The stress phytohormone, abscisic acid （ABA）, plays important roles in facilitating plants to survive and grow well under a wide range of stress conditions. Previous gene expression studies mainly focused on plant r...The stress phytohormone, abscisic acid （ABA）, plays important roles in facilitating plants to survive and grow well under a wide range of stress conditions. Previous gene expression studies mainly focused on plant responses to short-term ABA treatment, but the effect of sustained ABA treatment and their difference are poorly studied. Here, we treated plants with ABA for 1 h or 9 d, and our genome-wide analysis indicated the differentially regulated genes under the two conditions were tremendously different. We analyzed other hormones＇ signaling changes by using their whole sets of known responsive genes as reporters and integrating feedback regulation of their biosynthesis. We found that, under short-term ABA treatment, signaling outputs of growth-promoting hormones, brassinosteroids and gibberellins, and a biotic stress-responsive hormone, jasmonic acid, were significantly inhibited, while auxin and ethylene signaling outputs were promoted. However, sustained ABA treatment repressed cytokinin and gibberellin signaling, but stimu- lated auxin signaling. Using several sets of hormone-related mutants, we found candidates in corresponding hormonal signaling pathways, including receptors or transcription regulators, are essential in responding to ABA. Our findings indicate interactions of ABA-dependent stress signals with hormones at different levels are involved in plants to survive under transient stress and to adapt to continuing stressful environments.展开更多
Understanding how ecological differences and anthropogenic disturbances synergistically drive population dynamics decline is critical for optimal management strategy definition. Main anthropogenic disturbances such as...Understanding how ecological differences and anthropogenic disturbances synergistically drive population dynamics decline is critical for optimal management strategy definition. Main anthropogenic disturbances such as habitat size reduction, fire and non-timber forest harvest affect demographic processes but our understanding of their interaction effects in contrasted ecological conditions is limited. We investigated the interaction effects of fruit harvest, fire, gallery forest size and distance to streambed on density, recruitment, survival and growth of Pentadesma butyracea offspring in dry and moist ecological conditions. We randomly selected in each ecological region six P. butyracea populations. We then established in each population, 10 subplots of 100 m2 within 1 ha to assess offspring demographic performance from 2015 to 2017. Results showed that fire suppressed the positive effect of large habitat size and amplified the negative effect of increasing local aridity on offspring growth. Fire and harvest synergistically reduced growth whereas offspring growth was resilient to fire in moist ecological region. Moist ecological conditions mitigated the negative effect of harvest on growth. Harvest mitigated the surprise negative effect of large habitat size on survival. However, in large gallery size, high harvest limited clonal recruitment and growth. There was a positive interaction effect between harvest and distance to streambed on survival (High harvest, Z = 2.045, p = 0.041, Medium, Z = 2.060, p = 0.039) but a negative interaction effect on growth (High, t = -2.357, p 0.05). Clonal offspring grew faster than sexual offspring in high harvest populations. In moist region, offspring survived better in large gallery forest size. In 2017, survival and growth were lower in large gallery forest. In 2017, offspring growth was higher near the riverbed where the survival rate low. This study suggests that management strategies should consider the interaction effects of anthropogenic disturbances and climatic condi展开更多
文摘The stress phytohormone, abscisic acid （ABA）, plays important roles in facilitating plants to survive and grow well under a wide range of stress conditions. Previous gene expression studies mainly focused on plant responses to short-term ABA treatment, but the effect of sustained ABA treatment and their difference are poorly studied. Here, we treated plants with ABA for 1 h or 9 d, and our genome-wide analysis indicated the differentially regulated genes under the two conditions were tremendously different. We analyzed other hormones＇ signaling changes by using their whole sets of known responsive genes as reporters and integrating feedback regulation of their biosynthesis. We found that, under short-term ABA treatment, signaling outputs of growth-promoting hormones, brassinosteroids and gibberellins, and a biotic stress-responsive hormone, jasmonic acid, were significantly inhibited, while auxin and ethylene signaling outputs were promoted. However, sustained ABA treatment repressed cytokinin and gibberellin signaling, but stimu- lated auxin signaling. Using several sets of hormone-related mutants, we found candidates in corresponding hormonal signaling pathways, including receptors or transcription regulators, are essential in responding to ABA. Our findings indicate interactions of ABA-dependent stress signals with hormones at different levels are involved in plants to survive under transient stress and to adapt to continuing stressful environments.
文摘Understanding how ecological differences and anthropogenic disturbances synergistically drive population dynamics decline is critical for optimal management strategy definition. Main anthropogenic disturbances such as habitat size reduction, fire and non-timber forest harvest affect demographic processes but our understanding of their interaction effects in contrasted ecological conditions is limited. We investigated the interaction effects of fruit harvest, fire, gallery forest size and distance to streambed on density, recruitment, survival and growth of Pentadesma butyracea offspring in dry and moist ecological conditions. We randomly selected in each ecological region six P. butyracea populations. We then established in each population, 10 subplots of 100 m2 within 1 ha to assess offspring demographic performance from 2015 to 2017. Results showed that fire suppressed the positive effect of large habitat size and amplified the negative effect of increasing local aridity on offspring growth. Fire and harvest synergistically reduced growth whereas offspring growth was resilient to fire in moist ecological region. Moist ecological conditions mitigated the negative effect of harvest on growth. Harvest mitigated the surprise negative effect of large habitat size on survival. However, in large gallery size, high harvest limited clonal recruitment and growth. There was a positive interaction effect between harvest and distance to streambed on survival (High harvest, Z = 2.045, p = 0.041, Medium, Z = 2.060, p = 0.039) but a negative interaction effect on growth (High, t = -2.357, p 0.05). Clonal offspring grew faster than sexual offspring in high harvest populations. In moist region, offspring survived better in large gallery forest size. In 2017, survival and growth were lower in large gallery forest. In 2017, offspring growth was higher near the riverbed where the survival rate low. This study suggests that management strategies should consider the interaction effects of anthropogenic disturbances and climatic condi
