The Effect Of Water Stress On Physiological-biochemical Characteristics Of Acer Palmatum Seedlings

To explore the influence of waterlogging stress and drought stress on the growth andphysiological characteristics of Acer palmatum, taking two-year-old seedlings of Acer palmatum astest materials. The test is simulated natural conditions of waterlogging stress and drought stressmeasurement and analysis of the main physiological and biochemical indicators in order topreliminary identification the waterlogging stress and drought stress resistance of Acer palmatum.The main results were as follows:Under waterlogging stress, the biomass of Acer palmatum seedlings increased in the early ofexperiment, was conducive to growth. With increasing of stress time, Acer palmatum seedlings’ therelative electrical conductivity of leaf increased and the relative water content of Acer palmatumseedlings decreased with small decline growth were inhibited. The root-shoot ratio of Acer palmatumseedlings decreased and leaves appeared etiolation. The content of photosynthetic pigment and the netphotosynthetic rate of Acer palmatum seedlings had been showing a downward trend. The netphotosynthetic rate was positive correlated with photosynthetic pigment, the relative electricalconductivity and the relative water content.Under waterlogging stress, MDA content decreased at first increased then and finally decreased,POD activity and SOD activity increased at first but later decreased. At the beginning of the stress,Acer palmatum seedlings produced the initial self-stress and relieved the stress brought about bystimulus. With a deeper level, stress hurt more than the self-protection system affect the normalgrowth of Acer palmatum seedlings. During the experiment, the treatment of LH decreased, thecontent declined slowly in the early, to the late tests decreased quickly, while soluble protein contentof the ZH treatment increased first but later decreased, may be the soluble protein and waterloggingstress resistance of different treatment or time Acer palmatum seedlings had some correlation underthe short-term stress. After soluble sugar content of Acer palmatum seedlings increased in the early,the change became complex. Indicating that soluble sugar have a role of osmotic on early stress ofAcer palmatum seedling. With the strengthening of persecution, the ability of regulation decreased.Under drought stress, with the decrease in relative water content of soil, the relative water contentof Acer palmatum seedlings decreased greatly and the relative electrical conductivity of leaf increased.The leaves appeared wilting, dying off and even death. The content of photosynthetic pigment, MDAcontent, POD and SOD activity decreased. The plant normal growth was affected by the stress. Thechanges of soluble protein content were so complex and accumulation was so few. These resultsindicate that the soluble protein on Acer palmatum seedlings did not have the osmotic effect. Underdrought stress conditions, at the beginning of experiments stomatal conductance decreased rapidlyafter the change of ups and downs.Early stomatal conductance decreased rapidly, later the change upsand downs. Acer palmatum seedlings photosynthetic capacity decreased. In the process of moisturestress, the water metabolism of Acer palmatum seedlings was not strong make the transpiration ratecontinued to decline. The results revealed that waterlogging stress and drought stress on Acer palmatum seedlingsgrowth and physiological-biochemical characteristics have a significant impact. The Acer palmatumseedlings’ ability of waterlogging and drought resistant was weak and can only adapt to short-termslightly waterlogging stress.