Yi Fengyan, Wang Zhaoren, Baskin Carol C, Baskin Jerry M, Ye Ruhan, Sun Hailian, Zhang Yuanyuan, Ye Xuehua, Liu Guofang, Yang Xuejun, Huang Zhenying
Inner Mongolia Research Center for Prataculture, State Key Laboratory of Vegetation and Environmental Change, Institute of Botany Chinese Academy of Sciences Beijing China.
Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences Hohhot China.
Ecol Evol. 2019 Jan 25;9(4):2149-2159. doi: 10.1002/ece3.4909. eCollection 2019 Feb.
Investigating how seed germination of multiple species in an ecosystem responds to environmental conditions is crucial for understanding the mechanisms for community structure and biodiversity maintenance. However, knowledge of seed germination response of species to environmental conditions is still scarce at the community level. We hypothesized that responses of seed germination to environmental conditions differ among species at the community level, and that germination response is not correlated with seed size. To test this hypothesis, we determined the response of seed germination of 20 common species in the Siziwang Desert Steppe, China, to seasonal temperature regimes (representing April, May, June, and July) and drought stress (0, -0.003, -0.027, -0.155, and -0.87 MPa). Seed germination percentage increased with increasing temperature regime, but , , , , , and germinated to >60% in the lowest temperature regime (April). Germination decreased with increasing water stress, but , , , , , and germinated to near 60% at -0.87 MPa. Among these eight species, germination of six was tolerant to both temperature and water stress. Mean germination percentage in the four temperature regimes and the five water potentials was not significantly correlated with seed mass or seed area, which were highly correlated. Our results suggest that the species-specific germination responses to environmental conditions are important in structuring the desert steppe community and have implications for predicting community structure under climate change. Thus, the predicted warmer and dryer climate will favor germination of drought-tolerant species, resulting in altered proportions of germinants of different species and subsequently change in community composition of the desert steppe.
研究生态系统中多个物种的种子萌发如何响应环境条件，对于理解群落结构和生物多样性维持机制至关重要。然而，在群落水平上，关于物种种子萌发对环境条件的响应的知识仍然匮乏。我们假设在群落水平上，种子萌发对环境条件的响应因物种而异，且萌发响应与种子大小无关。为了验证这一假设，我们测定了中国四子王沙漠草原20个常见物种的种子萌发对季节性温度变化（代表4月、5月、6月和7月）和干旱胁迫（0、-0.003、-0.027、-0.155和-0.87 MPa）的响应。种子萌发率随温度升高而增加，但 、 、 、 、 、 和 在最低温度条件下（4月）萌发率超过60%。萌发率随水分胁迫加剧而降低，但 、 、 、 、 、 和 在-0.87 MPa时萌发率接近60%。在这八个物种中，有六个物种的萌发对温度和水分胁迫均具有耐受性。四个温度条件和五个水势下的平均萌发率与种子质量或种子面积均无显著相关性，而种子质量和种子面积高度相关。我们的结果表明，物种特异性的萌发对环境条件的响应在构建沙漠草原群落中很重要，并且对预测气候变化下的群落结构具有启示意义。因此，预计气候变暖和变干将有利于耐旱物种的萌发，导致不同物种萌发个体比例发生变化，进而改变沙漠草原的群落组成。
