Pollen grains have a relatively simple structure and microscopic size, with two or three cells surrounded by the protective sporoderm at maturity. The viability and efficiency of pollen transport from anther to stigma depends on pollen physiological properties, especially the relative water content of the vegetative cell. Pollen transport is a crucial fate for most angiosperms that depends on biotic pollinators and studies focusing on understanding the morpho-physiological properties of pollen grains are still scarce, especially to tropical open physiognomies as the Brazilian Cerrado. Therefore, we investigate some structural and physiological aspects of pollen grains from six native species naturally growing in one Cerrado area: Campomanesia pubescens (Myrtaceae), Caryocar brasiliense (Caryocaraceae), Erythroxylum campestre (Erythroxylaceae), Lippia lupulina (Verbenaceae), Pyrostegia venusta (Bignoniaceae), and Xylopia aromatica (Annonaceae). We selected dehiscent anthers and mature pollen grains to analyze (1) the anther wall and pollen microstructure, (2) the pollen water status at the time of anther dehiscence, and (3) the pollen chemical compounds. In all analyzed species, the anther and pollen developed in a successfully way, and except for Caryocar brasiliense, all species were able to emit pollen tubes in the germination tests. As expected for a dry and open environment, most species dispersed their pollen grains in a partially dehydrated form, as indicated by our harmomegathy experiment. As indicated by our study, the pollen ability in preventing dissection, maintaining its viability in a dry and hot environment during its transport from anther to stigma, may be related to the sporoderm apertures and to the reserve compounds, mainly carbohydrates in the form of hydrolysable starch grains.

花粉粒具有相对简单的结构和微观尺寸，成熟时有两个或三个细胞被保护性子胚层包围。花粉从花药运输到柱头的活力和效率取决于花粉的生理特性，尤其是营养细胞的相对含水量。对于大多数依赖生物传粉媒介的被子植物来说，花粉运输是一个至关重要的命运，而专注于了解花粉粒形态生理特性的研究仍然很少，特别是对于热带开放地貌，如巴西塞拉多。因此，我们研究了在 Cerrado 地区自然生长的六种本地物种的花粉粒的一些结构和生理方面：Campomanesia pubescens（桃金娘科）、Caryocar brasiliense（石蕊科）、Erythroxylum campestre（Erythroxylaceae）、Lippia lupulina（马鞭草科）、Pyrostegia venusta（Bignoniaceae）和Xylopiaaromatica（番荔枝科）。我们选择开裂的花药和成熟的花粉粒来分析（1）花药壁和花粉微观结构，（2）花药开裂时的花粉水分状态，以及（3）花粉化学成分。在所有分析的物种中，花药和花粉均以成功的方式发育，但巴西石蕊除外，在发芽测试中，所有物种都能够发射花粉管。正如我们对干燥和开放环境所预期的那样，大多数物种以部分脱水的形式分散它们的花粉粒，正如我们的harmomegathy实验所表明的那样。正如我们的研究所表明的那样，花粉在从花药到柱头的运输过程中防止分离、在干燥和炎热的环境中保持活力的能力可能与孢皮孔和储备化合物有关，主要是可水解形式的碳水化合物淀粉粒。