Abstract:

In order to explore the impact of exhaust pollution, the rubber trees of varieties ‘Yunyan 77-2’ planted near a brick factory were studied. 3 groups of rubber trees stand at distance 200 m, 400 m and 600 m separately in the downwind directions of the brick factory were investigated, including the leaf physiological and biochemical parameters and tree diameters. The results showed that the tree diameters of 3 groups at different distance intervals were obviously different (P<0.01) with a trend of 200 m<400 m<600 m, which indicated that the impact of brickyard exhaust emission on tree growth increased with the decrease of distance from pollution source. For physiological-biochemical characteristics, brickyard exhaust pollution led to the decrease of Chla and reduces of photosynthesis, photosynthetic products and soluble sugar, which could affect the growth of rubber trees. Meanwhile, the greatly increase of superoxide anion free radical (O2-) led to the start of protective enzyme systems and activity increase of peroxidase, superoxide dismutase (SOD) and catalase (CAT), which could eliminate or reduce the O2- harm to rubber tree leaves. Exhaust pollution also led to the increase of MDA and Pro, which played a significant role in the regulating cell osmotic potential and balancing conductivity. Generally, although the rubber tree itself could resist or tolerate pollution damage by starting its protection system to some extent, the brick factory emissions would inevitably has a serious impact on the growth of rubber trees and leaf normal physiological processes, resulting in the reduce of photosynthesis and photosynthetic products, and finally leading to the dwarf and slender of rubber trees.