Polyploidy affects the seed, dormancy and seedling characteristics of a perennial grass, conferring an advantage in stressful climates.,Plant Biology

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Polyploidy affects the seed, dormancy and seedling characteristics of a perennial grass, conferring an advantage in stressful climates.
Plant Biology ( IF 4.2 ) Pub Date : 2020-03-10 , DOI: 10.1111/plb.13094
A V Stevens _{1,

2,

3} , A B Nicotra ₁ , R C Godfree ₃ , L K Guja _{2,

3}

Affiliation

Polyploidy (the state of having more than two genome copies) is widely distributed in flowering plants and can vary within species, with polyploid races often associated with broad ecological tolerances. Polyploidy may influence within-species variation in seed development, germination and establishment. We hypothesized that interactions between polyploidy and the seed developmental environment would affect subsequent dormancy, germination and early growth traits, particularly in stressful environments. Using seeds developed in a common garden under ambient and warmed conditions, we conducted germination trials under drought and temperature stress, and monitored the subsequent growth of seedlings. The study species, Themeda triandra, is a widespread, keystone, Australian native grass and a known polyploid complex. Tetraploid plants produced heavier, more viable seeds than diploids. Tetraploids were significantly more dormant than diploids, regardless of seed developmental environment. Non-dormant tetraploids were more sensitive to germination stress compared to non-dormant diploids. Finally, tetraploid seedlings were larger and grew faster than diploids, usually when maternal plants were exposed to developmental temperatures atypical to the source environment. Seed and seedling traits suggest tetraploids are generally better adapted to stressful environments than diploids. Because tetraploid seeds of T. triandra are more dormant they are less likely to germinate under stress, and when they do germinate, seedling growth is rapid and independent of seed developmental environment. These novel results demonstrate that polyploidy, sometimes in interaction with developmental environment and possibly also asexuality, can have within-species variation in seed and seedling traits that increase fitness in stressful environments.

中文翻译：

多倍体会影响多年生草的种子，休眠和幼苗特性，从而在有压力的气候下具有优势。

多倍体（具有两个以上的基因组拷贝的状态）广泛地分布在开花植物中，并且在种内可以变化，多倍体种族通常与广泛的生态耐受性相关。多倍体可能影响种内种子发育，发芽和定植的变异。我们假设多倍体与种子发育环境之间的相互作用会影响随后的休眠，萌发和早期生长性状，特别是在压力环境下。使用在环境和温暖条件下在普通花园中培育的种子，我们在干旱和温度胁迫下进行了发芽试验，并监测了幼苗的后续生长。研究物种Themeda triandra是一种分布广泛的基石，澳大利亚本地草并且是已知的多倍体复合体。四倍体植物产生的种子比二倍体更重，更有活力。无论种子发育环境如何，四倍体的休眠都比二倍体显着多。与非休眠二倍体相比，非休眠四倍体对萌发压力更敏感。最后，四倍体幼苗比二倍体更大并且生长更快，通常是当母本植物暴露于非源环境的发育温度时。种子和幼苗的性状表明，四倍体通常比二倍体更好地适应胁迫环境。由于T. triandra的四倍体种子更休眠，因此它们在压力下发芽的可能性较小，当它们发芽时，幼苗生长迅速且不受种子发育环境的影响。这些新颖的结果表明，多倍性

更新日期：2020-03-10

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