Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education, Jilin Songnen Grassland Ecosystem National Observation and Research Station, Northeast Normal University, Changchun, 130024, China.
Meteorological Observatory of Jilin Province, Changchun Jilin Province, 130062, China.
Plant Biol (Stuttg). 2021 Sep;23(5):760-769. doi: 10.1111/plb.13278. Epub 2021 Jun 4.
Rainfall use efficiency (RUE) is crucial for understanding the changes in grassland productivity due to variations in future rainfall patterns. Recently, numerous studies have been conducted on the relationship between RUE and the amount of rainfall, but there has been little research on the influence of rainfall distribution and the interactive effect of rainfall amounts and distribution on RUE. Here, a simulated rainfall experiment was conducted to evaluate the impacts of rainfall amount (average rainfall amount (R0), 334 mm; decreased (R-) and increased (R+) rainfall amounts, 233 mm and 434 mm, respectively) and dry intervals (comprising 6-day, 9-day, 12-day, 15-day, 18-day and 21-day intervals between rainfall) on productivity and RUE in Leymus chinensis (Trin.) Tzvel., a dominant grass of the Eastern Eurasian Steppe. Our results showed that (1) for biomass production and RUE, moderate extension of dry intervals was conducive to enhancing total biomass production and RUE. The peak values of total biomass and RUE appeared during the 15-day interval for R-, and the 18-day interval for R0 and R+. (2) For biomass allocation, extension of dry intervals decreased the stem to leaf ratio (S/L) and the root to shoot ratio (R/S). (3) Further, the S/L ratio was significantly negatively correlated with RUE. These results suggest that variations in rainfall patterns can alter the RUE by changing the S/L ratio, and finally influence biomass production in L. chinensis. These findings have important implications for understanding and predicting the effect of future climate change on productivity in semi-arid grassland.
降雨利用效率（RUE）对于理解由于未来降雨模式变化引起的草原生产力变化至关重要。最近，许多研究都集中在 RUE 与降雨量之间的关系上，但对降雨分布的影响以及降雨量和分布对 RUE 的交互作用的研究却很少。在这里，进行了模拟降雨实验，以评估降雨量（平均降雨量（R0），334 毫米；减少（R-）和增加（R+）降雨量，分别为 233 毫米和 434 毫米）和干燥间隔（包括 6 天、9 天、12 天、15 天、18 天和 21 天的降雨间隔）对羊草（Leymus chinensis (Trin.) Tzvel.）生产力和 RUE 的影响，羊草是欧亚大陆东部草原的优势草种。我们的结果表明：（1）对于生物量生产和 RUE，适度延长干燥间隔有利于提高总生物量生产和 RUE。R-的总生物量和 RUE 的峰值出现在 15 天的间隔内，R0 和 R+的总生物量和 RUE 的峰值出现在 18 天的间隔内。（2）对于生物量分配，延长干燥间隔会降低茎与叶的比例（S/L）和根与枝的比例（R/S）。（3）进一步，S/L 比与 RUE 呈显著负相关。这些结果表明，降雨模式的变化可以通过改变 S/L 比来改变 RUE，最终影响羊草的生物量生产。这些发现对于理解和预测未来气候变化对半干旱草原生产力的影响具有重要意义。
