Photosynthetic Physiological Response to Drought Stress of Populus euphratica at Different Ages in Minqin

[Objectives]This study was conducted to investigate the photosynthetic physiological characteristics of Populus euphratica trees at different forest ages in the desert area of Minqin in response to drought stress.[Methods]With P.euphratica trees of different ages in Minqin as the research object,the water characteristics and photosynthetic physiological indexes(chlorophyll,soluble sugar,POD,SOD and MDA)were compared under different conditions.[Results]On the time gradient,the soil water contents of P.euphratica of different ages decreased continuously with the extension of irrigation stop time,but the decreases were small.Under the same stress treatment,the soil water contents of P.euphratica of different ages increased with the deepening of soil layer,but the differences were not significant(P>0.05).Under normal condition,the chlorophyll contents of P.euphratica at three ages gradually increased with the increase of age.The chlorophyll contents in leaves of P.euphratica at different ages were all lower under normal condition and higher under water stress.The changes of POD and SOD activity in leaves of P.euphratica at different ages under different conditions were basically the same,showing that the enzyme activity was higher under water stress than under normal under.The MDA contents in leaves of the young and middle P.euphratica forests were higher under water stress at 7 and 21 d than under normal condition,and the differences were not significant(P>0.05);and the MDA content in leaves of the mature P.euphratica forest was higher under water stress at 21 and 35 d than under normal condition.Drought stress has a certain effect on the photosynthetic physiological characteristics of P.euphratica.In summary,under drought stress,the chlorophyll content,SOD and POD activity,and MDA molar concentration in the leaves of P.euphratica were basically higher than under normal condition,indicating that P.euphratica could resist drought environment through osmotic adjustment and showed strong drought resistance.[Conclusions]This study provides a theoretical reference for the restoration,protection and reconstruction of natural P.euphratica forests in the desert area of Minqin.

QTL analysis of leaf photosynthetic rate and related physiological traits in rice(Oryza sativa L.)

Photosynthesis is one of the most important factors that influence the biomass and yield. Recently, more attention has been paid to genetic study on rice photosynthesis and rice breeding for the physiological traits related to high efficient photosynthesis. Chlorophyll content, stomatal resistance, and transpiration rate were very important physiological traits related to photosynthesis. But until now, no genetic study on these traits has been reported. A DH population derived from anther culture of ZYQ8/JX17, a typical indica/japonica hybrid was developed,

Effects of Two Kinds of Arbuscular Mycorrhizal Fungi (AMF) Inoculums on Cucumber Seedlings Growth

To study the effects of AMF （ arbuscular mycorrhizal fungi） ineeulums on seedling growth of cucumber, vegetable seeds were inoculated with two kinds of AMF ineculums BF （ mycorrhiza for plants） and VT （ mycorrhiza for vegetables） from Czech Republic during sowing in trays in greenhouse. The root AMF infection rates in seedlings were 49.30% and 37.65% respectively after 35 d growth. The plant height, stem diameter, fresh and dry weight of those seedlings inoculated with BF and VT were higher than that in CK. Compared with the CK, VT inoculation significantly improved the root activity, chlorophyll content and photosynthetic rate of cucumber seedlings. Comprehensive analysis showed that VT could promote seedling growth of protected cucumber.

Integrated transcriptome and proteome analyses reveal potential mechanisms in Stipa breviflora underlying adaptation to grazing

Background:Long-term overgrazing has led to severe degradation of grasslands,posing a significant threat to the sustainable use of grassland resources.Methods:Based on the investigation of changes in functional traits and photosynthetic physiology of Stipa breviflora under no grazing,moderate grazing,and heavy grazing treatments,the changes in expression patterns of genes and proteins associated with different grazing intensities were assessed through integrative transcriptomic and proteomic analyses.Results:Differentially expressed genes and proteins were identified under different grazing intensities.They were mainly related to RNA processing,carbon metabolism,and secondary metabolite biosynthesis.These findings suggest that long-term grazing leads to molecular phenotypic plasticity,affecting various biological processes and metabolic pathways in S.breviflora.Correlation analysis revealed low correlation between the transcriptome and the proteome,indicating a large-scale regulation of gene expression at the posttranscriptional and translational levels during the response of S.breviflora to grazing.The expression profiles of key genes and proteins involved in photosynthesis and phenylpropanoid metabolism pathways suggested their synergistic response to grazing in S.breviflora.Conclusions:Our study provides insight into the adaptation mechanisms of S.breviflora to grazing and provides a scientific basis for the development of more efficient grassland protection and utilization practices.