The Research On The Effect Of Water Stress On The Physiology And Growth Of 3 Plants

Alchornea davidii,Laurocerasus hypotricha,Ardisia crenata are native plants wh-ich have a strong ornamental and adaptability.In order to make clear the influence of water on them,and the better use in the garden,this paper was writtened to studie s the influence of different moisture gradient on them.The total chloro-phyll content(Chi),malondialdehyde(MDA),soluble sugar(SS),soluble protein(SP),chlorophyll fluorescence parameters,light curve parameters and external morpholog-y were measu red.The results are as follows:(1)Effect of water on the Alchornea davidii:The same trend of flooding group(t-he soil moisture content was about 85%)and slight drought stress group(the soil m-oisture content was between20%-30%),the specific performance of the content of M DA increased first and then decreased,the total chlorophyll content decreased,while t-he other fluorescence parameters and photosynthetic rate are increased after the first d-ecreased;The change of each index in the extreme drought group(the soil moisture content was about 10%)was continuous,except for the continuous increase of the M DA content,the other values were continuous decreased,the growth of plants is serio-usly damaged;The leaves of Alchornea davidii are wilting,yellowing and drop phenol-menon;The extreme drought group died 35 days after the experiment.We can draw a conclusion:Alchornea davidii had strong resistance ability to wat-er,drought resistance,and the submergence tolerance ability is stronger than drought tolerance.Slight drought and flooding conditions are suitable for Alchornea davidii gro-wth.Be able to withstand 40 days of flooding,which will be fully restored under ce-rtain damage;Able to endure 40 days of mild drought and 30 days of extreme droug-ht.Alchornea davidii can be used in low-lying water or shore,with no problem in a 1-ittle humidity.With longtime stress,the leaves may be falled which affecting the lan-dscape,not affect its growth.It can grow normally under mild drought conditions,b-ut it is not recommended to last more than 30 days,Extreme drought conditions can also be grown for 15 days without affecting the landscape effect.Provide artificial irrig-ation measures is necessary to maintain the growth of production,in the case of wate-r supply in a timely manne.(2)Effect of water on the Laurocerasus hypotricha:In each group,the MDA con-tent in plants increased after water stress;The total chlorophyll content,soluble sugar content,soluble protein,fluorescence parameters and the maximum net photosynthetic rate were decreased;The Fv'/Fm',Fv/Fm,ETR,and Pmax of the slight drought treatm-ent group recovered and then declined after 15 days of stress;On the 4 day after be ing subjected to stress,the leaf of the water flooded group had the edge rot,chlorosis and the emergence of leaf falling.The flooded group died after 20 days' treatment.We can draw a conclusion:Laurocerasus hypotricha's ability of drought resistanc-e and waterlogging tolerance was not strong,and the ability of drought tolerance was stronger than the ability of submergence tolerance.Flooding and extreme drought are not suitable for the growth of Laurocerasus hypotricha,Only can endure 20 days of f-looding,mild drought for 25 days.Therefore,the only way to grow in the case of d-rought is not serious,and the need for regular replenishment.(3)Effect of water on the Ardisia crenata:The total chlorophyll content,soluble sugar content,soluble protein,and maximum net photosynthetic rate of the water floo-ded treatment showed a slow increase,and then decreased.However,the fluorescence parameters did not change much in the early stage,and finally increased and decrease-d with little change;The total chlorophyll content,soluble sugar content,soluble prot-ein,and maximum net photosynthetic rate of the first stage of extreme drought group increased slowly and then decreased,But the final value is littler.The values of fluor escence dynamic parameters were not changed much before the 30 day of treatment.After that,the values of each parameter began to decrease,and the decrease rate was larger;Slight drought group in the total chlorophyll,soluble sugar,soluble protein,ma-ximum net photo synthetic rate and chlorophyll fluorescence parameters of these values on the same trend,but the increase or decrease of the amplitude difference,The fina-1 values were similar to those of the control group,The total chlorophyll content wa-s higher than that of the control group at last;Leaf wilting and thinning occurred at t-he end of the 30 days with extreme drought group,Appearance of color change in F-looded group,There was no significant change in slight drought.We can draw a conclusion:Ardisia crenata had a certain degree of drought resistance and waterlogging resistance,and the ability of waterlogging tolerance was greater tha-n that of drought tolerance.Flooding and slight drought are suitable for Ardisia crenat a growth.Ardisia crenata can tolerate slight drought and extreme drought for 2 mont-hs.However,there was no obvious morphological change in plants with slight drough t.The extreme drought appeared wilting.According to the results of the experiment a nd the continuous observation of the water flooded group after the experiment,it is f-ound that the Ardisia crenata is able to withstand the long-term flooding.In order to the better application of Ardisia crenata in the garden,a month of extreme drought shuold be avoided,and the provide artificial irrigation measures is necessary.(4)The resistance of 3 kinds of plants were found by comparison,flooding-tolera nt ability:Ardisia crenata>Alchornea davidii>Laurocerasus hypotricha;drought res-istant ability:Ardisia crenata>Alchornea davidii>Laurocerasus hypotricha.