Effects Of Kcl On The Growth Of Catharanthus Roseus Flowering And The Alleviation Under Salt Stress

The effects of KCl on the biomass, the activities of SOD, CAT and POD enzymes, the TBARS content, the chlorophyll contents, the ion distribution, the chlorophyll fluorescence and the contents of vindoline, vincristine, catharanthine and vinblastine of C. roseus flowering were investigated using soil cultivation in greenhouse. The effects of KCl on the same experimental indicators of C. roseus flowering were also investigated under NaCl stress, in order to promote the growth and the alkaloid content accumulation of C. roseus under the normal condition and NaCl stress condition. The results were as follows:(1) When the KCl application was100mg·kg-1、200mg·kg-1and400mg·kg-1, the K+could promote the growth of C. roseus flowering. Compared with CK, the fresh mass and dry mass, the height of plants, the length of roots, the activities of SOD, CAT and POD enzymes were gradually increased and the TBARS content gradually decreasd. With the KCl application increasing, the Na+contents, the K+contents, the Cl-contents and the K+/Na+of the root, stem and leaves were also gradually increased. But when the KCl application was800mg·kg-1, the excessive K+could restrain the growth of C. roseus flowering. The fresh mass and dry mass, the height of plants, the length of roots began decrease and the TBARS content began increase. The K+contents and the Cl-contents of the root, stem and leaves went on increasing, but the Na+contents began decrease. So that the K+/Na+of the root, stem and leaves were significantly increased compared with the KCl application (400mg·kg-1), which making the ionic balance disturbance and restraining the growth of C. roseus.(2) When the KCl application was100mg·kg-1、200mg·kg-1and400mg·kg-1, the chla and chlb contents were gradually increased. The Fm, F0, Fv, Fv/Fm, Fv/F0,ΦPSⅡ, ETR and qp in the leaves were also gradually increased and the NPQ was gradually decreased with the KCl application increasing, which were good at photosynthesis. The alkaloid content was gradually increased with the KCl application increasing. But when the KCl application was800mg·kg-1, the photosynthesis indicators shown the opposite trend, and the excessive K+was not good for the growth of C. roseus flowering. In conclusion, the best growth and the contents of the four main alkaloids accumulation could merged when the KCl application was400mg·kg-1for C. roseus flowering, and the vindoline, vincristine, catharanthine and vinblastine contents were highest in all the experimental treatment,42.8、37.82、1.88and3.1mg·g-1, respectively.(3)When the Na+/K+was20:1(K2), KCl application could ease the negative impact of salt stress on C. roseus flowering. Compared with Kl, the fresh mass, the height of plants, the length of roots and the water content of C. roseus flowering were significantly increased and the TBARS content decreasd when the Na+/K+was20:1(K2). The activities of SOD, CAT and POD enzymes were significantly higher than the others when the Na+/K+is20:1. But the negative impact of salt stress was significantly increased when the Na+/K-is10:1(K3) and5:1(K4). Compared with CK, the Na+contents in the root, stem and leaves with Kl under NaCl stress were significantly increased, while the K+contents and the K+/Na+were decreased. With the KCl application increasing, the Na+contents of the root, stem and leaves with K2, K3and K4were gradually decreased, while the K+contents and the K+/Na+were gradually increased.(4) Compared with K1under3%o NaCl stress, the chlorophyll contents, Fm, F0, Fv/F0,ΦPSⅡ,ETR and qp in leaves were significantly increased and the NPQ was significantly decreased when the Na+/K+was K2. When the Na+/K+was K3and K4, the chlorophyll contents, Fm, Fv/F0, OPSII, ETR and qp of chlorophyll fluorescence parameters in leaves were significantly decreased, while the F0was significantly increased compared with K2. So that excessive KCl application could disserve the PSII system under NaCl stress. The vindoline, vincristine, catharanthine and vinblastine contents were highest when the Na+/K+is20:1,20.88,30.18,2.53and5.12mg·g-1, respectively. In conclusion, KCl application, when the Na+/K+was K2, could promote the growth for C. roseus flowering under salt stress by significantly relieving the negative impact of salt stress and maintaining the ion balance and photosynthesis, and inhance the contents of the four main alkaloids.