Effects Of Soil Water Deficit On Potted Peach Growth

The thesis studied the effects of soil water deficit on fruit setting ratio, shoot and fruit growth, leaf area, leaf water potential, photosynthetic rate, fruit total soluble and Epan 'coefficient during the different growing stages of three-year peach called "Wanmi". Data from experiments carried out in peach field were analyzed and the patterns of soil water potential variation described. Then the regularities of fruit setting ratio, shoot growth, fruit growth, leaf area, leaf water potential, photosynthetic rate and fruit total soluble under different soil water deficit treatments were analyzed. The relationships between soil water potential and leaf water potential, and those between leaf water potential and photosynthesis were studied. Moreover, the Epan coefficient of different treatments were computed and the reasons that affect the poted peach growth were described.The treatments were as follows: Treat 1 as full irrigation, Treat 2 water deficit to -200kPa during flowering stage, Treat 3 water deficit to -400kPa during flowering stage, Treat 4 RDI(regulated deficit irrigation) to -200kPa, Treat 5 RDI to -400kPa, Treat 6 RDI to -lOOkPa. The experimental results showed that fruit setting ratio, shoot and fruit growth, leaf area, leaf water potential, photosynthetic rate, fruit total soluble and Epan coefficient were affected by soil water deficit. Fruit setting ratio was related to soil water deficit, the severer soil water deficit the peach underwent, the less fruit setting ratio was. Shoot growth under soil water deficit was slower than that under full irrigation. Leaf area of Treat 2 and Treat 3 was smaller than that of other treatments and leaf area of Treat 3 was the smallest. The effects of soil water deficit on fruit growth were complex, the single fruit volume of Treat 3 was largest while that of Treat 1 was smallest. Because of the different fruit number each peach, the highest yield was at Treat 2, then at Treat 4. Leaf water potential variation was correlated to soil water deficit, the severer soil water deficit the peach suffered, the lower leaf water potential was and it went up later when full irrigation was applied. Photosynthesis had obvious "midday depress" and the severer soil water deficit the peach beard, the lower photosynthetic rate was. Fruit total soluble wasn't affected on Treat 2 and Treat 3 but was affected on Treat 4,Treatt 5 and Treat 6, fruit total soluble of Treat 5 was the highest. Epan coefficient changes had a pattern that it was low in April and early of May and was high in late of August and September, and it was lower during soil water deficit. Compare to that during full irrigation leaf water potential and soil water potential as well as leaf water potential and photosynthetic rate had same variation patterns, but leaf water potential had a delay to went up.