Basist Georgia, Dyer Adrian G, Garcia Jair E, Raleigh Ruth E, Lawrie Ann C
School of Science, RMIT University, Bundoora, VIC, Australia.
Bio-inspired Digital Sensing Lab, School of Media and Communication, RMIT University, Melbourne, VIC, Australia.
Front Plant Sci. 2021 Feb 9;12:599874. doi: 10.3389/fpls.2021.599874. eCollection 2021.
G.W. Carr (Tawny Spider-orchid) is a terrestrial Australian endangered orchid confined to contiguous reserves in open woodland in Victoria, Australia. Natural recruitment is poor and no confirmed pollinator has been observed in the last 30 years. Polymorphic variation in flower color complicates plans for artificial pollination, seed collection and propagation for augmentation or re-introduction. DNA sequencing showed that there was no distinction among color variants in the nuclear ribosomal internal transcribed spacer (ITS) region and the chloroplast trnT-trnF and matK regions. Also, authentic specimens of both and from the reserves clustered along with these variants, suggesting free interbreeding. Artificial cross-pollination and assessment of seed viability further suggested that no fertility barriers existed among color variants. Natural fruit set was 15% of the population and was proportional to numbers of the different flower colors but varied with orchid patch within the population. Color modeling on spectral data suggested that a hymenopteran pollinator could discriminate visually among color variants. The similarity in fruiting success, however, suggests that flower color polymorphism may avoid pollinator habituation to specific non-rewarding flower colors. The retention of large brightly colored flowers suggests that has maintained attractiveness to foraging insects rather than evolving to match a scarce unreliable hymenopteran sexual pollinator. These results suggest that should be recognized as encompassing plants with these multiple flower colors, and artificial pollination should use all variants to conserve the biodiversity of the extant population.
G.W.卡尔（黄褐蜘蛛兰）是一种澳大利亚本土的陆生濒危兰花，仅分布于澳大利亚维多利亚州开阔林地中相邻的保护区。自然更新情况不佳，在过去30年里未观察到已确认的传粉者。花色的多态性变异使人工授粉、种子采集以及用于种群增加或重新引入的繁殖计划变得复杂。DNA测序表明，在核糖体内部转录间隔区（ITS）、叶绿体trnT - trnF和matK区域，颜色变异体之间没有区别。此外，来自保护区的这两种颜色变异体的真实标本与这些变异体聚集在一起，表明存在自由杂交。人工异花授粉和种子活力评估进一步表明，颜色变异体之间不存在育性障碍。自然坐果率为种群的15%，与不同花色的数量成比例，但在种群内随兰花斑块而变化。基于光谱数据的颜色建模表明，一种膜翅目传粉者能够在视觉上区分颜色变异体。然而，结果相似表明花色多态性可能避免传粉者对特定无回报花色产生习惯。保留大的鲜艳花朵表明黄褐蜘蛛兰一直保持着对觅食昆虫的吸引力，而不是进化到去匹配稀少且不可靠的膜翅目有性传粉者。这些结果表明，黄褐蜘蛛兰应被认定为包含这些多种花色的植物，并且人工授粉应使用所有变异体以保护现存种群的生物多样性。
