CAJ | 학술논문

线叶龙胆(Gentiana lawrencei vat.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,部分套袋化也能结实,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月胆类植物,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.
선협룡담(Gentiana lawrencei vat.farreri)주요분포재청장고원,재만추화조동개화.위료탐명선협룡담번육계통특점,탐토기대배경적번식괄응특정,대기전분생태학과정진행료련속3년적관찰.선협룡담자연상태하적결자솔흔저,존재엄중적화분한제.자웅이위화불완전자웅이숙적화특정표명기결실필수의뢰곤충전분.번육계통실험표명,부분투대화야능결실,저가능주요시유계마(Thripidae spp.)화마의(Formica spp.)등소곤충협조자교소치.극십미이웅봉(Bombus kashmirensis)화소씨웅봉(B.sushikini)시선협룡담적유효전분곤충,단기방화빈솔비상저,분별위0.006화0.005time·flower~(-1)·h~(-1) .선협룡담화지속기화주두가수능력도장우기타이보도적룡월담류식물,종이재온도저、전분곤충소적정황하제공료경다전분궤회.선협룡담동시구유협조자교화잡교적번식현상,이급교장적화지속기화주두지속능력,저가능시기재청장고원지구뢰이존활화연속적일개중요원인.
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 examine 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 different 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 pollinators 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 extremely 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.