荒漠春季开花植物大花驼蹄瓣的传粉生物学研究OA

Zygophyllum potaninii is a spring-flowering perennial herb widely distributed in the gravelly desert of northern Xinjiang.To mechanistically investigate pollination by this species,flowering phenology,single flowering process,floral characteristics,pollination characteristics,and breeding system were studied in field and controlled experiments.These studies revealed:1)the native population flowering period was from late April to mid-May,with respective population and individual flowering periods of 23 and 14 days.The population flowering process displayed a progressive unimodal curve with high synchronization among individuals,resulting in a concentrated flowering pattern.2)this species exhibits both protogyny and pollen presentation schedules during its flowering phase,and duration of the female stage was significantly lower than that of the female stage(P<0.001).Ten anthers matured successively with no significant differences in their dispersion durations(P=0.526)and an average dispersion time of 3.66 h.While no overlap occurred between the first two anther dispersal times,some overlap occurred among the last eight anther dispersals:Average overlap time was 1.69 h.3)The flowers are bisexual and detached;sepals are green and obovate in shape;petals are white and obovate;pollen color is yellow-orange,and pollen is accompanied by nectar although no floral scent has been detected.4)Six pollinators were observed,all of which were bees.The main pollinators Osmia sp.and Chalicodoma desertorum exhibited the highest respective flower-visiting frequencies of 0.65 and 0.31 times·(flower·h)-1.5)The breeding system of this species is classified as facultative outcrossing,characterized by the absence of apomixis and anemophilous pollination.Based on the pollinator abundance scenario,Z.potaninii can ensure reproduction by autonomous selfing and attracting pollinators to encourage outcrossing in the spring desert environment.This mechanism results from the species'adaptation to its harsh desert environment to ensure its reproductive success and population expansion in an unpredictable habitat.