ハウス栽培におけるニホンナシ‘幸水’の果実発育と樹体生理について

Abstract

The fruit growth and physiological behavior of Japanese pear (Pyrus serotina Rehder) cv. Kosui under plastic were investigated. Treated trees were covered with ethlene vinylacetate film from 13th March to 20th May.The daily maximum temperature and soil temperature under plastic were 2-6°C and 1_??_2°C higher than those in the open field during the treatment period. Budbreak and flowering time were advanced by about 10 days due to a relatively high temperature.First harvest time was on 4th August under plastic and 17th August in the open field. Fruits grown under plastic with GA paste treatment were the largest in all treatments. Shape index (height/width) of the fruit grown under plastic was greater than that in the open field. Patterns of glucose and sorbitol accumulation in fruits grown under plastic were also different from those in the open field.Treated trees had 15% larger leaves and 22% longer shoots than those in the open field and leaf area indices (LAI) were 2.53 and 2.03, respectively. Carbohydrate content in current shoots grown under plastic was lower than that in the open field in autumn. The activities of root respiration under plastic were higher than those in the open field during summer season.