| In order to establish the chemical regulation technology of cassava and provide its theoretical basis, this study designed three treatments of contrastive experiments on the base of having selected the most appropriate concentrations of IBA and choline chloride(CC) : (1) soaking the cuttings of seed stems w i th 50 mg L-1 IBA ; (2), spray i ng 300 mg L-1 CC on the leaves at the first expanding stage of tuber growth ; (3), soaking the cuttings of seed stems with 50 mg L-1 IBA + spraying 300 mg L-1 CC on the leaves at the first expanding stage of tuber growth, taking H2O as control. The research findings were presented briefly as follows.(1)The single and cooperative applications of IBA and CC all accelerated the photosynthesis of cassava, the sequence of such applications was IBA+CC>CC>IBA>CK.Compared with control, soaking the cuttings of seed stems with IBA increased the contents of Chla, Chl (a+b) and Car tosome extent, increased the Chlb content significantly and improved the values of Chla/Chlb and Chl /Car. Fo, Fm, Fv/Fm and Fv/Fo were all enhanced siightly while Tr, Gs, Ci and Pn were all accelerated significantly.Compared with control, spraying CC increased the contents of Chla, Chlb and Chl (a+b) significantly, increased the Car content alittle and so further improved the values of Chla/Chlb and Chl/Car. Fo, Fm, Fv/Fm and Fv/Fo were al enhanced to finite extent whi Ie Tr, Gs, Ci and Pn were all promoted significant Iy.Compared with control, the cooperative applicat ion of IBA and CC increased the contents of Chla, Chlb and Chl (a+b) significantly to a further extent, still increased the Car content siightly,but made the values of Chla/Chlb and Chl/Car more adapatable to high photosynthesis. Fo, Fm, Fv/Fm and Fv/Fo were all added more whi le Tr, Gs, Ci and Pn were all promoted most significantly.(2) The single and cooperative applications of IBA and CC all could increase the nutrient levels of cassava, the sequence of such applications was IBA+CC>CC>IBA>CK.Compared with control, soaking the cuttings of seed stems with IBA increased the total nitrogen, the soluble proteins and the soluble sugars in the leaves to a less significantextent. Spraying CC increased the total nitrogen, the soluble proteins and the soluble sugars in the leaves significantly. The cooperative application of IBA and CC could improved the total nitrogen, the soluble proteins and the soluble sugars in the leaves most significantly.The i ncrease of nutrient levels of cassava so obtained was related to the strengthening of photosynthesis, the increase in the number of green leaves and light-accepted leaf area and the prolonging time of photosynthesis.(3 ) The single and cooper ative applications of IBA and CC all could strengthen the stess-resistant potential.The sequence of such applications was IBA+CC>CC>IBA>CK.Compared with control, soaking the cuttings of seed stems with could restrain the relative leakage rate of electrolytes significantly, i ncrease the PO activity significantly, decrease the MDA content and advance the activities of anti-oxidized enzymes such as SOD, POD and CAT.Compared with control, spray ing CC could reduce the relative leakage rate of electrolytes and the MDA content significantly. At the same time, the activities of anti-oxidized enzymes such as SOD, POD, CAT and PO were improved significantly.Compared with control, the cooperative appiicat ion of IBA and CC could decrease the relative leakage rate of electrolytes and the MDA content significantly, increase the activities of SOD and CAT significantly and heighten the activities of POD and PO to most significantly extent.Meanwhile, the growing contents of non enzyme-catalyzed free radical removalists such as Car and Pro and the climbing concentrations of osmotic adjustment substances such as soluble sugars and proteins were also responsible for the strengthening stress-resistant potential of cassava.Such results proved that the cooperative application of IBA and CC had more effect than the single applications of IBA and CC o...
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