Studies On Cold-Hardiness Mechanism And Protection Technology Of Seedlings During Hibernation Of Lamiophlomis Rotate (Benth.) Kudo

Lamiophlomis rotata (Benth.) Kudo is belong to labiate, and growing in Tibet plateau area at 3100⁵100m altitude from sea level, it's also called"dubutong"or"daba","dabuba"as Tibetan. The root, rhizome and the whole grass of it used as medicines could have effects of hemostasis, analgesia, promoting blood circulation, antisepsis and anti-inflammation, antitumor and enhancing immune system. It is caused by over-excavation in Endangered Species of wild resources, cultivation of artificial domestication of low winter survival rate. This study selected only one-year-old seedlings were used alone, using a combination of laboratory and field methods, by measuring the survival rate and physiological and biochemical indicators, designed to reveal the mechanism of its cold hardiness, overwintering protection of seedlings exploring its key technologies. The results are summarized as follows:1,From summer to early winter, the POD, SOD and CAT enzymes activity of Lamiophlomis rotata (Benth.) Kudo seedling were promoted, the soluble sugar content of crown in Lamiophlomis rotata (Benth.) Kudo seedling increased, the degree of membrane damaged was low and the accumulation of MDA was slow, but in the coldest month, those three enzymes'activity were decreased, the degree of membrane damaged was high and MDA accumulated to the maximum amount, all of the above responded the adaptive capacity of Lamiophlomis rotata (Benth.) Kudo seedling to low temperature stress, and it showed that the sensitivity of protective enzymes activity earlier than that of membrane permeability, and there were different response mechanism and adaptability of all the enzymes to low temperature stress.2,The Lamiophlomis rotata (Benth.) Kudo seedling had good adaptability to 0℃and above low temperature. The spray application of CaCl₂ could activated the antioxidant system in the seedling leaf of Lamiophlomis rotata (Benth.) Kudo, and the activation effect was increased with the increased concentration of spraying, but when the concentration was over 15 mmoL.L^-1, the activation effect was decreased significantly, and there's significant positive effect of spraying 15 mmoL.L^-1CaCl₂ on improving the cold resistance.3,The treatments of spraying 1.0⁷.5 mmoL.L^-1 SA could increase the protective enzymes activity, decrease membrane lipid peroxidation and membrane permeability, improve the cold resistance of Lamiophlomis rotata (Benth.) Kudo seedling. 7.5 mmoL.L^-1 and 5.0 mmoL.L^-1SA spraying the most significant effect.4,To carry out the drought resistance acclimation by mulching plastic film in the daytime, in night and all day in autumn could prolong the growth period of Lamiophlomis rotata (Benth.) Kudo, improve the true leaf grow-out rate and delay the turning-yellow period in autumn, and the results showed that treatments by mulching plastic film all day, in night and in the daytime delayed 16d, 8d and 6d respectively compared with the control.5,The overwintering rate is only 8.47% of Lamiophlomis rotata (Benth.) Kudo seedling under natural conditions, but by mulching plastic film, cattle manure and straw the overwintering rate could improve at different degree. In winter, the best treatment was by mulching plastic film, the overwintering rate increased by 50.60%⁵8.85% compared with the control, and the green stage ahead of time 13¹5d; the second treatment was by mulching cattle manure, the overwintering rate increased by 40.60%⁵3.49% compared with the control, and the green stage delayed 13¹5d; the treatment of mulching by straw has worse effect, the overwintering rate increased by 15.85%²1.87% compared with the control, and the green stage delayed 18²0d.