弛下水位の高さによるブドウおよびナシの生育の差異-2-

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Influence of Ground Water Table on Growth of Grape (cv. Delaware) and Japanese Pear (cv. Nijisseiki) (II). N. NISHIMOTO, A. OYAIZU, T. NODA, M. OHNO and K. NAGASAWA, Faculty of Horticulture, Chiba University, Matsudo, Japan. Tech. Bull. Fac. Hort. Chiba Univ., No.21: 9-17, 1973. In continuation of a previous study, the effects of 3 different water table, 80cm (A), 50cm (B) and 20cm (C) under ground, on the tree growth, character of leaves and fruits in 2-year-old, pot-grown 'Delaware' grapes and 'Nijisseiki' pears were observed. In grapes, top growth of A and B plots was similar and growth of C plot plants was poorest when compared to that of other plots. In pears, especially top growth of C plot was much smaller than that of A and B plots. Leaf area of grapes grown in A plot was larger than that produced in C plot. Ratio of fallen leaves to total number of leaves in C plot plants reached 50, that was 2.6 times larger than that of A plot on Oct. 12. In pears, leaf area of A plot was larger than that in other plots. Difference in leaf thickness of pears, especially palisade tissue was observed among 3 plots: the thickest occurred in A plot, intermediate in B plot and the least in C plot. Ratio of fallen leaves C plot was 1.5 times greater than that of A plot on Oct. 12. Large difference in the harvest time in grapes was found in the plants grown under different water level regimes. Earliest was on Aug. 15 in C plot, followed by B plot on Aug. 26 and Sep. 1 in A plot. Fruit color produced in C plot was found to be best. Soluble solid content of C plot fruit was lowest and acid content of fruit was highest compared to that in other plots. Root system of grapes was influenced by level of ground water table greater than produced in last year: A plot plants had many thick roots and C plot plants many rootlets. In contrast to larger number of thick root in C plot as compared to that of A plot, weight of a thick root in C plot was smaller. Similar response of root growth to water table level in pears as obtained in grape

地下水位の高低が二年生ブドウおよびナシの生育におよぼす影響を調査した.1.ブドウの新梢伸長量について, 地下水位の低いA区(-80cm水位)と中間的なB区(-50cm水位)の間には差がみられなかった.これに対し, 水位の高いC区(-20cm水位)は8月初旬に伸長が止まり, 最も小さかっった.主幹の肥大量は伸長量と同様, 水位の低いC区が最も小さく, 細かった.ナシの新梢伸長量および主幹肥大については, A・B両区間に大差はないが, 水位の高いC区が最も小さく, 主幹も細かった.2.ブドウの葉面積はA区が最も大きく, 次に水位の高いC区で, B区が最も小さかった.10月12日現在の落葉率は水位の高いC区が最も高く, 水位の低いA区の落葉率の2.6倍であった.ナシの葉面積はA区が大きく, 次いでB区, C区の順となり, 葉肉の厚さでは, 柵状組織の厚さに差異があらわれ, 水位の低いA区が最も厚く, 水位の高いC区がうすかった.さらに10月12日現在の落葉率は, 水位の低いA区を100として水位の高いC区が150で高かった.3.ブドウ果実の収穫期は各区間に差が認められ, 60%収穫率で収穫日を決定すると, C区が8月15日, B区が8月26日, A区が最も遅く, 9月1日であった.着色はC区がよかった.収穫果実の品質は, 水位の高いC区の果実が, 糖度低く, 酸含量も多かった.4.ブドウの根群の状態は地下水位の影響をうけて, 前年度よりも各区の相違が大きくなった.A区は主根の発達した大きな骨組となり, 水位の高いC・B区は細根が群生し, 濃密になっていた.C区の主根数はA区の2倍量であるが, 重さは1/5であった.5.ナシの根群の状態もブドウのそれとほぼ同様であったが, B区の根幹が特に肥大していた.C区はA区にくらべ主根, 側根の本数および重量が小さくなって, 根群の広がりが小さ

source:The technical bulletin of Faculty of Horticulture, Chiba University