%0 Journal Article
%T Ecological significance of fruit heteromorphism in the annual ephemeral Senecio subdentatus<br>一年生短命植物疏齿千里光果实异形性的生态学意义
%A JANNATHAN Mamut
%A TAN Dun-Yan
%A CHENG Xiao-Jun
%A <br>吉乃提汗·马木提
%A 谭敦炎
%A 成小军
%J 植物生态学报
%D 2011
%I Editorial Office of Chinese Journal of Plant Ecology
%X Aims Senecio subdentatus (Asteraceae) is an annual ephemeral in the Gurbantunggut Desert, northern Xinjiang, China. It produces two morphs of achenes in the same infructescence. Our aim was to determine the morphological, dispersal and germination characteristics of the heteromorphic achenes and the relationship between size and yield of plants produced by them. Methods Shape, size, surface ornamentation (via SEM micrographs), dispersal, germination of the two morphs of achenes, number of peripheral and central achenes per infructescence and per plant and plant biomass were determined in the laboratory. The mode and duration of achene dispersal were measured in the field. Important findings The peripheral and central achenes are columnar, but they are significantly different in size, color, length of pappus and pericarp micro-morphology. Peripheral achenes are pale yellow and central ones brown. There are no differences in rate of descent in still air or dispersal distance at wind speeds of either 1 or 2 m·s–1. Therefore, the dispersal ability of the two achene morphs was not significantly affected by achene size or length of pappus. The germination percentages were higher for 1-month old peripheral achenes at 5/2, 15/2, 20/10, 25/15 and 30/15 °C, and there were significant differences among temperatures in both achene morphs. Light did not affect germination significantly. There are more peripheral than central achenes in a capitulum. The proportion of peripheral achenes in an individual was negatively correlated with plant size, while the proportion of central achenes was positively  correlated with plant size. This suggests that small plants produce more peripheral achenes with higher germination percentages, while large plants produce more central achenes with lower germination percentages. In the unpredictable environment of the Gurbantunggut Desert, plant size of S. subdentatus is closely related to micro-habitat. This species can reduce competition among siblings and increase adaptive responses to different micro-environmental conditions by making full use of germination differences between peripheral and central achenes and regulating yield of both achenes in different plant sizes.
%K achene yield
%K annual ephemeral
%K dispersal
%K ecological adaptations
%K germination
%K fruit heteromorphism
%K morphology characteristics
%K Senecio subdentatus<br>瘦果产量
%K 一年生短命植物
%K 扩散
%K 生态适应
%K 萌发
%K 果实异形性
%K 形态特征
%K 疏齿千里光
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=90BA3D13E7F3BC869AC96FB3DA594E3FE34FBF7B8BC0E591&jid=2F2173CCFF292BF447DC2681EA33BBAE&aid=8C7BD152C148DE185511CB6210DEEAFB&yid=9377ED8094509821&vid=6209D9E8050195F5&iid=B31275AF3241DB2D&sid=46FF101E7ECF9F15&eid=93661EC4C0CCEA67&journal_id=1005-264X&journal_name=植物生态学报&referenced_num=0&reference_num=52