Effect Of Matrix Moisture Changes On Fruit Quality Of Red Fuji Apple

With the progress of society and the development of national economy, water shortage situation was increasingly grim in China. As apple was one of fruit trees that required great water, water became an important factor that limited apple yield, quality and sustainable development. The effect of substrate moisture content changes on fruit quality of Red Fuji Apple was researched, which not only could contribute to further discussion of physiological effects of soil moisture to improve the quality of Red Fuji apple, but could provide theoretical basis for water-saving at proper time, reasonable irrigation amount and time in apple production.The effect of different matrix moisture treatment on fruit size, fruit water content, fruit hardness and physiological indexes including soluble sugar, pectin and pectin methylesterase in flesh and peel of potted Fuji apple was studied by setting 8 relative water content treatments in matrix. The main results were as follows:1. The effect of matrix moisture change on fruit size and weight of Red Fuji apple was obvious. The fruit size and weight increased by sharply raising matrix moisture from 50~55% and 65~70% to 80-85% (T2, T3, T4, T6, T7, T8). With matrix moisture maintaining 50~55%, the fruit size and weight declined.2. The water content in peel and pulp, fruit hardness and soluble solids content of Red Fuji apple were significantly influenced by matrix moisture changes. With matrix moisture keeping at the level of 50-55% and 65-70% (T1, T5), the fruit water content declined and fruit hardness and soluble solids content increased. With the matrix moisture in T2, T3, T4 increasing from 50-55% to 80-85% and in T6, T7, T8 increasing from 65-70% to 80-85% on 69d, 101d and 130d after full blossom respectively, the fruit water content increased, and fruit hardness and soluble solids content declined.3. The effect of matrix moisture change on total soluble sugar was obvious. With matrix moisture keeping at the level of 50-55% (T1), the total soluble sugar maintained a minimum level. While the total soluble sugar increased in other treatment.4. The matrix moisture change had little influence on total phenolic content in pulp, but obviously effected on total phenolic content in peel. With the matrix moisture in T2, T3, T4 increasing from 50-55% to 80-85% and in T6, T7, T8 increasing from 65-70% to 80-85% on 69d, 101d and 130d after full blossom respectively, the total phenolic content in peel was significantly lower than that in other treatment in the same period.5. The matrix moisture change had obvious effect on SOD, POD and PPO activity in fruit. There was significant difference in SOD, POD and PPO activity between the treatment with matrix moisture change (T2, T3, T4 and T6, T7, T8) and the treatment without matrix moisture change (T1, T5). Both the SOD activity and POD activity in pulp and peel increased first and decreased afterwards. PPO activity in peel decreased with matrix moisture change (T2, T3, T4 and T6, T7, T8). SOD activity reached maximum on 159d after full blossom in the treatment without matrix moisture change (T1, T5).6. The pectin content and pectin methylesterase activity in fruit were obviously affected by matrix moisture change. Water soluble pectin content of peel in the treatment with matrix moisture change (T2, T3, T4 and T6, T7, T8) was higher than that in the treatment without matrix moisture change (T1, T5). But water soluble pectin content of pulp and protopectin content of peel and pulp showed a contrary tendency. The pectin methylesterase represented the highest activity in T4 and T8, and the lowest in T1 and T5.7. The phenylalanine aminolyase activity (PAL) in fruit was obviously influenced by matrix moisture change. PAL in peel reached a maximum value on 129d after full blossom. PAL increased with matrix moisture increasing. PAL in pulp at every treatment had no obvious difference after the change of matrix moisture.