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Climate change alters environmental conditions in ways that directly and indirectly affect plants. Flowering plants, for example, modify reproductive allocation in response to heat and drought stress, and such changes can in turn affect pollinator visitation and, ultimately, plant reproduction. Although the individual effects of warming and drought on plant reproductive allocation are well known, these factors may interact to influence reproduction. Here, we conducted a fully crossed temperature by irrigation manipulation in squash (Cucurbita pepo) to test how temperature and soil moisture variation affect pollinator‐mediated reproduction. To tease apart the direct and indirect effects of temperature and soil moisture, we compared hand‐pollinated plants to bee‐pollinated plants and restricted bee foraging (i.e., pollen transfer) to one experimental group per day. Temperature and soil‐moisture limitation acted independently of one another: warming decreased flower size and increased pollen production, whereas the effects of soil‐moisture limitation were uniformly inhibitory. While treatments did not change squash bee (Xenoglossa spp.) behavior, floral visitation by the honey bee (Apis mellifera) increased with temperature in male flowers and decreased with soil moisture in female flowers. Pollen deposition by bees was independent of plant soil moisture, yet reducing soil moisture increased pollen limitation. This result stemmed at least in part from the effects of soil‐moisture limitation on pollen viability; seed set declined with increasing deposition of fluorescent pigment (a proxy for pollen) from plants experiencing decreased soil moisture. These findings suggest that the transfer of lower‐quality pollen from plants experiencing soil‐moisture limitation led to drought‐induced pollen limitation. Similar effects may occur in a wide variety of flowering plant species as climate warming and drought increasingly impact animal‐pollinated systems. [ABSTRACT FROM AUTHOR]

Ipomoea triloba L., an annual twining herb, is considered an alien invasive species and is distributed all around the globe including tropical Asia. It affects the yield of various economically important crops. Studies on floral phenology and reproductive biology are fundamental for the development of management strategies and the conservation of plants. Hence, we investigated the phenology, floral biology, pollen viability, stigma receptivity, pollination mechanism, and reproductive success of I. triloba at two different locations in one of the global biodiversity hotspots. Floral anthesis was diurnal, starting at 6:30 a.m. and lasting until 7:00 a.m. Pollen viability and stigma receptivity were found to coincide, thus suggesting the species was homogamous. The flowers were mostly visited and pollinated by sweat bees (Halictidae), blue‐banded bees (Amegilla sp.), flies (Mesembrius sp.), and butterflies (Appias olferna, Pelopidas agna, and Zizina otis). Further, the pollinator visitation frequency showed a moderately positive correlation with the number of open flowers in both study populations. The plant produced fruits in the absence of pollinators in self‐pollination treatments, indicating a self‐compatible breeding system and dependency on insect pollination for reproductive success. Further, pollen supplementation significantly enhanced the fruit setting and mean seed per fruit at both study sites, suggesting pollen limitation. Additionally, pollen production and pollen/ovule ratio also indicated the facultative autogamous breeding system in I. triloba. Overall, these reproductive characteristics such as mixed mating systems and generalist insect visitation may allow the invasive I. triloba to establish new populations from low numbers of propagules. [ABSTRACT FROM AUTHOR]

