Abstract:

In this paper, changes of some physio-biochemical indexes in pine needles of approximate 20-year-old black pine (Pinus thunbergii) and masson pine (Pinus massoniana) were studied after pine wood nematode infection in the natural state. The results showed that after being infected, the water content in black pine and masson pine decreased with the disease development except at the early stage after infection. The changes in the chlorophyll and carotenoid content in the needles had the similar trends. The activities of antioxidant enzymes, catalase (CAT), superoxide (SOD) and peroxidase (POD), in the two pines were gradually decreased with the disease development, among which the decrease in the CAT activity was significant. The SOD activity slightly decreased, while the POD activity was increased at the early stage. It is concluded that chlorophyll, carotenoid and POD all played an important role in occurrence and development of pine wilt disease, and they took part in defense action and compensating action of the plants to the disease in initial infected phase.

Key words: Bursaphelenchus xylophilus, natural infection, water content, chlorophyll, carotenoid, antioxidant enzyme