how are large pollen grains transferred from the anther to the stigma?
Answers
Answer:
Conclusions
The mode of self-pollination discussed here is a new addition to the broad range of genetic and morphological mechanisms that have evolved in flowering plants to ensure their reproductive success. The present self-contained pollination mechanism is a possible adaptation to the insect-scarce habitat of the orchid.
Introduction
Reproduction plays a key role in the process of plant evolution. The transformation of the reproductive system from outcrossing to selfing is the most common change in the evolution of angiosperms [1]. Owing to the frequent occurrence of inbreeding depression, plants have evolved numerous mechanisms to avoid selfing [2]. This phenomenon has resulted in promoting the space–time separation of male and female functions (e.g., dioecy, dichogamy, herkogamy, enantiostyly, and heterostyly) [3]. The purposes of this separation are to avoid the disturbance between pollen exportation (male function) and reception (female function), and achieve the accuracy of pollen transmission to reduce pollen waste [1], [4]. However, present-day plants have a high ratio of selfing. Darwin considered the assurance of reproduction to be the most important factor [5] that enables plants to develop selfing mechanisms. In environments where the external pollen is inadequate (e.g., due to a very low population density and few pollinators) and results in a failure of outcrossing, selfing is selected to ensure the fertilization of ovules or to obtain reproductive assurance. However, this process may cause a marked and rapid decrease in inbreeding [6]–[8].
Answer:
the large pollen grains can be transferred to stigma by wind or any other animal .
this process is called pollination
hope it helps you
please mark as brainliest
Explanation: