荒漠生态系统中的重要组成部分,发挥着重要的生态功能,对其不同生长阶段形态特征及生物量积累与分配进行研究,有助于深入了解荒漠短命植物的功能特征及生存策略。本研究选取古尔班通古特沙漠2种短命植物——毛穗旱麦草和小花荆芥为对象,通过野外增水30%、50%,分析降水增加对二者不同生长阶段形态、生物量特征的影响。结果表明: 增水30%、50%均促进毛穗旱麦草植株生长,增水处理下叶面积增幅为14.2%～188.5%,繁殖器官生物量最大增幅为55.9%。增水对小花荆芥植株影响存在生长阶段的差异性,展叶期增水对小花荆芥植株生长均有促进作用,而果熟期增水50%小花荆芥叶面积、株高、繁殖器官生物量分别降低54.9%、20.5%、43.2%。两种短命植物对降水增加的响应具有物种特异性,未来降水增加可能会改变二者生存策略,进而对群落组成与结构产生影响。

Effects of increased precipitation on growth of two ephemeral plants in the Gurbantunggut Desert,China

Ephemeral plants are a major component of biodiversity in the deserts of Northwest China, with important ecological functions. Information on plant morphological characteristics and biomass accumulation and allocation during different growth stages could enhance our understanding of the functional features and survival strategy of ephemeral plants. We examined the effects of increased precipitation on ephemeral species Eremopyrum distans and Nepeta micrantha in the Gurbantunggut Desert. Changes in morphological characteristics and biomass accumulation and allocation were analyzed under increasing precipitation 30% and 50% treatments. The results showed that increased precipitation 30% and 50% treatments promoted the growth of E. distans, with leaf area and reproductive organ biomass being increased by 14.2%-188.5% and 55.9%, respectively. The effects of increased precipitation on the growth of N. micrantha varied across different growth stages. At leaf expansion stage, increased precipitation promoted growth of N. micrantha, while at fruit ripening stage, increased precipitation 50% treatment reduced leaf area, plant height, and reproduction biomass by 54.9%, 20.5%, 43.2%, respectively. Thus, the responses of the two species to increased precipitation was species-specific. Increased precipitation would change the survival strategies of the two species, with consequence on the species composition and structure of desert community.