Study On Physiological Response And Shade Tolerance Of Three Species Of Aglaonema Commutatun To Low Light Stress

In order to study the tolerance and adaptation mechanism of three species of Cotyledon to low light stress,three species of Cotyledon Aglaonema commutatun’Big Apple’,’Red Valentine’ and ’A.Lipstick’ were used as materials.Seven weak light gradients,A0(200 μmol·m-2·s-1),A1(100 μmol·m-2·s-1),A2(60μmol·m-2·s-1),A3(40μmol·m-2·s-1),A4(20μmol·m-2·s-1),A5(10 μmol·m-2·s-1),and A6(2μmol·m-2·s-1),were measured.The leaf color,chlorophyll fluorescence parameters,physiological and biochemical indexes were studied under low light,and the principal component analysis and subordinate function analysis were carried out.The results are as follows:1.There are different changes in leaf color,leaf shape and leaf amount among the three species.The morphology of the three species changes under the illumination of 40-100 μmol·m-2·s-1,under 2-10 μmol·m-2·s-1 illumination,the leaves will shrink,the color of the leaves will become dim,and the leaf amount will also decrease.The results showed that the parameters of L*,A*and B*of Aglaonema commutatun’A.Lipstick and ’Big Apple’ were higher at 40-100 μmol·m-2·s-1,and the two Aglaonema commutatun well,their leaves were red and bright,and their leaf color was excellent,Aglaonema ’red valentine’ is red at this time more bright,green parts of the light.Under the light intensity of 2-20 μmol·m-2·s-1,the morphology of the three plants was not good.2.The physiological effects of the three species of Aglaonema plants under weak light environment for 50 days.With the decrease of light intensity,the Aglaonema commutatun ’Big Apple’ Fo increased,the Fv/Fm,qP,ETR,SS,SP,SOD values showed a trend of first rising and then falling,the Chla+b,carotenoid content,electrical conductivity,and water content showed a trend of first falling and then rising,and the MDA first fell and then rising and then falling.The Fo value of Aglaonema commutatun ’A.Lipstick’,qP decreased,Fv/Fm,ETR,SS,SP,conductivity,and relative water content of leaves first rose and then fell,Chla+b first fell and then rose,carotenoids,MDA,and SOD first fell and then rose and then fell.The electrical conductivity,Fo and leaf relative water content of Aglaonema commutatun ’red valentine’ decreased first and then increased,Fv/Fm,qP,ETR,SS,SP,SOD and MDA increased first and then decreased,and the content of Chla+b and carotenoid increased.3.By principal component analysis,the optimum light environment and tolerance range of the three Aglaonema commutatun were obtained.The optimum light environment of the Aglaonema commutatun’Big Apple’ and ’Red Valentine’ was about 60μmol·m-2·s-1,under 40-100 μmol·m-2·s-1 light condition,it was more suitable.Under 200 μmol·mi-2·s-1 and 20 μmol·m-2·s-1 light condition,the leaf color of Aglaonema commutatun ’Big Apple’ was slightly lower,and under 200 μmol·m-2·s-1 light condition,it was unfavorable to the growth of Aglaonema commutatun ’red valentine’,under 2μmol·m-2·s-1 light,the growth ofall three plants was unfavorable.The most suitable light environment for Aglaonema commutatun ’A.Lipstick’ was about 100 μmol·m-2.s-1,and the best was 40-200 μmol·m-2·s-1,under 20-10 μmol·m-2·s-1 illumination,plants could grow but their ornamental degree decreased.According to the comprehensive scores,the tolerance range of Aglaonema commutatun ’A.Lipstick’ was larger.4.Through the analysis of subordinate function and the comprehensive evaluation of the negative tolerance,the results showed that the negative tolerance from strong to weak was as follows:Aglaonema commutatun ’red valentine’>Aglaonema commutatun ’A.Lipstick’>Aglaonema commutatun ’Big Apple’,the average value of D value of membership function is 0.567,0.497,0.390 respectively.Pearson correlation analysis was performed between the negative tolerance coefficient and D value of 12 single indexes.The significant correlation indexes with negative tolerance were qP,ETR,FO,Fv/Fm,total chlorophyll content and electrical conductivity.In this study,the optimum light conditions and shade tolerance of three Aglaonema of Costus L.were determined,and the shade tolerance indexes were selected to simplify the Comprehensive Evaluation of Aglaonema,it provides a theoretical reference for the cultivation,conservation and landscape application of the plants in the future.