The Research Of Water Stress On Three Kinds Of Sedum Plants Such As Sedum. Lineare Cv. ’jin Ye’,Etc

In this paper three species of sedum plants are chosen for researching:Sedum. lineare cv.’Jin Ye’、Triarrhena lutarioriparia and Iris germanica. Depending on controlling the moisture content in soil, six groups which contained moisture gradients get set. In each group some indicators of three sedum plants, which all exist under water stress, are measured and analyzed:relative conductivity, RWC and RWD, relative chlorophyll content, chlorophyll fluorescence parameters and plant morphological characteristics. And then the recovery test is also designed. From all test mentioned in this paper the water stress test was divided into waterlogged stress and drought stress, and the main conclusions are as follows:(1) Relative conductivityWith the aggravation of flooding and drought stress, relative conductivity of three plants rose in varying degree, Among these three plants, relative conductivity of Sedum. lineare cv.’Jin Ye’ and Triarrhena lutarioriparia rose on a large scale.(2) RWC and RWDFlooding Stress:With the aggravation of water logging stress, the RWC in leaves of Sedum. lineare cv.’Jin Ye’ had no significant changes. The RWC of Triarrhena lutarioriparia declined and of Iris germanica had a slight increase.Drought Stress:With the aggravation of drought Stress, RWC of three plants had all significantly decreased. Triarrhena lutarioriparia and Iris germanica decreased to a great extent compared to Sedum. lineare cv.’Jin Ye’.(3) Relative chlorophyll contentFlooding Stress:With the aggravation of water logging stress, the relative chlorophyll content of Sedum. lineare cv.’Jin Ye’ and Iris germanica had significantly decreased, and of Triarrhena lutarioriparia increased to some extent.Drought Stress:With the aggravation of drought stress, relative chlorophyll content of three kinds of plants have significantly decreased, including great declining content of Iris germanica, small declining content of other two Sedum plants.(4) Chlorophyll fluorescence parametersFlooding Stress:With the aggravation of water logging stress, the Fv/Fm of Sedum. lineare cv.’Jin Ye’ declined slightly, and there is no significant change in other two species. The Fv’/Fm’ of Sedum. lineare cv.’Jin Ye’ decreased significantly, and other two species had a slight decline. The qP of the three kinds of plant had decline. The ETR of Sedum. lineare cv.’Jin Ye’ had a significant decline, but Iris germanica have a mild decline, and Triarrhena lutarioriparia had no significant change.Drought Stress:With the aggravation of drought stress, the Fv/Fm、Fv’/Fm’、 qP、ETR of three kinds of plant had significant decline. Among them, the Fv/Fm、 Fv’/Fm’ of Iris germanica had a great decline. The qP、ETR of Triarrhena lutarioriparia and Iris germanica decreased much compared to the values changing of Sedum. lineare cv.’Jin Ye’.(5) External morphologyFlooding Stress:With the aggravation of waterlogging stress, the leaves of three kinds of plant turned to white or yellow, and leaves came to malaise and drop.Drought Stress:With the aggravation of drought stress, leaves of Iris germanica turned to thin, small, tarnish, drop and dry stems in sequence. Leaves of Sedum. lineare cv.’Jin Ye’ and Triarrhena lutarioriparia turned to thin,small,tarnish and stems dropping orderly.(6) Recovery testFlooding Stress:The Sedum. lineare cv.’Jin Fe’ and Triarrhena lutarioriparia grew new sprouts from the bottom. Iris germanica also grew new sprouts, but yellow leaves still exist.Drought Stress:After watering for two days, the Sedum. lineare cv.’Jin Ye’ and Triarrhena lutarioriparia recovered significantly, and leaves of them turned to thick, curl abating and luster. Iris germanica grew new sprouts after watering.(7) The stress tolerance ability to water logging of three kinds of plant are:Iris germanica> Triarrhena lutarioriparia> Sedum. lineare cv.’Jin Ye’. The stress tolerance ability to drought of three kinds of plant are:Sedum. lineare cv.’Jin Ye’> Triarrhena lutarioriparia>Iris germanica.