Growth Types and Growth Activities of Shoots, Needles and Cambium in the Genus Pinus

Abstract

マツ属の分布と種分化に関連して, 28種のマツの主軸伸長, 針葉伸長, 幹の肥大生長の各生長間の相互関係を検討した。マツ類の生長タイプを大まかに分けると, 単節型とテーダタイプに分けられる。単節型のマツ類は, 1生育期に1回の主軸伸長と針葉伸長を基本とする。一方, テーダタイプは, 1生育期に多数回の主軸伸長とそれに対応した多数回の針葉伸長を示す。両タイプは, 異なる気候条件に適応したふたつの典型的生長タイプとみなされた。年間を通じての生産物配分からみると, 単節型のマツ類は, 夏以後に主軸伸長, 針葉伸長を停止する種類が多く, それ以後に生産した物質を翌年にもちこす機構を有し, 生育期間の短かい気候に適応した生長様式をもっとみなされた。一方, テーダタイプの典型は, 極論すると物質蓄積の機構をもたず, 適時生長するという, 生育期間の長い, 暖かい気候に適応した生長様式を有すると解釈された。

In relation to distribution and speciation in the genus Pinus, seasonal growth of shoots, needles and cambium of 28 pine species was measured, which had been planted under natural condition at Kyoto. The growth course of their organs were fundamentally divided into two patterns by the shoot growth type, uninodal and Taeda type. Pines of uninodal type showed one single flush of growth in shoot and needle in the same growing season, whether early or late in seasonal variations. In pines of Taeda type, new shoots and new needles flushed repeatedly in the same season. The two growth patterns seemed to be sustained respectively by the two different cycles of carbohydrates budget through the year. In the uninodal pines, the growth cycle seemed to be sustained mainly by stored food, which pines might be more adapted to northern region. The growth cycle of Taeda type may be advantageous to warmer climate region.