Ricci Nícolas Alberto Polizelli, Bento João Pedro Silvério Pena, Mayer Juliana Lischka Sampaio, Singer Rodrigo Bustos, Koehler Samantha
Programa de Pós-Graduação em Biologia Vegetal, Universidade Estadual de Campinas, Campinas, SP, Brazil.
Departamento de Biologia Vegetal, Instituto de Biologia, CP 6109, Universidade Estadual de Campinas, Campinas, SP, 13083-970, Brazil.
Protoplasma. 2024 Mar;261(2):271-279. doi: 10.1007/s00709-023-01895-x. Epub 2023 Oct 3.
Gametophytic self-incompatibility (GSI) has been mainly described in species-rich clades within Orchidaceae. We report GSI for a genus within Maxillariinae, one of the most conspicuous and diverse subtribes of neotropical orchids. Here, we describe the reproductive system of Brasiliorchis picta, B. phoenicanthera, and B. porphyrostele. Anatomical studies of fruit development showed that pollen tubes of aborted, self-pollinated flowers degenerate half-way in the stylar channel and never reach the ovules. Spontaneous self-pollination and emasculation set no fruits for none of the sampled species, thus supporting the hypothesis that these three species studied rely on the agency of pollinators and pollinator-mediated cross-pollination to set fruit. Fruit set from cross-pollinations ranged from 33.4 to 77.5%. One self-pollinated fruit of B. porphyrostele developed to completion. All other fruits aborted between 10 and 21 days after pollination. These data support previous evidence of variable strength GSI being exhibited in orchid species. Additional studies of self-incompatibility systems are needed to evaluate their role in species diversification and evolution of reproductive strategies in Maxillariinae and to allow for effective conservation strategies of threatened orchid species.
配子体自交不亲和性（GSI）主要在兰科植物种类丰富的分支中被描述。我们报道了新热带兰最显著且多样的亚族之一颚唇兰亚族中一个属的GSI。在此，我们描述了彩花巴西兰、红花药巴西兰和紫柱巴西兰的生殖系统。果实发育的解剖学研究表明，自花授粉后败育花朵的花粉管在花柱通道中途退化，从未到达胚珠。自发自花授粉和去雄处理对所有采样物种均未结出果实，从而支持了这样的假设，即所研究的这三个物种依靠传粉者媒介和传粉者介导的异花授粉来结实。异花授粉的结实率在33.4%至77.5%之间。紫柱巴西兰的一个自花授粉果实发育成熟。所有其他果实在授粉后10至21天之间败育。这些数据支持了先前关于兰花物种表现出可变强度GSI的证据。需要对自交不亲和系统进行更多研究，以评估其在颚唇兰亚族物种多样化和生殖策略进化中的作用，并为受威胁兰花物种制定有效的保护策略。
