Abstract

The present study describes the floral morphology and evaluates pollen viability for the bromeliad Nidularium minutum Mez. during the flowering period 2018‒2019 through histochemistry and pollen germination tests. The inflorescences are nidular, capituliform with short branches bearing two to three odourless, bisexual and greenish-white flowers and with an androecium shorter than the gynoecium, consisting of six stamens with anthers featuring rimose dehiscence. The ovules are anatropous, displaying a small appendage in the chalazal region. The first flower opened in late November 2018 and flowering peak was in January 2019. Anthesis started at 6:55 a.m. and lasted until 8:49 a.m. Pollen/ovule ratio indicates facultative autogamy. The pollen grains are monads, medium to large, 2-(3)-porate, reticulate heterobrochate with abundant pollenkitt. A high frequency of unviable pollen grains with discrepant sizes was observed. The mature pollen grain is considered recalcitrant and therefore sensitive to desiccation. In vitro pollen germination after 48 hours was higher in BKM medium (64.77%) compared to SM (38.51%). Pollen viability was overestimated in all histochemistry tests, with Alexander (72.46%) being the closest to the in vitro germination rate. The results obtained for N. minutum bring new information about its floral biology as a subsidy to the cultivation of ornamental bromeliads that are at risk of extinction.

摘要

本研究描述了凤梨科植物 Nidularium minutum的花形态并评估了花粉活力梅兹。2018-2019 开花期通过组织化学和花粉萌发试验。花序为球形，头状花序，短枝上有两到三朵无味、两性和绿白色的花，雄蕊花比雌蕊花短，由六个雄蕊组成，花药具有边缘开裂的特征。胚珠是倒生的，在合点区域显示一个小的附属物。第一朵花于 2018 年 11 月下旬开放，开花高峰期为 2019 年 1 月。花期从上午 6:55 开始，一直持续到上午 8:49。花粉/胚珠比率表明兼性自配。花粉粒是单子，中到大，2-(3)-多孔，网状异芽孢，有丰富的花粉. 观察到高频率的具有差异大小的不能存活的花粉粒。成熟的花粉粒被认为是顽固的，因此对干燥敏感。与 SM (38.51%) 相比，BKM 培养基中 48 小时后的体外花粉萌发率 (64.77%) 更高。在所有组织化学测试中，花粉活力被高估，亚历山大 (72.46%) 最接近体外萌发率。为N获得的结果。minutum带来了有关其花卉生物学的新信息，作为对濒临灭绝的观赏凤梨科植物栽培的补贴。