Influence of 2-(3,4 dichlorophenoxy)-triethylamine on photosynthesis of Phaseolus vulgaris L

Exogenous DCPTA Treatment Increases Mung Bean Yield by Improving Carbon Metabolism Pathway and Up-Regulating Photosynthetic Capacity and Antioxidants

Mung bean is characterized by having a good edible and medicinal value, while its flowers and pods have low production. Being a tertiary amine, DCPTA [2-(3,4-dichlorophenoxy) triethylamine] substantially regulates the growth and development of crops, maintaining production. Yet it is still limited in terms of the regulation of DCPTA on growth and development, including the yield and sugar metabolism of mung bean. In this study, DCPTA was sprayed at the beginning of mung flowering through a two-season cultivation, to assess its effects on the yield, leaf area per plant, plant height, seed setting rate, photosynthesis, chlorophyll content, and endogenous protective enzymes. Experimental results illustrated that relative to the control (CK), the DCPTA application significantly (p < 0.05) improved the yield of Bailv 11 mung bean, which rose to 6.9% in 2020 and 7.8% in 2021, respectively. This effect positively corresponded to a significant (p<0.05) increase in the number of pods and grains per plant and pod setting rate, but a non-significant difference in 1,000-grain weight. DCPA application also increased the area and fresh weight of leaf, mung height, and its organ dry weight (i.e., leaf, branch, and stem). During plant growth over DCPTA application, the increased activities of SOD, POD, and CAT improved the net photosynthetic rate, stomatal conductance, and transpiration. In addition, transcriptome sequencing further demonstrated that DCPTA treatment significantly (p < 0.05) up-regulated the sucrose synthase, invertase, and fructose kinase in all organs (i.e., leaves, pod skins, and grains) of the plant. In particular, this effect was much greater in the sucrose synthesis (i.e., sucrose content) in leaves. Our study, therefore, concludes that DCPTA application promotes the yield of mung bean via likely enhancing its photosynthetic capacity and sucrose synthase, fructokinase, and beta-fructofuranosidase expression regulation.

Exogenous 2-(3,4-Dichlorophenoxy) triethylamine alleviates salinity stress in maize by enhancing photosynthetic capacity, improving water status and maintaining K+/Na+ homeostasis

BACKGROUND

Soil salinity restricts plant growth and productivity. 2-(3,4-dichlorophenoxy) triethylamine (DCPTA) can alleviate salinity stress in plants. However, the mechanism of DCPTA-mediated salinity tolerance has not been fully clarified. We aimed to investigate its role in enhancing photosynthetic capacity, improving water status, maintaining K+/Na+ homeostasis and alleviating salinity stress in maize (Zea mays L.).

RESULTS

In present study, maize seedlings were grown in nutrient solutions with a combination of NaCl (0, 150 mM) and DCPTA (0, 20, 100, and 400 μM). And photosynthesis, water status, ion homeostasis and the expression of genes involved in ion uptake and transport were evaluated in the maize seedlings. The results demonstrated that DCPTA alleviated the growth inhibition of maize seedlings exposed to salinity stress by increasing the net photosynthetic rate (Pn) and the quantum efficiency of photosystem II (PSII) photochemistry. DCPTA improved the root hydraulic conductivity, which help maintained the water status. A relatively high K+ concentration but a relatively low Na+ concentration and the Na+/K+ ratio were observed in the presence of DCPTA under salinity stress. Additionally, DCPTA altered the expression of four genes (ZmSOS1, ZmHKT1, ZmNHX1 and ZmSKOR) that encode membrane transport proteins responsible for K+/Na+ homeostasis.

CONCLUSIONS

DCPTA improved the salinity tolerance of maize may be associated with enhanced photosynthetic capacity, maintenance of water status and altered expression of genes involved in ion uptake and transport.