Pollen Developmental Arrest: Maintaining Pollen Fertility in a World With a Changing Climate

Abstract

During evolution of land plants, the haploid gametophytic stage has been strongly reduced in size and the diploid sporophytic phase has become the dominant growth form. Both male and female gametophytes are parasitic to the sporophyte and reside in separate parts of the flower located either on the same plant or on different plants. For fertilization to occur, bi-cellular or tri-cellular male gametophytes (pollen grains) have to travel to the immobile female gametophyte in the ovary. To survive exposure to a hostile atmosphere, pollen grains are thought to enter a state of complete or partial developmental arrest (DA). DA in pollen is strongly associated with acquisition of desiccation tolerance (DT) to extend pollen viability during air travel, but occurrence of DA in pollen is both species-dependent and at the same time strongly dependent on the reigning environmental conditions at the time of dispersal. Several environmental stresses (heat, drought, cold, humidity) are known to affect pollen production and viability. Climate change is also posing a serious threat to plant reproductive behavior and crop productivity. It is therefore timely to gain a better understanding of how DA and pollen viability are controlled in plants and how pollen viability can be protected to secure crop yields in a changing environment. Here, we provide an overview of how DA and pollen viability are controlled and how the environment affects them. We make emphasis on what is known and areas where a deeper understanding is needed.

Success Rate of Individual Pollinizers for the Pear Cultivars “Ingeborg” and “Celina” in a Nordic Climate

“…Many factors influence pollen germination: time of collection, the season, conditions of pollen storage and others. The obtained results indicated that this trait is under the strong influence of ecological factors, which was previously reported for other fruit species [35,38]. In this study, it was particularly pronounced in the cultivar "Conference", which showed the highest difference in pollen germination in vitro between two years.…”

Engineering 6-phosphogluconate dehydrogenase to improve heat tolerance in maize seed development

“…High temperatures affect grain yield with up to 50% yield loss, which can be caused by a variety of mechanisms (22)(23)(24)(25)(26)(27). Heat can reduce seed set by accelerating plant development, causing asynchrony between male and female gamete development as well as reducing ovary and pollen viability (28)(29)(30). Accelerated development during grain-fill reduces the time available for seed storage molecule accumulation (6).…”

Abnormal Anther Development Leads to Lower Spikelet Fertility in Rice (Oryza Sativa L.) Under High Temperature During the Panicle Initiation Stage

“…2L and 7). Second, Pacini et al [44] indicated that anther stomata may play a crucial role in anther dehydration in rice, which may favor anther dehiscence and pollen shedding. Recently, in ICE1 (ice1-2) Arabidopsis mutants, Wei et al [45] found that decreased stomata density and abnormal stomata development were not advantageous for anther dehydration and anther water movement, so the epidermis did not shrink to dehisce, regardless of the existence of stomium cells in the anther; these changes resulted in low pollen dehiscence, low pollen viability and a low germination percentage.…”