Sexual dimorphism and sex ratios of two Australian dioecious species of alpine pineapple grass, Astelia alpina var. novaehollandiae and Astelia psychrocharis (Asteliaceae)
Sexual dimorphism and sex ratios of two Australian dioecious species of alpine pineapple grass, Astelia alpina var. novaehollandiae and Astelia psychrocharis (Asteliaceae)
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澳大利亚两种雌雄异株的高山菠萝草 Astelia alpina var. 的性别二态性和性别比例
DOI：
10.1111/j.1756-1051.2003.tb00385.x
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发表时间：
2003
影响因子：
0.9
通讯作者：
W. Hill
中科院分区：
文献类型：
--
作者：
C. Pickering;Marković Jordan;W. Hill
在经历了许多高山环境中发现的有限生长和繁殖条件的雌雄异株植物中，已经预测到性别二型性和男性偏见的性别比。为了验证这些预测，在澳大利亚东南部科斯丘兹科国家公园的亚高山和高山地带对两个同属、共生、雌雄异株、克隆的物种的生殖生态进行了研究。具体地说，对10个冷水莲种群和9个高山紫荆种群的植株大小(样方植物的营养盖度)、花器陈列(每花序花数、每样方花序数)和性别比(雌性样方中有花的比例)进行了研究。菊科(Asteliaceae)新种。确实发生了性别二型性，雄性每花序多花(高山相思雄花比雌性多106%，冷杉雄性比雌性多12%)，每样方花序比雌性多(高山相思雄性花序比雌性多78%，冷杉雄性花序比雌性多46%)。植株大小在两个物种的雌雄样方之间没有差异，也没有男性偏向的性别比例。然而，冷蒿的植株大小与开花状态有关，65个不开花的样方的营养盖度低于175个开花样方，这表明该物种在开花前可能需要一个最小的大小/盖度。对于高山相思，随机抽样的185个样方中，除了两个之外，所有的样方都开花了。海拔高度对植株大小的影响不大，海拔对两种植物的花卉展示影响很小，但随着海拔的升高，冷蒿的花序数略有增加，高山相思雌株的花序花数略有减少。
Sexual dimorphism and male biased sex ratios have been predicted for dioecious plants experiencing the limited conditions for growth and reproduction found in many alpine environments. To test these predictions, the reproductive ecology of two congeneric, co-occurring, dioecious, clonal, species was examined in the subalpine and alpine zones of Kosciuszko National Park, southeastern Australia. Specifically, plant size (vegetative cover of plants in quadrats), floral display (number of flowers per inflorescence, number of inflorescences per quadrat) and sex ratios (proportion of females in quadrats with flowers) were examined in ten populations of Astelia psychrocharis (Asteliaceae) and nine populations of Astelia alpina var. novae-hollandiae (Asteliaceae). Sexual dimorphism did occur, with males having more flowers per inflorescence (106% more flowers for A.alpina males and 12% more for A.psychrocharis males compared to females) and more inflorescences per quadrat than females (78% more inflorescences for A.alpina males and 46% more inflorescences for A.psychrocharis males compared to females). Plant size did not differ between male and female quadrats of either species, nor were there male biased sex ratios. However, plant size was related to flowering status in A.psychrocharis with the 65 quadrats that did not flower having lower vegetative cover than the 175 flowering quadrats indicating that there may be a minimum size/ cover required prior to flowering in this species. For A.alpina, all but two of the 185 quadrats randomly sampled flowered. There was no effect of altitude on plant size and very little effect of altitude on floral display for either species, apart from a slight increase in the number of inflorescences per quadrat with increasing altitude for A.psychrocharis, and slight decrease in number of flowers per inflorescence with increasing altitude for A.alpina females.