Elberse W Th, Breman H
Centre for Agrobiological Research (CABO), P.O. Box 14, NL-6700 AA, Wageningen, The Netherlands.
Oecologia. 1990 Nov;85(1):32-40. doi: 10.1007/BF00317340.
In order to understand the vegetation dynamics of Sahelian rangelands, the effects of water availability on germination were investigated under controlled conditions in climate rooms. Mixtures of seeds from species that occur in the same habitats but have different seed characteristics were exposed to different watering treatments. Responses to the treatments in the climate room were comparable to those observed in the field situation. However, induction time was generally some-what longer, and in some cases the germination rate was lower. The size, frequency, and timing of showers decisively influenced the ratio between the proportions of the various species among the seedlings that established. In general, conditions were favourable for fast germinating species with rainfall patterns without serious intermittent periods of drought, whereas the conditions became favourable for the slower germinating species after dry periods had eliminated the seedlings of the fast germinating species. Large differences in drought resistance were found among seedlings of different species. This causes more differentiation in establishment of species. Seed losses during the pre-emergence phase were also important. These losses can be very high, especially for the fastest germinating species. The dynamics observed in field situations could be explained on the basis of germination characteristics and drought resistance.
为了解萨赫勒地区牧场的植被动态，在气候室的可控条件下研究了水分可利用性对种子萌发的影响。将来自同一栖息地但具有不同种子特征的物种的种子混合物进行不同的浇水处理。气候室中对处理的反应与田间情况中观察到的反应相当。然而，诱导时间通常稍长一些，在某些情况下发芽率较低。阵雨的大小、频率和时间决定性地影响了已建立的幼苗中不同物种比例之间的比率。一般来说，对于没有严重干旱间歇期的降雨模式，条件有利于快速发芽的物种，而在干旱期消除了快速发芽物种的幼苗后，条件对发芽较慢的物种变得有利。不同物种的幼苗在抗旱性方面存在很大差异。这导致物种建立过程中更多的分化。出土前阶段的种子损失也很重要。这些损失可能非常高，尤其是对于发芽最快的物种。基于发芽特性和抗旱性可以解释在田间情况中观察到的动态。
