Plasticity and evolution in drought avoidance and escape in the annual plant Brassica rapa
Plasticity and evolution in drought avoidance and escape in the annual plant Brassica rapa
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DOI：
10.1111/j.1469-8137.2010.03603.x
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发表时间：
2011-01-01
期刊：
影响因子：
9.4
通讯作者：
Franks, Steven J.
中科院分区：
文献类型：
--
作者：
Franks, Steven J.
生态遗传学中的一个关键问题是植物在多大程度上通过可塑性或进化来适应气候条件的变化，如干旱。为了解决这个问题，我们从自然干旱之前（1997年）和之后（2004年）收集的140个芜菁母系家族的种子中产生了种子。这些种子被种植在温室中，在低水和高水条件下生长，干旱后的品系比干旱前的品系开花早，显示出开花早的进化转变。开花时间存在显著的遗传变异和基因型与环境互作，表明该性状存在遗传变异的可塑性。开花早的植株比开花晚的植株具有较少的叶节和较低的瞬时（A/g）和综合（Δ 13 C）水分利用效率。芜菁植物通过提早开花来躲避干旱，而不是通过提高水的利用效率来避免干旱。这种反应的机制似乎是高蒸腾和水的利用效率低，导致快速发展。这些研究结果表明干旱回避和逃逸之间的权衡，并表明，在这个系统中，干旱的行为，以缩短生长季节，选择干旱逃逸通过早期开花比表型可塑性更重要。
P>A key question in ecological genetics is to what extent do plants adapt to changes in climatic conditions, such as drought, through plasticity or evolution.To address this question, seeds of 140 maternal families of Brassica rapa were generated from collections made before (1997) and after (2004) a natural drought. These seeds were planted in the glasshouse and grown under low-water and high-water conditions.Post-drought lines flowered earlier than pre-drought lines, showing an evolutionary shift to earlier flowering. There was significant genetic variation and genotype by environment (G x E) interactions in flowering time, indicating genetic variation in plasticity in this trait. Plants that flowered earlier had fewer leaf nodes and lower instantaneous (A/g) and integrated (delta 13C) water use efficiency than late-flowering plants.These results suggest that B. rapa plants escape drought through early flowering rather than avoid drought through increased water use efficiency. The mechanism of this response appears to be high transpiration and inefficient water use, leading to rapid development. These findings demonstrate a trade-off between drought avoidance and escape, and indicate that, in this system, where drought acts to shorten the growing season, selection for drought escape through earlier flowering is more important than phenotypic plasticity.