荒漠短命植物地上和地下生产力对极端干旱和降水的响应

在古尔班通古特沙漠南缘沙垄4个坡位和坡向,设置减少65%和增加65%生长季降水量以模拟极端干旱和极端降水事件,研究极端干旱和极端降水事件对沙垄不同坡位和坡向短命植物层片生产力的影响。结果表明: 极端干旱使地上净初级生产力和地下净初级生产力分别显著降低48.8%和13.7%,极端降水使地上净初级生产力和地下净初级生产力分别显著增加37.9%和23.2%。地上净初级生产力对极端干旱和极端降水的敏感性(0.26和0.21 g·m^-2·mm^-1)显著强于地下净初级生产力的敏感性(0.02和0.03 g·m^-2·mm^-1)。沙垄东坡地上净初级生产力(24.22 g·m^-2)和地下净初级生产力(5.77 g·m^-2)与西坡相比显著增大29.7%和71.7%,而地上净初级生产力和地下净初级生产力对降水变化的敏感性在不同坡位和坡向之间差异不显著。

Responses of aboveground and belowground net primary productivity of ephemeral plants to extreme drought and extreme precipitation

To examine the effects of extreme drought event and extreme precipitation event on productivity of ephemeral plant, we experimentally reduced and increased growing season precipitation amounts by 65% across four slope positions and aspects along sand dunes in the southern edge of the Gurbantünggüt Desert. The results showed that extreme drought significantly reduced aboveground net primary productivity (ANPP) and belowground net primary productivity (BNPP) by 48.8% and 13.7%, respectively, and that extreme precipitation significantly increased ANPP and BNPP by 37.9% and 23.2%, respectively. The sensitivity of ANPP (0.26 and 0.21 g·m^-2·mm^-1) to extreme drought and extreme precipitation was significantly higher than that of BNPP (0.02 and 0.03 g·m^-2·mm^-1). In addition, ANPP (24.22 g·m^-2) and BNPP (5.77 g·m^-2) on the east side of sand dune were significantly increased by 29.7% and 71.7% compared with those on the west side. There was no significant difference in the sensitivity of ANPP and BNPP to precipitation change among different slope positions and aspects.