Genetic variation in yield under hot ambient temperatures spotlights a role for cytokinin in protection of developing floral primordia |
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Authors: | NAHUM NAVE DINESH KAFLE MARTIN HEGELE RINA KAMINETSKY JENS N WÜNSCHE ALON SAMACH |
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Institution: | 1. The Institute for Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, , Rehovot, 76100 Israel;2. Institute of Crop Science, Section Crop Physiology of Specialty Crops, Hohenheim University, , Stuttgart, D‐70599 Germany;3. Institute of Plant Science, ARO, The Volcani Center, , Bet Dagan, 50250 Israel |
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Abstract: | Unusually hot ambient temperatures (HAT) can cause pre‐anthesis abortion of flowers in many diverse species, limiting crop production. This limitation is becoming more substantial with climate change. Flower primordia of passion fruit (Passiflora edulis Sims) vines exposed to HAT summers, normally abort. Flower abortion can also be triggered by gibberellin application. We screened for, and identified a genotype capable of reaching anthesis during summer as well as controlled HAT conditions, and also more resistant to gibberellin. Leaves of this genotype contained higher levels of endogenous cytokinin. We investigated a possible connection between higher cytokinin levels and response to gibberellin. Indeed, the effects of gibberellin application were partially suppressed in plants pretreated with cytokinin. Can higher cytokinin levels protect flowers from aborting under HAT conditions? In passion fruit, flowers at a specific stage showed more resistance in response to HAT after cytokinin application. We further tested this hypothesis in Arabidopsis. Transgenic lines with high or low cytokinin levels and cytokinin applications to wild‐type plants supported a protective role for cytokinin on developing flowers exposed to HAT. Such findings may have important implications in future breeding programmes as well as field application of growth regulators. |
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Keywords: | Arabidopsis Passiflora edulis flower development gibberellins natural variation off‐season flowering plastochron |
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