• The flower visitation and seed set of S. daiguii in the TNFP was scarcely affected by biotic factors. • Seed set in the ZEFR was affected by serious pollen limitation. • Presence of fountains and increased humidity reduced the pollinator types, visitation frequency, and natural seed set of TNFP. • Higher daily temperatures reduced the pollinator abundance and visitation frequency in ZEFR. Salvia constitutes one of the largest genera in the Lamiaceae, with approximately 1,000 species found worldwide, and is recognized for its high ornamental and medicinal value. Salvia daiguii is a multipurpose perennial herb that grows on cliffs in the Zhangjiajie City, Hunan Province, China. Nevertheless, the pollination biology of vulnerable plants on cliffs, specifically the effects of abiotic factors on flower visitation and seed set, remains poorly understood. In this study, we observed the effects of biotic factors: flowering phenology and flower characteristics, flower longevity, nectar volume and concentration, pollen viability and stigma receptivity, pollinator visitation frequency, pollen remaining and deposition, and breeding systems, as well as abiotic factors: habitat fountain, temperature, and humidity, on the pollination and seed production of S. daiguii in two populations in Zhangjiajie City. The pollination biology results reveal that S. daiguii has a mixed mating system that depends on pollinators. The flower visitation and seed set of S. daiguii in the absence of natural fountain areas in Tianmenshan National Forest Park was scarcely affected by biotic factors. However, we observed a significant reduction in pollinator types, visitation frequency, and natural seed set of this population owing to abiotic factors, including the presence of a fountain habitat and increased humidity. Further, seed set in the Zhangjiaxi Ecological Forest Reserve was affected by both biotic (serious pollen limitation) and abiotic (higher population temperature) factors. We considered that pollinators types, flower visitation frequency, and natural seed set are vulnerable to the influence of ecological factors in fragmented habitats. Our results reveal the mechanisms contributing to the endangerment of species exemplified by S. daiguii and underscore the significance of conservation efforts for the sustainable use of other endangered species. [ABSTRACT FROM AUTHOR]

Context. Reproductive success in dioecious plant species may be limited by severe pollen limitation owing to their separate sexes and pollination barriers. Aims. Dodonaea viscosa subsp. angustifolia (Jacq.) (Sapindaceae) is a dioecious and wind-pollinated species that has a long flowering period. This study sought to determine the relationship between its reproductive behaviour and pollen availability during different flowering phases. Methods. Extra-stigmatic pollen germination and reproductive performance during different phases of flowering were investigated and correlated with pistil elongation under natural conditions. Results. The species offers whole stigmatic and stylar surfaces for pollen to land and germinate under natural conditions. During pollen-limiting conditions, the length of the pistil increases significantly to enhance pollen capture. Depending on where on the pistil pollen lands, the timing of pollen tube arrival at the ovary varies. Conclusions. Dodonaea viscosa subsp. angustifolia is the first reported wild species in the Sapindaceae where pistil elongation is regulated by pollination conditions and extra-stigmatic pollen germination ensures reproduction during phases of differing pollen availability. Our results indicated that the flexibility of female function and reproductive behaviour in Dodonaea viscosa subsp. angustifolia adds to the evolutionary possibilities to overcome pollination constraints. Implications. This unique strategy for increasing female fitness through pollen presentation in D. viscosa subsp. angustifolia could be explored in other subspecies of D. viscosa on the Australian subcontinent. [ABSTRACT FROM AUTHOR]

Abstract Climate change alters environmental conditions in ways that directly and indirectly affect plants. Flowering plants, for example, modify reproductive allocation in response to heat and drought stress, and such changes can in turn affect pollinator visitation and, ultimately, plant reproduction. Although the individual effects of warming and drought on plant reproductive allocation are well known, these factors may interact to influence reproduction. Here, we conducted a fully crossed temperature by irrigation manipulation in squash (Cucurbita pepo) to test how temperature and soil moisture variation affect pollinator‐mediated reproduction. To tease apart the direct and indirect effects of temperature and soil moisture, we compared hand‐pollinated plants to bee‐pollinated plants and restricted bee foraging (i.e., pollen transfer) to one experimental group per day. Temperature and soil‐moisture limitation acted independently of one another: warming decreased flower size and increased pollen production, whereas the effects of soil‐moisture limitation were uniformly inhibitory. While treatments did not change squash bee (Xenoglossa spp.) behavior, floral visitation by the honey bee (Apis mellifera) increased with temperature in male flowers and decreased with soil moisture in female flowers. Pollen deposition by bees was independent of plant soil moisture, yet reducing soil moisture increased pollen limitation. This result stemmed at least in part from the effects of soil‐moisture limitation on pollen viability; seed set declined with increasing deposition of fluorescent pigment (a proxy for pollen) from plants experiencing decreased soil moisture. These findings suggest that the transfer of lower‐quality pollen from plants experiencing soil‐moisture limitation led to drought‐induced pollen limitation. Similar effects may occur in a wide variety of flowering plant species as climate warming and drought increasingly impact animal‐pollinated systems.