旱麦草属4种短命植物的结实特性及生殖包装

旱麦草属（Eremopyrum）是禾本科小麦族中的一个一年生属.全世界共有8种,我国有4种,分别为：东方旱麦草（E. oriental）、毛穗旱麦草（E. distans）、光穗旱麦草（E. bonaepartis）和旱麦草（E. triticeum）,它们仅分布于新疆北部,是准噶尔荒漠中常见的短命植物,具有重要的生态和饲用价值.本文采用野外、田间与室内观测相结合的方法,首次对这4种短命植物秋萌株的生殖分配、结实特性、生殖包装等方面进行了研究,并对其在准噶尔荒漠中的生殖适应对策进行了探讨.主要结果如下：1）生殖分配高达55%～60%,远高于大多数一年生和多年生植物;2） 结实率在60%至80%;单株结实量约为100至500粒;3） 生殖包装单位由内外稃与包裹于其中的颖果共同组成.颖果与稃粘生,稃的重量占整个包装单位重量的15%至60%,这种对生殖包装较高比例的资源投入,提高了其果实在荒漠环境中的适合度;4） 多以小穗为扩散单位,这种独特的扩散方式,增加了种子（颖果）及幼苗在荒漠环境中萌发及生存的可能性.

The Characteristics of Fruit-set and Reproductive Package in Four Species of Ephemeral Plants in Eremopyrum (poaceae)

Eremopyrum is a small genus in tribe Triticeae(Poaceae) with eight species all over the world.In China,there are four species distributed only in the north part of Xinjiang.In Junggar desert,the four species belong to typical ephemeral plants and are of very important ecological and applied value.By observations in field and laboratory,the characteristics of reproductive allocation,patterns of fruit-set and reproductive package of the four species were compared with each other and analyzed,and the survival strategies of these species in the extreme environment of Junggar desert were discussed in this paper.The main results are as follows:1) The plants of four species favor to allocate a greater proportion of resources to reproductive activities,the proportion of their reproductive allocation(RA) can reach 55%-60%,and is higher than that of most annual and perennial plants.2) Their fruit-set ratios are 60%-80%,and fruits yield of plant can reach 100-500 grains.3) The reproductive package unit of four species is composed of bracts and caryopses,and percentages of bracts weight in reproductive package unit are 15%-60%.The fruit fitness was enhanced by inputting high recourse to productive package.4) The dispersal unit in E. oriental,E.distans,E.bonaepartis is spikelets,and in E.triticeum is both seeds and in florescence.All the characteristics are important for these species to adapt the extreme environment of Junggar desert and assure their reproductive success.