Physiological Response Mechanism Of Leopard Skin Cutting Seedlings To Water And Fertilizer Stress

Litsea coreana var.lanuginosa belongs to Litsea's genus of Lauraceae's family plant,is a evergreen small tree plants,and it is the raw material plant of characteristic tea drink Laoying Tea which has high nutritional value and great market prospect in Guizhou province.To provide scientific basis for water and fertilizer management measures establishment of Litsea coreana cutting seedlings,the physiological and biochemical indexes and changes with 3 years old cutting seedlings as the research object under different drought and nutrient stress treatments were observed and compared,The main results were as follows.(1)The length and weight of fresh treetop,the dry weight of root,the number of first lateral roots and peroxidase(POD)decreased with the increase of drought stress,but the root activity increased with the increase of drought stress level,which had no effect on root activity ratio;The content of soluble sugar,protein and chlorophyll and the activity of catalase(CAT),superoxide dismutase(SOD)activity and malondialdehyde(MDA)increased first and then decreased with the increase of drought stress,they were both highest when the soil volumetric moisture content was 19.5%,however the content of total phenol was the highest when the soil volumetric moisture content was 29.2%;The activity of polyphenol oxidase(PPO)and free proline(Pro),the production rate of superoxide anion(O2-)increased with increasing drought stress.(2)The correlation of the physiological and biochemical indexes of Litsea coreana cutting seedlings showed that the soil volumetric moisture content was significant positively correlated with root activity,soluble sugar and Pro,and negatively correlated with the length and weight of fresh treetop,the dry weight of root,the number of first lateral roots,total phenol,chlorophyll,MDA and POD,but irrelevant with root activity ratio,protein,CAT,PPO,SOD and O2-.(3)The results of principal component analysis of drought stress analysis showed that the weight of fresh treetop,the dry weight of root,the content of protein and total phenol in the roots and soluble sugar in the leaves,chlorophyll,MDA and PPO were effected to adapt to drought environments.(4)Under different nutrition stress,Fe-lacked had significant effect on the weight of fresh treetop and the number of first lateral roots of Litsea coreana cutting seedlings;Lack of K,Ca and Mg had significant effects on root weight;any nutrient elements deficiencies would have significant effect on root activity,while had no significant effect on the root activity ratio,all above effects were inhibited.The descending order of lack of nutrient elements influenced the growth of Litsea coreana cutting seedlings were lack of Fe,Ca,N,K,P,Mg;Lack of N would promote POD increased;lack of P would promote the content of MDA;Lack of Ca could seriously inhibit the accumulation of nutrients,lack of Mg would inhibit the content of chlorophyll;Lack of Fe would promote the SOD activity;Lack of K,Ca,Mg and Fe had inhibitory effect on the activity of PPO;The content of Pro responded when lack of N,P,Ca,Mg;The absence of any element could inhibit O2-and CAT.The deficiency of P,K,Ca and Mg would inhibit the control effect of Litsea coreana cutting seedlings,and the descending order of inhibition effect were lack Mg,P,Ca,K,but lack of Fe and N would promote the control effect,and lack of Fe was greater than lack of N.(5)Under the results of principal component analysis of nutrition stress analysis,the comprehensive score of each treatment group was calculated and sequenced.The descending order were total,lack of P,K,Mg,N,Fe,Ca.However the descending order of different nutrition deficiency effects of physiological and biochemical on Litsea coreana cutting seedlings were lack of Ca,Fe,N,Mg,K,P.