Salt Stress And Heavy Metal Stress On Growth And Physiological Processes Of Vetiver Impact

The experiment was carried out to determine the effects of NaC1 and heavy metal stress on growth and physiological process of vetiver grass, the results were as follows: 1. Leaf growth rate decreased with the aggravation of salt stress and heavy metal stress, but vetiver grass could still keep on growing. 2. Fv/Fm (the ratio of variable chlorophyll fluorescence to maximal chlorophyll fluorescence) was little affected by low concentration of NaCI and heavy metal, and a little affected by high 鑟ncentration of NaCI and heavy metal. 3. With the increase of NaCl concentration and the extension of treatment, Na~ concentration in vetiver grass increased, while K~ decreased, resulting in the increase of Na~/K~. Under low NaC1 concentration, Na~ concentration in shoot was lower than that in root, while it was as high as or even higher under high concentration of NaCl treatment. It showed that Na~ could transport from root to shoot and work as main osmotic adjustment ion. Vetiver grass had high ability of salt- tolerance., 4. ABA (abscisic acid) concentration in vetiver grass indreased with the increase of NaCI concentration and the extension of treatment. And ABA concentration in shoot was higher. than that in root. The increase of ABA concentration resulted in the enclosure of stomata in leaf. 5. The integrity of plasma membrane was affected by NaC1 stress, and the leaking percentage of electric conductivity?increased with the increase of NaC1 concentration and the extension of treatment. 2001 眫itiZ 44 6. With the increase of NaC1 concentration and the extension of treatment, anti-oxidative enzymes such as SOD, CAT and POD activities enhanced to reduce the damage of active oxygen. 7. Vetiver grass could absorb Pb, Zn, Fe, Cu efficiently in tailing. After growing in tailing for 50 days, the concentration of Pb, Zn, Fe and Cu in root of vetiver grass was 5201.Lg/g, 252OJ~g/g, 50501Ag/g and 7OiJgIg (based on dry weight) respectively, while the concentratin of Pb, Zn, Fe and Cu was relatively low, only l01.LgIg, 280~gIg, 290~Lg/g and 8.2~LgIg respectively. The ratio of Pb, Zn, Fe and Cu content in shoot to that in root was 0.0436, 0.252, 0.1301 and 0.2665 which showed that Cu and Zn had higher ability of transporting from root to shoot than Fe and Pb. 8. The dry matter accumulation in shoot and root of vetiver grass decreased with the aggravation of heavy metal stress. And dry weight of shoot was higher than that of root in all treatments. 9. With the aggravation of heavy metal stress and extention of stress, proline concentration increased accordingly, and proline concentration in root was higher than that in shoot because of higher heavy metal concentration in root than in shoot.