Department of Botany, University of Chittagong, Chittagong, Bangladesh.
Plant Biol (Stuttg). 2012 Mar;14(2):278-84. doi: 10.1111/j.1438-8677.2011.00507.x. Epub 2011 Sep 8.
No comparative study of floral senescence following male function among a range of tropical orchid genera has previously been undertaken. The timing and pattern of floral senescence and occurrence of fruit formation were studied following self-, geitonogamous and cross-pollination in 14 epiphytic and two terrestrial orchid species to determine their breeding system and assess the occurrence of floral abscission following pollinaria removal. Both pollination and pollinaria removal caused rapid floral senescence, and the pattern and timing of the floral changes were the same in all treatments. Six Dendrobium species and Pelatantheria insectifera were self-incompatible (SI) and eight other species, including one terrestrial species, were self-compatible (SC). Capsules produced from outcrossing in four SC species, Phalaenopsis cornu-cervi, Eria pubescens, Cleisostoma appendiculatum and Arundina graminifolia, were larger and heavier than those produced after selfing. Reductions in flower life span following pollinaria removal were positively correlated with flower size and longevity of unpollinated flowers but not with position in the inflorescence or nature of the breeding system. Rapid flower senescence following pollinaria removal reported here suggests that it may be widespread in tropical species. The significant association of the response with size of flowers and inflorescences among the species studied suggests that the cost of flower maintenance outweighs the benefit of remaining open for female function after pollinaria have been removed. Both SC and SI species were found among tropical orchids, but variation in capsule size following self- and cross-pollination indicates that there may be a reduction in seed production following selfing, even in SC species, and that fruit formation alone should not be taken as reliable evidence of full self-compatibility.
此前，尚未对一系列热带兰属植物的雄性功能后花朵衰老进行过比较研究。本研究对 14 种附生兰花和 2 种陆生兰花进行自交、同株异花授粉和异花授粉，以研究其传粉后花朵衰老和果实形成的时间和模式，以确定其繁殖系统，并评估在移除花粉粒后花朵是否会脱落。授粉和移除花粉粒都会导致花朵迅速衰老，而且所有处理方式下花朵的变化模式和时间都相同。6 种石斛和 Pelatantheria insectifera 为自交不亲和（SI），另外 8 种兰花，包括 1 种陆生兰花，为自交亲和（SC）。在 4 种 SC 物种，即蝴蝶兰、毛兰、竹叶兰和文心兰中，异交产生的蒴果比自交产生的蒴果更大、更重。在移除花粉粒后，花的寿命缩短与花的大小和未授粉花的寿命呈正相关，但与花序中的位置或繁殖系统的性质无关。这里报道的移除花粉粒后花朵迅速衰老表明，它可能在热带物种中广泛存在。在研究的物种中，花朵大小和花序与移除花粉粒后的反应之间存在显著的关联，这表明在移除花粉粒后，花朵维持开放以进行雌性功能的成本超过了留在开放状态的好处。在热带兰花中发现了 SC 和 SI 物种，但自交和异交后蒴果大小的变化表明，即使在 SC 物种中，自交也可能导致种子产量减少，而且仅果实形成不应被视为完全自交亲和的可靠证据。
