The seed productivity of the artichoke varieties Green Gold, Imperial Star, Violetto was revealed in the conditions of medium saline soils of the Bukhara region. The data obtained showed that seed productivity is dire...The seed productivity of the artichoke varieties Green Gold, Imperial Star, Violetto was revealed in the conditions of medium saline soils of the Bukhara region. The data obtained showed that seed productivity is directly proportional to fruit crowns. The soil and climatic conditions of the studied area significantly affect the ontogeny of varieties.展开更多
Pollen limitation of plant reproduction occurs across Angiosperms, particularly those in patched habitats We investigated the, relationship between pollen limitation and patch variables （patch size, visitation freque...Pollen limitation of plant reproduction occurs across Angiosperms, particularly those in patched habitats We investigated the, relationship between pollen limitation and patch variables （patch size, visitation frequency） in the desert plant Hedysarum scoparium （Fabaceae）, which is an important xerophyte in the arid and semi-arid regions of Northwest China and can grow well as a pioneer plant in shifting sand dunes. We observed insect visitation to H. scoparium over two flowering seasons and estimated pollen limitation using fruit set and seed production. Our results indicate that fruit set and seed production increased significantly with pollen supplementation compared with open pollination. Hedysarum scoparium was pollinated by over 8 species of bees, with 88.4% of visits made by introduced honeybees （Apis mellifera）. Bee visitation varied significantly among the patches of habitats, but not associated with patch size of habitat. In general, pollen limitation occurred more strongly during fruit set than during seed production. The patches that received higher rates of pollinator visits were less pollen limited for fruit set. Pollen limitation for seed production, however, was not associated with pollinator visitation frequency. We conclude that pollen limitation in H. scoparium was caused by more than one reason, not just pollinator visits.展开更多
Theory suggests that with sufficient environmental variation, pollen limitation might be observed at some places or times, and resource limitation at others, but there are no empirical data about the effect of seasona...Theory suggests that with sufficient environmental variation, pollen limitation might be observed at some places or times, and resource limitation at others, but there are no empirical data about the effect of seasonal change on the variation of pollen limitation and resource limitation within a flowering season. In this study, we examined pollen and resource limi- tation by comparing fruit set and seed production in natural- and hand-pollinated Hedysarum scoparium flowers in the middle reaches of the Hexi Corridor region, China, in 2010. We also described a role for the first substantial autumn rainfall in mediating a shift between pollen and resource limitation in H. scoparium, but did not analyze this experimentally Our results indicated that H. scoparium was resource limited at peak flowering during the summer, and was pollen limited at peak flowering during the autumn. The seasonal change （summer to autumn） mediated the shift between pollen and resource limitations in H. scoparium. The shift timing depended on the date of the first autumn rainfall in 2010. Changes in the first substantial rainfall in autumn may affect fruiting of H. scoparium, thus affecting population persistence of this species and development/structure of the local ecosystem if such conditions persist.展开更多
Estimating tree fruit production is important for various purposes;however, no consensus has been established on which method is appropriate over different tree species. Here the aim of this study was to assess whethe...Estimating tree fruit production is important for various purposes;however, no consensus has been established on which method is appropriate over different tree species. Here the aim of this study was to assess whether the tree crop size of taxa with different fruit morphology could be accurately estimated using the visual survey method (VSM), taking into consideration errors due to the participation of different observers. Eight main tree species of temperate deciduous forests of Japan were used. Using a hierarchical Bayesian framework, the model parameters were estimated to convert the number of fruits counted by VSM to the fallen fruit density. The estimated model had a high accuracy for seven of the eight tree species. The trees of the outlier species had the smallest diameter and height, presumably resulting in false-positive errors. The model could be easily generalized for other species that were not tested in this study by adjusting the model parameters to the size of the unit used in the visual survey. The bias caused by errors depending on the observer (likely false-negatives) was not substantial. Thus, the generalized VSM proposed in this study should be useful to accurately estimate the crop size across various tree taxa with low workload.展开更多
文摘The seed productivity of the artichoke varieties Green Gold, Imperial Star, Violetto was revealed in the conditions of medium saline soils of the Bukhara region. The data obtained showed that seed productivity is directly proportional to fruit crowns. The soil and climatic conditions of the studied area significantly affect the ontogeny of varieties.
基金funded by the National Basic Research Program of China (2009CB421303)
文摘Pollen limitation of plant reproduction occurs across Angiosperms, particularly those in patched habitats We investigated the, relationship between pollen limitation and patch variables （patch size, visitation frequency） in the desert plant Hedysarum scoparium （Fabaceae）, which is an important xerophyte in the arid and semi-arid regions of Northwest China and can grow well as a pioneer plant in shifting sand dunes. We observed insect visitation to H. scoparium over two flowering seasons and estimated pollen limitation using fruit set and seed production. Our results indicate that fruit set and seed production increased significantly with pollen supplementation compared with open pollination. Hedysarum scoparium was pollinated by over 8 species of bees, with 88.4% of visits made by introduced honeybees （Apis mellifera）. Bee visitation varied significantly among the patches of habitats, but not associated with patch size of habitat. In general, pollen limitation occurred more strongly during fruit set than during seed production. The patches that received higher rates of pollinator visits were less pollen limited for fruit set. Pollen limitation for seed production, however, was not associated with pollinator visitation frequency. We conclude that pollen limitation in H. scoparium was caused by more than one reason, not just pollinator visits.
基金funded by the National Natural Science Foundation of China (31400392,91025002,31370466)the Foundation for Excellent Youth Scholars of CAREERI,CAS (Y451111001)a General Financial Grant from the China Postdoctoral Science Foundation (2014M552516)
文摘Theory suggests that with sufficient environmental variation, pollen limitation might be observed at some places or times, and resource limitation at others, but there are no empirical data about the effect of seasonal change on the variation of pollen limitation and resource limitation within a flowering season. In this study, we examined pollen and resource limi- tation by comparing fruit set and seed production in natural- and hand-pollinated Hedysarum scoparium flowers in the middle reaches of the Hexi Corridor region, China, in 2010. We also described a role for the first substantial autumn rainfall in mediating a shift between pollen and resource limitation in H. scoparium, but did not analyze this experimentally Our results indicated that H. scoparium was resource limited at peak flowering during the summer, and was pollen limited at peak flowering during the autumn. The seasonal change （summer to autumn） mediated the shift between pollen and resource limitations in H. scoparium. The shift timing depended on the date of the first autumn rainfall in 2010. Changes in the first substantial rainfall in autumn may affect fruiting of H. scoparium, thus affecting population persistence of this species and development/structure of the local ecosystem if such conditions persist.
文摘Estimating tree fruit production is important for various purposes;however, no consensus has been established on which method is appropriate over different tree species. Here the aim of this study was to assess whether the tree crop size of taxa with different fruit morphology could be accurately estimated using the visual survey method (VSM), taking into consideration errors due to the participation of different observers. Eight main tree species of temperate deciduous forests of Japan were used. Using a hierarchical Bayesian framework, the model parameters were estimated to convert the number of fruits counted by VSM to the fallen fruit density. The estimated model had a high accuracy for seven of the eight tree species. The trees of the outlier species had the smallest diameter and height, presumably resulting in false-positive errors. The model could be easily generalized for other species that were not tested in this study by adjusting the model parameters to the size of the unit used in the visual survey. The bias caused by errors depending on the observer (likely false-negatives) was not substantial. Thus, the generalized VSM proposed in this study should be useful to accurately estimate the crop size across various tree taxa with low workload.
