Aims Drought stress and the degree of drought severity are predicted to rise under highly variable patterns of precipitation due to climate change,while the capacity of trees to cope with drought recovery through phys...Aims Drought stress and the degree of drought severity are predicted to rise under highly variable patterns of precipitation due to climate change,while the capacity of trees to cope with drought recovery through physiological and biochemical adjustment remains unclear.We aimed to examine the coupling of physiology and biochemistry in trees during drought and the following recovery.Methods Potted seedlings of Cinnamomum camphora were grown under well watered conditions prior to the experimental drought stress,which was initiated by withholding water.Seedlings were rewatered following attainment of two drought severities:mild drought(stomatal closure)and moderate drought(ψxylem=−1.5 MPa).We measured leaf-level water potential,gas exchange(photosynthesis and stomatal conductance),abscisic acid(ABA),proline and non-structural carbohydrates(NSCs)concentrations in seedlings of C.camphora during drought and a 4-day recovery.Important Findings We found that drought severity largely determined physiological and biochemical responses and affected the rate of recovery.Stomatal closure occurred at the mild drought stress,accompanied with ABA accumulation in leaves and decline in water potential,while leaf proline accumulation and variable NSC were evident at the moderate drought stress.More severe drought stress led to delayed recovery of gas exchange,but it did not have significant effect on water potential recovery.The relationships of water potential and gas exchange differed during drought stress and post-drought recovery.There was tight coupling between water potential and gas exchange during drought,but not during rewatering due to high ABA accumulation in leaves,thereby delaying recovery of stomatal conductance.Our results demonstrate that ABA could be an important factor in delaying the recovery of stomatal conductance following rewatering and after water potential recovery of C.camphora.Furthermore,greater drought severity had significant impacts on the rate of recovery of tree physiology and biochemistry.展开更多
RCAN1, also known as DSCR1, is an endogenous regulator of calcineurin, a serine/threonine protein phosphatase that plays a critical role in many physiological processes. In this report, we demonstrate that p38a MAP ki...RCAN1, also known as DSCR1, is an endogenous regulator of calcineurin, a serine/threonine protein phosphatase that plays a critical role in many physiological processes. In this report, we demonstrate that p38a MAP kinase can phosphorylate RCAN1 at multiple sites in vitro and show that phospho-RCAN1 is a good protein substrate for calcineurin. In addition, we found that unphosphorylated RCANI noncompetitively inhibits calcineurin protein phosphatase activity and that the phosphorylation of RCAN1 by p38a MAP kinase decreases the binding affinity of RCAN1 for calcineurin. These findings reveal the molecular mechanism by which p38a MAP kinase regulates the function of RCAN1/calcineurin through phosphorylation.展开更多
基金supported by grants from the National Natural Science Foundation of China(31600483,31760111,31901091)the Outstanding Young Scholar of Jiangxi Science and Technology Innovation(20192BCBL23016)the Jiangxi Provincial Department of Education(GJJ190945).
文摘Aims Drought stress and the degree of drought severity are predicted to rise under highly variable patterns of precipitation due to climate change,while the capacity of trees to cope with drought recovery through physiological and biochemical adjustment remains unclear.We aimed to examine the coupling of physiology and biochemistry in trees during drought and the following recovery.Methods Potted seedlings of Cinnamomum camphora were grown under well watered conditions prior to the experimental drought stress,which was initiated by withholding water.Seedlings were rewatered following attainment of two drought severities:mild drought(stomatal closure)and moderate drought(ψxylem=−1.5 MPa).We measured leaf-level water potential,gas exchange(photosynthesis and stomatal conductance),abscisic acid(ABA),proline and non-structural carbohydrates(NSCs)concentrations in seedlings of C.camphora during drought and a 4-day recovery.Important Findings We found that drought severity largely determined physiological and biochemical responses and affected the rate of recovery.Stomatal closure occurred at the mild drought stress,accompanied with ABA accumulation in leaves and decline in water potential,while leaf proline accumulation and variable NSC were evident at the moderate drought stress.More severe drought stress led to delayed recovery of gas exchange,but it did not have significant effect on water potential recovery.The relationships of water potential and gas exchange differed during drought stress and post-drought recovery.There was tight coupling between water potential and gas exchange during drought,but not during rewatering due to high ABA accumulation in leaves,thereby delaying recovery of stomatal conductance.Our results demonstrate that ABA could be an important factor in delaying the recovery of stomatal conductance following rewatering and after water potential recovery of C.camphora.Furthermore,greater drought severity had significant impacts on the rate of recovery of tree physiology and biochemistry.
基金supported in part by Ministry of Science and Technology of China (Grant 2011CB910803)
文摘RCAN1, also known as DSCR1, is an endogenous regulator of calcineurin, a serine/threonine protein phosphatase that plays a critical role in many physiological processes. In this report, we demonstrate that p38a MAP kinase can phosphorylate RCAN1 at multiple sites in vitro and show that phospho-RCAN1 is a good protein substrate for calcineurin. In addition, we found that unphosphorylated RCANI noncompetitively inhibits calcineurin protein phosphatase activity and that the phosphorylation of RCAN1 by p38a MAP kinase decreases the binding affinity of RCAN1 for calcineurin. These findings reveal the molecular mechanism by which p38a MAP kinase regulates the function of RCAN1/calcineurin through phosphorylation.
