Absolute Levels of Some Endogenous Hormones in stems and Wood Formation of Conifers

比重作为木材性质的重要指标，与针叶树干早材和晚材形成的数量模式密切相关。本研究用针法或切割法观察了早材和晚材形成的季节过程，并对形成层、韧皮部和分化带中的内源激素如吲哚-3-乙酸(IAA)、脱落酸(ABA)和细胞分裂素(CKS)进行了定性和定量的分析。1)树木或树干中观察到的晚材的数量变化表明了晚材细胞产生速率的关系，认为这种速率受早材形成活动的影响。即向晚材过渡的时间和早材细胞的产生率2)向晚材的过渡是由IAA水平的显著降低引起的，当IAA水平在120-160 ng/cm…范围内下降时，就会发生向晚材的过渡IAA浓度的最大峰值影响着向晚材过渡的时间和早材细胞的产量。在修剪后的树干中，IAA在相对较长的时期内维持在较高水平，导致晚材细胞产量增加。而作为生长抑制物质的ABA，无论是在茎内还是在任何树木中，其季节变化都很少，因此没有发现其与木材形成的关系。3)在落叶和常绿树木中，IAA即使在休眠期间也在茎的形成层中存在较少，并导致细胞分裂的重新激活，在新芽和新叶合成IAA之前。4)核硅玉米素存在于茎的形成层带中，是一种促进物质。然而，由于其浓度的季节变化不明显，因此与木材形成的关系并未被认识到。较少

Specific gravity used as an important index of wood properties is closely related to the quantitative pattern of early- and latewood formation in stems of conifers. In this study, seasonal process of early- and latewood formation was observed using pin-marking or cutting methods, and some endogenous hormones such as indole-3-acetic acid (IAA), abscisic acid (ABA) and cytokinins (CKs), which included in cambial, phloem and differential zone, was qualitatively and quantitatively analyzed throughout a growing season.1) The quantitative variation on latewood observed among trees or in stems of a tree indicated the relation to the rate of latewood cells production, and it was considered that the rate was influenced by activity of earlywood formation, namely the time of transition to latewood and the rate of earlywood cell production.2) The transition to latewood was brought about by the considerable reduction of IAA levels, and it occurred when the levels decreased in region of 120-160ng/cm … More ^2. Maximum peak of IAA concentration effected on the time of transition to latewood and the rate of earlywood cell production. In the stem just below crown base after pruned remarkably, IAA maintained higher level during relative long period, resulting in increase of production of latewood cells. As for ABA known as inhibiting substance for growth, the seasonal variation was little recognized within stems or in any trees, so that it was not found the relation to the wood formation.3) In deciduous and evergreen trees, IAA was present more less in cambial zone of stems even during the dormancy, and it brought about the reactivation of cell division, before IAA was synthesized in new bud and leaves. But cambial and differential activity after initial stage may be influenced by current IAA.4) Ribosilzeathin was found in cambial zone of stem, which was a kind of CKs known as promoting substance. However the relation to wood formation was not recognized, because seasonal variation on its concentration was obscure. Less