Maize Male Reproductive Organs Affected by Different Timings of Water Deficit

Compared with female reproductive organs, the development of male reproductive organs was got less attention in maize because of its oversupply in amount even under water deficit. Thus, a rainout shelter experiment was designed to explore the effect of different timings of water deficit on pollen vitality and exterior and interior ultra-structure of pollen grains, starch particles in pollen grains, anther fresh weight, and vascular bundle number and its organizational structure in tassel pedicel. There were five water treatments included in this study, viz. well water treatment (CK), water deficit during 6- to 8- leaf stage (V6 − 8), 9- to 12- leaf stage (V9 − 12), 13-leaf stage to tasseling (V13 − T), and silking to blister (R1 − 2), respectively. Results showed that the percentage of pollen grains with strong vitality decreased remarkably by 27.3–45.9% under water deficits, while that of pollen grains with weak vitality increased by 27.2–34.7%. The percentage of pollen grains with no vitality was significantly increased only when water deficit occurred around silking, which was up to 8.6% for V13 − T and 19.7% for R1 − 2 compared with 1.0% for that of CK. Both shrunken pollen apertures (including annulus and operculum) and less starch particles might partially explain the weakened pollen vitality for water deficits before tasseling. Furthermore, the assimilation flux to male reproductive organs might be restricted by the influenced vascular bundle system under water deficits before tasseling, with manifestation showing in anther fresh weight and starch particle status in pollen grains. Specifically, V9 − 12 and V13 − T water deficits delayed differentiation of vascular bundle but had no influence on vascular bundle number, which might be one reason for their decreased anther fresh weight and less starch particles in pollen grains. Conversely, V6 − 8 water deficit significantly decreased vascular bundle number but had no significant influence on anther fresh weight and starch particles in pollen grains. R1 − 2 water deficit almost had no influences on above indicators except for pollen vitality. Overall, this research highlight that male reproductive organs could be influenced by water deficits in maize, which deserves more attention in further breeding especially under the background of high-quality requirement for pollen vitality of the maize hybrids that have a small tassel size.

Blocked pollen release prevents fruit formation in the halophyte Elaeagnus angustifolia in non-saline habitats

Background: Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can bear fruits when grown in saline soils. However, no fruits are born in non-saline soils. The possible reasons and differences in E. angustifolia under two conditions were elucidated. Results: We examined features including pollen vitality and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen vitality or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. And the differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormones, cell wall secondary thickening, transcription factors and ion transport. Conclusions: E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.

Blocked pollen release prevents fruit formation in the halophyte Elaeagnus angustifolia in non-saline habitats

Background: Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can bear fruits when grown in saline soils. However, no fruits are born in non-saline soils. The possible reasons and differences in E. angustifolia under two conditions were elucidated.Results: We examined features including pollen vitality and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen vitality or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. And the differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormones, cell wall secondary thickening, transcription factors and ion transport.Conclusions: E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.

Blocked Pollen Release Prevents Fruit Formation in the Halophyte Elaeagnus Angustifolia in Non-Saline Habitats

Background: Anther development affects the reproduction of flowering plants. Halophyte Elaeagnus angustifolia can produce fruits when grown in saline soils. However, no fruits are produced in non-saline soils. The possible reasons and differences in E. angustifolia under two conditions were elucidated. Results: We examined features including pollen vitality and germination, in situ pollen germination after natural and hand pollination, anthers after pollen release, and the transcriptome in anthers. No significant difference was observed in pollen vitality or stigma receptivity in E. angustifolia in non-saline vs. saline habitats. However, no pollen tubes were present in styles, and pollen grains were abundant in E. angustifolia anthers under non-saline conditions. Notably, many pollen tubes formed in styles of E. angustifolia after hand pollination in the non-saline habitat. And the differentially expressed genes in anthers from saline vs. non-saline habitats were mainly related to phytohormones, cell wall secondary thickening, transcription factors and ion transport. Conclusions: E. angustifolia fail to form fruits in non-saline habitats due to poor anther pollen release. The induction and coordinated upregulation of genes related to anther cell wall formation and JA biosynthesis likely contribute to anther dehiscence in E. angustifolia in saline habitats, whereas anther dehiscence is blocked in plants grown in non-saline habitats.

Effects of Jasmonate on Ethylene Function during the Development of Tomato Stamens

The phenotype of the tomato mutant jasmonate-insensitive1-1 (jai1-1) mutated in the JA-Ile co-receptor COI1 demonstrates JA function in flower development, since it is female-sterile. In addition, jai1-1 exhibits a premature anther dehydration and pollen release, being in contrast to a delayed anther dehiscence in the JA-insensitive Arabidopsis mutant coi1-1. The double mutant jai1-1 Never ripe (jai1-1 Nr), which is in addition insensitive to ethylene (ET), showed a rescue of the jai1-1 phenotype regarding pollen release. This suggests that JA inhibits a premature rise in ET to prevent premature stamen desiccation. To elucidate the interplay of JA and ET in more detail, stamen development in jai1-1 Nr was compared to wild type, jai1-1 and Nr regarding water content, pollen vitality, hormone levels, and accumulation of phenylpropanoids and transcripts encoding known JA- and ET-regulated genes. For the latter, RT-qPCR based on nanofluidic arrays was employed. The data showed that additional prominent phenotypic features of jai1-1, such as diminished water content and pollen vitality, and accumulation of phenylpropanoids were at least partially rescued by the ET-insensitivity. Hormone levels and accumulation of transcripts were not affected. The data revealed that strictly JA-regulated processes cannot be rescued by ET-insensitivity, thereby emphasizing a rather minor role of ET in JA-regulated stamen development.