| This experiment was conducted in 2013-2014 at Shandong Agricultural University. The pot experiment used two-year old Feicheng Peach trees [Prunus persica(L.)Batsch cv. Feicheng] grown in split-root pots, the root-zone treatments included 1/4, 2/4, 3/4 and 4/4 root-zone, to study the effects of different irrigation root-zone, irrigation volume and irrigation cycles on photosynthetic capacity and distribution of 13 C, 15 C. The field experiment used eleven-year old Feicheng Peach trees and conducted in 2014 at Feicheng Peach Research Institute. The field experiment included three different irrigation treatments, aimed to study the effects of different irrigation volume and irrigation cycles on photosynthetic capacity and fruit quality indexes. The main results were as follows:1. The pot experiment showed that, the net photosynthetic rate of each treatments tended to increase as the irrigation volume increased, and stabilized when the irrigation volume passed 2000 m L. However, transpiration rate continued to increase as the irrigation volume increased, and then the water use efficiency continually reduced. Among these treatments, 1/4-500 mL treatment had the lowest net photosynthetic rate, P16 treatment had the lowest water use efficiency, and P8 treatment had the relatively higher net photosynthetic rate and water use efficiency than the other treatments, the net photosynthetic rate of P8 treatment was 32.3% higher than 1/4-500 m L treatment and the water use efficiency of P8 treatment was 25.7% higher than P16 treatment. The results of the field experiment were similar to the pot experiment, the net photosynthetic rate of each treatments also tended to increase as the irrigation volume increased, and the net photosynthetic rate and water use efficiency of P30 and P45 treatments were higher than the other treatments. The pot experiment and field experiment all showed that, the chlorophyll fluorescence parameters included Fv/Fm, Fv’/Fm’, ΦPSⅡ and qP were all less affected by the irrigation treatments. Therefore, it was the irrigation volume rather than the root-zone or alternative cycles that affected the net photosynthetic rate, transpiration rate and water use efficiency of leaves. In conclusion, keeping an appropriately less irrigation volume and irrigating more times, could be conducive to reduce the transpiration rate and increase water use efficiency.2. The pot experiment showed that, the 1/4 and 2/4 root-zone irrigation treatments had higher distribution rate of 13 C in roots and sarcocarp but the distribution rate of 13 C in leaves and new shoots were lower, the distribution rate of 13 C in sarcocarp of 1/4-500 mL treatment was 143.6% higher than 4/4-500 m L treatment. Among the different alternative cycle treatments, the P8 treatment had the highest distribution rate of 13 C in roots and sarcocarp, and the lowest distribution rate of 13 C in new shoots, its distribution rate of 13 C in sarcocarp was 127.1% higher than P16 treatment. 1/2 root-zone irrigation treatment was conducive to promote the 13C-assimilate distributed to sarcocarp and inhibit the13C-assimilate distributed to new shoots, this may be caused by the drought stress in none irrigation root-zone, and the irrigation volume had a greater and direct impact on the distribution of 13 C, however, the irrigation cycles may affect the distribution of 13 C indirectly through controlling the drought stress in none irrigation root-zone.3. The pot experiment showed that, among these treatments, 16 d alternately treatment had the most irrigation volume and lower distribution rate of 15 N in sarcocarp but higher distribution rate of 15 N in leaves and new shoots. P4 treatment had the highest distribution rate of 15 N in sarcocarp but lower distribution rate of 15 N in leaves and new shoots, its distribution rate of 15 N in sarcocarp was 109.3% higher than P16 treatment. The partial root-zone irrigation treatments were conducive to promote the 15 N distributed to sarcocarp, the irrigation volume had a greater impact on the distribution of 15 N. Moreover, the 15 N use efficiency tended to increase as the root-zone and irrigation volume increased, but larger irrigation volume reduced the 15 N use efficiency. Among these treatments, 4/4-500 mL treatment had the highest 15 N use efficiency, its 15 N use efficiency was 172.5% higher than 1/4-500 m L treatment, and 30.4% higher than P16 treatment. However, the irrigation cycles had little impact on 15 N use efficiency. What’s more, using 1/2 root-zone alternative irrigation, keeping an appropriately less irrigation volume and irrigating more times, could be conducive to balance the distribution of nitrogen and promote more nitrogen distributed to sarcocarp.4. The field experiment showed that, at the mature stage, the proportion of sucrose to total soluble sugar was 78.6%~81.3%, sucrose was the major component of soluble sugar. Among the nine treatments, Q15, P30, P45 and C30 treatments had higher sucrose and total soluble sugar content, but all the treatments had little difference in acid components.(3Z)-3-Hexenyl Acetate,(2Z)-2-Hexenyl acetate, Hexyl acetate and γ-Decanolactone maybe the characteristic aroma components of red Feicheng Peach. What’s more, P45, C30 and Q15 treatments had higher fruit weight and soluble solid content, the fruit weight and soluble solid content of P45 treatment were namely 40.9% and 22.6% higher than P15 treatment, and specially P45 treatment could save 50% irrigation water and spent less labor. Moreover, using 1/2 root-zone alternative irrigation and irrigating 50~75mm at per 1/2 root-zone, the irrigation cycles in accordance with the soil moisture content, could be conducive to improve the soluble solid content and water use efficiency.5. The field experiment showed that, the change of nitrate nitrogen content in 0~20cm soil layer was consistent with the growth stages of Feicheng Peach. The nitrate nitrogen of Q45 treatment was leached to higher soil layer than the other treatments, its nitrate nitrogen content of 40~60cm and 60~80cm soil layer were significantly higher than the other treatments, however, the nitrate nitrogen content of other treatments had little difference. Moreover, the different irrigation treatments had little impact on ammonium nitrogen, total nitrogen and total phosphorus content. What’s more, the evapotranspiration of P treatment was significantly less than Q and C treatments, and the evapotranspiration of 15 d alternately treatment was significantly less than 30 d and 45 d alternately treatments. Among the nine treatments, Q45 treatment had the most evapotranspiration, and its evapotranspiration was 63.8% higher than P15 treatment. The irrigation volume had a greater impact on the evapotranspiration, keeping an appropriately less irrigation volume and irrigating more times could be conducive to reduce the evapotranspiration. Partial root-zone irrigation could also reduce the evapotranspiration owing to smaller irrigation area. |
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