Populus 9 euramericana ‘‘Neva'' is the main poplar species in China, where drought stress is becoming extremely urgent. We carried out this research to study the effects of drought stress on the photosynthes...Populus 9 euramericana ‘‘Neva'' is the main poplar species in China, where drought stress is becoming extremely urgent. We carried out this research to study the effects of drought stress on the photosynthesis of Populus 9 euramericana ‘‘Neva''. Drought stress was induced by 58–62%(light), 48–52%(moderate), and 38–42%(severe) relative soil moisture content(RSMC). The effects of drought stress on photosynthetic rate, chlorophyll fluorescence parameters, and other related physiological parameters were investigated during treatment. Net photosynthetic rate(PN), and stomatal conductance decreased significantly and intercellular CO_2 concentration initially increased and then declined, whereas the stomatal limitation factors showed opposite trends in the light under moderate drought stress. Photosystem II(PSII) maximum photochemical efficiency, actual photochemical efficiency,and photochemical quenching decreased gradually under drought stress, whereas nonphotochemical quenching initially increased and then declined. Superoxide dismutase,peroxidase, and catalase activities initially increased and then decreased as RSMC was reduced, whereas malondialdehyde(MDA) content and relative electric conductivity(REC) increased gradually. These results suggest that stomatal factors accounted for the decline in PNunder light and moderate drought stress, whereas leaf PNdecreased mainly due to non-stomatal factors under severe drought stress. PSII was damaged; thus, photosynthetic electron transfer was restricted, indicating that heat dissipation is important for the light protection mechanism of plants.Antioxidant enzymes increased at the beginning of treatment, and the increased MDA and REC led to cell membrane damage. These results suggest that poplar seedlings stabilized their photosynthetic apparatus by reducing the light trapping ability under light and moderate drought stress conditions. This helped dissipate heat and enhance antioxidant enzyme activity. Stomatal factors accounted for the decline in P_N, whereas damage to PSII and antioxidant enzymes under severe drought stress suggested that the decline in P_N was caused by non-stomatal restrictive factors.展开更多
Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one ...Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one of the main obstacles to continuous cropping of Populus×euramericana ‘Neva’,we examined gene expression dynamics in Neva leaves induced by pHBA.The expression of genes related to photosynthesis and respiration changed,while mRNA involved in regulating gene expression during allelopathy was degraded.Some miRNAs that are involved in plant allelopathy target crucial genes for regulating reactive oxygen species.Moreover,coexpression regulatory networks were constructed based on profiles of the identified miRNA-target interactions and the differentially expressed miRNA-target pairs.These findings provide a mechanistic framework for understanding allelopathy in plants.展开更多
Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf ex...Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf explant with various concentrations and combinations of hormones are limited. Arabidopsis is a very useful model plant species for many aspects of plant biological study. Here, we reported a simple, fast and efficient one-step process for evaluating leaf explant-derived in vitro Arabidopsis organogenesis involving the application of various concentrations and combinations of exogenous hormones. The central portion of the fourth rosette leaf was harvested from the 21-days-old seedling and cultured in vitro on the media containing 216 combinations of exogenous hormones. Different types of organs, including roots, shoots, inflorescences, and leaf-like organs were initiated from leaf explants. Several optimal experimental combinations were selected. A hormone combination, 1.00 μM NAA + 10.00 μM ZT, was considered as the most efficient one for adventitious shoot regeneration. And for adventitious root regeneration, six hormone combinations, [(NAA + ZT: 1.00 + 0.10 μM;10.00 + 0.01 μM;20.00 + 0.10 μM;20.00 + 1.00 μM) and (NAA + 6-BA: 10.00 + 0.10 μM;20.00 + 10.00 μM)], were thought to be the best ones. Further, both auxin and cytokinin ratios and concentrations were crucial for efficient in vitro organogenesis. Our study provides the important information for hormone-regulated organogenesis.展开更多
