Effects Of Exogenous Phenolic Acid On The Leaves Photosynthetics And Roots Physiology Metabolism Of Strawberry

Phenolic acids is a class of important allelochemicals that caused strawberries continuous cropping obstacle problem in greenhouse culture. Clear the cause of continuous cropping obstacle phenolic acid type, content of space-time change rule. Adding exogenous phenolic acids on the influence of strawberry plant photosynthesis and root physiological metabolism. For further mechanism research and continuous cropping obstacle in strawberry that how to effectively control have important guiding significance. Therefore. The soil samples of different fixed number years of the continuous cropping plot for the material in Dandong city of Liaoning province. Using high performance liquid chromatographic (HPLC) technique, the strawberry rhizosphere soil types and phenolic acid content changes, different kinds and concentrations of phenolic acid strength. Using potted experiment, phenolic acid on strawberry plants growth, photosynthetic efficiency and metabolic effects of roots. The experimental results showed that in the strawberry rhizosphere separated and identified four main phenolic acids, phthalic acid,4-hydroxy benzoic acid, syringic acid and vanillic acid, and found that the longer the length of continuous cropping, the more the content of phenolic acids, but the phenolic acids species between the interannual change is not obvious. Thus it can be seen that phenolic acids content along with the increasing length of continuous cropping of accumulative trend, but species did not change obviously.Using potted experiment to explore the allelopathic effect of four kinds of phenolic acid strength, Through to explore the strawberry plant growth, photosynthetic efficiency and the efficiency of electron transfer, At low concentration 1.0 μg·g-1) the syringic acid and phthalic acid of strawberry plants to plant height, stem diameter, leaf area and growth indicators have promote role, When the concentration increases to 9.0 μg·g-1, the above ground dry weight and fresh weight of plant decreased significantly compared with control (CK), showed obvious inhibition, syringic acid and phthalic acid inhibitory effect than 4-hydroxy benzoic acid and vanillic acid. When the four phenolic acids concentration reaches 27.0 μg·g-1, clove acid and phthalic acid plant height was reduced by 46.06% and 46.06% respectively, and compared with the controls showed obvious inhibitory effect.The results showed that the allelopathic effects of syringic acid and phthalic acid stronger than 4-hydroxy acid and vanillic acid, speculated that the two may be the main phenolic acids in strawberry continuous cropping obstacle of allelochemicals.As the syringic acid and phthalic acid concentration increases, the strawberry leaf chlorophyll a and chlorophyll b appeared a trend of reducing the rise first, In the concentration of 1.0 μg·g-1, content of chlorophyll a and chlorophyll b, but carotenoid content that there was no obvious change, but with the increase of concentration, chlorophyll a and chlorophyll b and chlorophyll a/b values change. Experiment showed that phenolic acid treatment can change the strawberry leaf chlorophyll content of each component.Two kinds of phenolic acids can impact the stomatal conductance (Gs), intercellular CO2 concentration (Ci), net photosynthetic rate (Pn) and water use efficiency (WUE) on the blades of light of the whole system function has a certain influence. As the syringe acid and phthalic acid concentration increases, reflect the complex PSII put oxygen index (Wk) a straight line rise, relative variable fluorescence (Vj) was also significantly higher than that of control, and growth is greater than Wk, a side of photosynthetic electron donor and receptor side are serious damage, lateral inhibition degree is greater than the donor side reaction center receptors,820 nm light reflex curve deformated. The results showed that phenolic acid treatment in PSI and PSII activity dropped substantially, the two optical system coordination is damaged, thus affecting the normal transfer of photosynthetic electron in optical system, eventually weakened the efficiency of photosynthetic electron transfer.Exogenous add a high concentration of syringe acid and phthalic acid, the root of the activity of SOD, POD and CAT decreased, reduces the plant cell SOD, POD, CAT enzyme activities,making it weakened the ability of scavenging free radicals,O2-,H2O2 and malondialdehyde (MDA) accumulated, Excess free radicals control MPTP related proteins in the mitochondria of thiol was oxidized into disulfide bond, prompting MPTP opening, cause cytochrome c (Cyt c) from off on mitochondrial membrane, and then through the mitochondrial membrane into the cytoplasm, which reduces the Cyt c/a ratio and also may make the unsaturated fatty acid in the mitochondrial membrane peroxidation, resulting in reduced mitochondrial membrane fluidity, the integrity of the mitochondria, that affected the function of the mitochondria.