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

木材比重是衡量木材材性的重要指标，它与针叶树茎部早、晚材形成的数量格局密切相关。本研究采用针划法和切割法观察了早、晚材形成的季节性过程，并对形成层、韧皮部和分化带中的内源激素如吲哚乙酸（IAA）、脱落酸（阿坝）和细胞分裂素（CKs）进行了测定。在整个生长季节进行了定性和定量分析。晚材数量在树间和树干中的变异与晚材细胞产生率有关，认为晚材细胞产生率受早材形成活动的影响，2）向晚材的转变是由IAA水平的显著降低引起的，IAA水平在120- 160 ng/cm ~ 2范围内降低时，晚材的转变发生 ...更多信息 ^2。IAA浓度的最大峰值影响着早材细胞向晚材转变的时间和早材细胞的产生速率。修剪后冠基部以下的茎中，IAA在相对较长的时间内保持较高水平，导致晚材细胞产量增加。阿坝作为生长抑制物质，其在树干和树木中的季节性变化很少，因此未发现其与木材形成的关系。3）在落叶和万年青树木中，即使在休眠期，形成层区的IAA含量也较低，在新芽和新叶合成IAA之前，它引起细胞分裂的重新激活。但形成层和分化初期以后的分化活性可能受到当前IAA的影响。4）在茎的形成层区发现了核糖玉米素（Ribosilzeathin），这是一种被称为促进物质的CKs。然而，与木材形成的关系没有得到承认，因为其浓度的季节变化是模糊的。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