Departement des Sciences Fondamentales, Université du Québec à Chicoutimi, 555, boulevard de l'Université, Chicoutimi, Quebec, Canada.
Plant Cell Environ. 2010 Oct;33(10):1721-30. doi: 10.1111/j.1365-3040.2010.02176.x.
Delays in the start of the growing season reduce the period available for growth and the amount of xylem production. However, a higher number of developing tracheids could prolong cell differentiation and, consequently, lengthen the growing season. The relationship between the amount and duration of cell production in the xylem remains an unresolved issue. The aim of this study was to resolve the chicken-or-egg causality dilemma about duration of growth and cell production through simple- and double-cause models. This was achieved by (1) analysing the intra-annual growth dynamics of the xylem in Picea mariana (Mill.) BSP during 2006-2009 in two contrasting sites of the boreal forest of Quebec, Canada, and (2) extracting the dates of onset and ending of xylem formation and the number of radial cells along the tree ring. A higher number of cells was linked to an earlier onset (r=0.74) and later ending (r=0.61) of cell differentiation. The absence of a relationship between the residuals of the onset and ending of xylogenesis (r(p)=-0.06) indicated that cell production influenced the correlation between the two phenophases of the xylem. These results demonstrated that a higher number of cells produced delay the ending of xylem maturation, so extending the duration of wood formation.
生长季节开始的延迟会减少生长时间和木质部产量。然而，更多的发育中的导管可以延长细胞分化，从而延长生长季节。木质部中细胞产生的数量和持续时间之间的关系仍然是一个未解决的问题。本研究的目的是通过简单和双重原因模型来解决生长时间和细胞产生的因果关系难题。这是通过（1）分析 2006-2009 年在加拿大魁北克的两个北方森林对比地点的黑云杉（Picea mariana（Mill.）BSP）木质部的年内生长动态，以及（2）提取木质部形成的开始和结束日期以及树木年轮上的径向细胞数量来实现的。更多的细胞与细胞分化的更早开始（r=0.74）和更晚结束（r=0.61）有关。木质部发生开始和结束的残差之间没有关系（r(p)=-0.06），这表明细胞产生影响了这两个木质部物候阶段之间的相关性。这些结果表明，更多的细胞产生会延迟木质部成熟的结束，从而延长木材形成的时间。
