Effects Of Water Stress And Rewatering On Physiological And Photosynthetic-Chlorophyll Fluorescence Characteristics Of Zoysia Japonica

Zoysia japonica is a kind of important lawn grass in our country and widely usedin urban green space and lawn planting. Drought is an important limited factoraffecting its growth for Zoysia japonica. The water stress have a tremendous impacton growth, physiological characteristics, photosynthetic and chlorophyll fluorescencecharacteristics of Zoysia japonica. But some studies have shown that waterdeficit sometimes not entirely negative effects. Plant will repair itself when it issubjected to moderate drought and rewatering, meansure it will grow normally oreven better under other factors of environment are invariable if we economize water.So we can discuss the effect on the growth of Zoysia japonica under different waterstress and rewatering by reaserching the changes of growth, physiologicalcharacteristics, photosynthesis and chlorophyll fluorescence characteristics.Using Zoysia japonica as experimental materials, using weighting method tocontrol the filed water level of all groups. All experimental materials were divided toCK, mild water stress, moderate water stress and severe water stress four groups andwere rewatering each treatment group after under water stress16days. The effect ofwater stress and rewatering on Zoysia japonica were studied by reaserching thechanges of growth, physiological characteristics, photosynthesis and chlorophyllfluorescence characteristics. The main results showed that:1. Compared with the CK group, water stress decreased the biomass under andabove ground of Zoysia japonica and the activities of peroxicase (POD) and catalase(CAT); increased the activities of superoxide dismutase (SOD) and the content ofmalondiadehyde (MDA) and proline (Pro). After rewatering, the activities ofantioxidant enzyme, the content of MDA and Pro of all treatment groups weregradually close to the CK group.2. Compared with the CK group, chla and chla+b content decreased, the chl bcontent had no rule change and chl a/b increased, then decreased under the waterstress. Water stress also decreased photosynthetic rate (Pn), stomatal conductance(Gs), intercellular CO2concentration (Ci) and transpiration rate (Tr) but enhanced the water use efficiency (WUE).After rewatering, all treatment groups’ chlorophyllcontent and photosynthetic characteristics (except WUE) increased. The WUEdecreased first, then gradually stabilized.3. Compared with the CK group, all treatment groups’ Fo and qN increased, Fm,Fv, Fv/Fm, Fv/Fo, ΦPSII, ETR and qP decreased under water stress. All chlorophyllfluorescence characteristics had varying degrees of recovery of all treatment groupsafter rewatering.From the test data we can draw follow conclusions: the mild water stress hadlittle effect on growth of Zoysia japonica, but the severe water stress had seriousinjury for it during the water stress period. After rewatering all kinds ofcharacteristics of mild water stress group recovered good even better than the CKgroup, but the severe water stress group recovered slowly. So after mild water stressthen rewatering had positive effect on the growth of Zoysia japonica.