基金financially supported by the National Public Welfare Industry Research Project of China(201504406)the National Natural Science Foundation of China(31770706)
文摘Populus 9 euramericana ‘‘Neva'' is the main poplar species in China, where drought stress is becoming extremely urgent. We carried out this research to study the effects of drought stress on the photosynthesis of Populus 9 euramericana ‘‘Neva''. Drought stress was induced by 58–62%(light), 48–52%(moderate), and 38–42%(severe) relative soil moisture content(RSMC). The effects of drought stress on photosynthetic rate, chlorophyll fluorescence parameters, and other related physiological parameters were investigated during treatment. Net photosynthetic rate(PN), and stomatal conductance decreased significantly and intercellular CO_2 concentration initially increased and then declined, whereas the stomatal limitation factors showed opposite trends in the light under moderate drought stress. Photosystem II(PSII) maximum photochemical efficiency, actual photochemical efficiency,and photochemical quenching decreased gradually under drought stress, whereas nonphotochemical quenching initially increased and then declined. Superoxide dismutase,peroxidase, and catalase activities initially increased and then decreased as RSMC was reduced, whereas malondialdehyde(MDA) content and relative electric conductivity(REC) increased gradually. These results suggest that stomatal factors accounted for the decline in PNunder light and moderate drought stress, whereas leaf PNdecreased mainly due to non-stomatal factors under severe drought stress. PSII was damaged; thus, photosynthetic electron transfer was restricted, indicating that heat dissipation is important for the light protection mechanism of plants.Antioxidant enzymes increased at the beginning of treatment, and the increased MDA and REC led to cell membrane damage. These results suggest that poplar seedlings stabilized their photosynthetic apparatus by reducing the light trapping ability under light and moderate drought stress conditions. This helped dissipate heat and enhance antioxidant enzyme activity. Stomatal factors accounted for the decline in P_N, whereas damage to PSII and antioxidant enzymes under severe drought stress suggested that the decline in P_N was caused by non-stomatal restrictive factors.
基金the National Public Welfare Industry Research Project of China(201504406)National Natural Science Foundation of China(31770706)+1 种基金National Natural Science Foundation of China(31870379)Science Research Projects of Facility Horticulture Laboratory of Universities in Shandong(2018YY031)。
文摘Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA)is one of the main obstacles to continuous cropping of Populus×euramericana ‘Neva’,we examined gene expression dynamics in Neva leaves induced by pHBA.The expression of genes related to photosynthesis and respiration changed,while mRNA involved in regulating gene expression during allelopathy was degraded.Some miRNAs that are involved in plant allelopathy target crucial genes for regulating reactive oxygen species.Moreover,coexpression regulatory networks were constructed based on profiles of the identified miRNA-target interactions and the differentially expressed miRNA-target pairs.These findings provide a mechanistic framework for understanding allelopathy in plants.
文摘Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf explant with various concentrations and combinations of hormones are limited. Arabidopsis is a very useful model plant species for many aspects of plant biological study. Here, we reported a simple, fast and efficient one-step process for evaluating leaf explant-derived in vitro Arabidopsis organogenesis involving the application of various concentrations and combinations of exogenous hormones. The central portion of the fourth rosette leaf was harvested from the 21-days-old seedling and cultured in vitro on the media containing 216 combinations of exogenous hormones. Different types of organs, including roots, shoots, inflorescences, and leaf-like organs were initiated from leaf explants. Several optimal experimental combinations were selected. A hormone combination, 1.00 μM NAA + 10.00 μM ZT, was considered as the most efficient one for adventitious shoot regeneration. And for adventitious root regeneration, six hormone combinations, [(NAA + ZT: 1.00 + 0.10 μM;10.00 + 0.01 μM;20.00 + 0.10 μM;20.00 + 1.00 μM) and (NAA + 6-BA: 10.00 + 0.10 μM;20.00 + 10.00 μM)], were thought to be the best ones. Further, both auxin and cytokinin ratios and concentrations were crucial for efficient in vitro organogenesis. Our study provides the important information for hormone-regulated organogenesis.
