青藏高原晚期开花植物线叶龙胆的传粉生态学  

POLLINATION ECOLOGY OF GENTIANA LAWRENCEI VAR. FARRERI,A LATE-FLOWERING QINGHAI-TIBET PLATEAU SPECIES

作　　者：侯勤正[1,3] 段元文[2] 司庆文[1,3] 杨慧玲[1] 

机构地区：[1]中国科学院西北高原生物研究所,中国科学院高原生物适应与进化重点实验室,西宁810008 [2]中国科学院青藏高原研究所昆明分部,昆明650204 [3]中国科学院研究生院,北京100049

出　　处：《植物生态学报》2009年第6期1156-1164,共9页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(30572329);西部博士项目

摘　　要：线叶龙胆(Gentiana lawrencei var.farreri)主要分布在青藏高原,在晚秋和早冬开花。为了探明线叶龙胆繁育系统特点,探讨其对环境的繁殖适应特征,对其传粉生态学过程进行了连续3年的观察。线叶龙胆自然状态下的结籽率很低,存在严重的花粉限制。雌雄异位和不完全雌雄异熟的花特征表明其结实必须依赖昆虫传粉。繁育系统实验表明,部分套袋花也能结实,这可能主要是由蓟马(Thripidae spp.)和蚂蚁(Formica spp.)等小昆虫协助自交所致。克什米尔熊蜂(Bombus kashmirensis)和苏氏熊蜂(B.sushikini)是线叶龙胆的有效传粉昆虫,但其访花频率非常低,分别为0.006和0.005time.flower-1.h-1。线叶龙胆花持续期和柱头可授能力都长于其他已报道的龙胆类植物,从而在温度低、传粉昆虫少的情况下提供了更多传粉机会。线叶龙胆同时具有协助自交和杂交的繁殖现象,以及较长的花持续期和柱头持续能力,这可能是其在青藏高原地区赖以存活和延续的一个重要原因。Aims Gentiana lawrencei var. farreri （Gentianaceae）,a late-autumn or early-winter flowering alpine perennial,is distributed mainly in the northeastern Qinghai-Tibetan Plateau （QTP）. The environment of the QTP is harsh because temperature is low and insects are scarce. Our aim is to exam-ine the pollination ecology of G. lawrencei and its adaptive relationship with the environment. Methods The pollination ecology of G. lawrencei was documented for three consecutive years in northeastern QTP. The breeding system was tested and floral visitors were observed during the flower life span. Flower longevity was recorded and stigma receptivity was tested by the seed-set ratio of dif-ferent days in which the stigma was presented. Important findings The seed-set of G. lawrencei under natural conditions was extremely low because of pollen-limitation. Combined characters of herkogamy and incomplete dichogamy indicate that polli-nators are needed for complete pollination. Some individuals of G. lawrencei could produce seeds under bagging without emasculation,and it may be from selfing caused by thrips and ants. Bombus kash-mirensis and B. sushikini are effective pollinators of G. lawrencei,but the frequencies of visits are ex-tremely low （0.006 and 0.005 time.flower–1.h–1,respectively）. Floral longevity and stigma receptivity are relatively long compared with other Gentianaceae species,and these increase the probability of pollination chances under low temperature and low pollinator conditions. The combination of self-and cross-pollination,as well as the prolonged floral longevity and stigma receptivity,may be the main reason for the survivorship of G. lawrencei.

关 键 词：线叶龙胆 晚花期植物 传粉生态学 长花期 繁殖策略 

分 类 号：Q948[生物学—植物学]