| Traditional plant protection focuses its attention on eliminating or controlling the population of biotic pests. Alternatively phytomedicine emphasizes the health-growing of its protecting plants, so to enhance their defensive and compensating abilities. That's closely comparable to the health protective medicine for human beings and animals.Applying pesticides in plants should be very careful in getting rid of their harmful effects on plants, because recent investigations proved that many pesticides may disturb the plant metabolism, and even make changing in plant components, even though without any injuring appearance. It is the problem of phytopharmacology almost ignored by plant-protectionists and pesticides chemists.The system of crop is open to outside and can maintain its inner steady. It is provided with academic significance to study how crop correspond the organism and apparatuses to maintain its inner steady under the levity environment, and it also have practical meaning for the growth and the yield of crop.Effects of pesticides on the physiology and biochemistry in different vegetable varieties were studied in this paper. The results were showed as follows:1 The effects of pesticides on the growth and development of vegetables The vegetables seedling height, root length and the quality of nutrition have been studied. The results showed that, pesticides have the inhibitory action to seedling growth, compared with the control, the seedling height reduces, and the root length decreases too. The uses of pesticides also have influence upon the quality of nutrition, e.g. protein content, solubility sugar content and Vc content.Effect of three pesticides on root stimulated luminescence (ICL) and super weak luminescence (SCL) were studied with bioluminescence technique. The results indicated that three pesticides all could stimulate root super weak luminescence of seedling, and the luminescence intensity increased proportionally to applied pesticide concentration; the root luminescence intensity after applying pesticides was lower than that of the comparison; the root length changed insignificantly during early period after applying pesticides, but strongly inhibited with the time of applied pesticides going. The result suggested that the effect of three pesticides on root of vegetable seedling has a sequence of Mancozeb > Dimethoate - Fenvalerate>deltamethrin, the higher concentration pesticide applied, the more serious effect on root tap were observed, and the sensitive of Brassica chinensis. L. variety was higher than that of Lactuca sativa Spp L. variety.2 The effects of three pesticides on the physiological and biochemical change of vegetablesEffects of three pesticides on MDA content and RMP in vegetable leaves have been studied. The result showed that, compares with the control, RMP have increased after treatment, and along with the time the RMP have increased more, the higher concentration of treatments, the more RMP increase; the MDA content shows the same trend as RMP.Effects of different dosages of pesticides on Chlorophyll content in vegetable leaves have been studied. The results indicated that compares with the control, the Chlorophyll content decreased after treatments, and the higher concentration of treatments are, the more serious Chlorophyll content decreased.Effects of three pesticides on photosynthate export rate of vegetable leaves were studied with 14C. Dynamics data of photosynthetic of labeled vegetable functional leaves of different treatments were recorded with living plant nutrient detection instrument equipped with multi-probes through tracer method of radioactive nuclide. Compartment analysis model and mathematical equations were constructed with dynamics principle and method of analysis, calculating constant (K) of export rate. The result showed that export rate of photosynthetic of labeled leaf was reduced after treatments with pesticides. This effect was positively correlated with the decline of photosynthate export rate of the leaf and mainly attributed to the reduction of photosynthesis rate.Effects of three pesticides on the content of ATP in seedling roots were studied with bioluminescence technique. The result indicated that the content of ATP in seedling roots decreased after treatments, along with concentration of treatments enlarging, the decreasing extent of ATP content also increased. Under the same processing level, the ATP content of Brassica chinensis. L. decreased more than Lactuca sativa Spp L., which reflected the varying influence on energy condition of root in homogeneous intimidation on two vegetable varieties.3 The response of antioxidant enzymes to pesticides stress Effects of three pesticides on the SOD content in vegetable leaves were studied .The results showed that, the SOD activeness enhanced in 4～8 days after treatment, then declined in 8～12days, and brought back in 12～16 days. Brassica chinensis. L. is more sensitivity to pesticides than Lactuca sativa Spp L.; as the concentration of treatments enlarging, the SOD content increase faster, which do more harm to vegetable organism, the damage recover more slowly.The antioxidant enzymes could response to pesticides stress. Low concentration of pesticides increased the activity of POD and CAT, while the activities of enzymes were inhibited by higher concentration of three pesticides.All in all, when vegetable were in stress, they might stimulate the antioxidant system to maintain stabilization of the cell, but would be damaged while the stress was too severity. |
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