Growth characteristics of root-shoot relations of three birch seedlings raised under different water regimes
Growth characteristics of root-shoot relations of three birch seedlings raised under different water regimes
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DOI：
10.1023/a:1026199402085
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发表时间：
2003-08
期刊：
影响因子：
4.9
通讯作者：
T. Koike;M. Kitao;A. Quoreshi;Y. Matsuura
中科院分区：
文献类型：
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作者：
T. Koike;M. Kitao;A. Quoreshi;Y. Matsuura
3种白桦（Betula ermanii，B. maximowicziana，B.广泛分布于日本北方的Platyphyllavar.japonica）在不同的水分状况下（约. 23%、35%和60%），研究其根冠生长量和气体交换特性与生境选择的关系。所有桦树的总生物量较大的中等，湿和干处理。最大根长B.在干湿条件下，阔叶树的生长量均高于其它树种。3种白桦的根系生长速率在7月中旬至9月上旬达到最大值，而新梢生长速率在6月下旬至8月中旬达到最大值。干旱和湿润处理均抑制了白桦根系的生长，尤其是白桦。ermanii。干、湿条件下3种白桦生物量分配到根系的比例在30%~ 40%之间，但主要分配到伸长根长上。B.细根埃尔曼尼亚湾在湿润条件下，Maximowicziana主要分布在土壤表层。在干处理中，B.白桦分配光合产物使根长和细根产量（< 2 mm）增加，根系对不同水分条件的可塑性最强。3种白桦的比叶面积均随土壤含水量的降低而降低。B.以阔叶树最大。叶片净光合速率（Pn）和水分利用效率（WUE）均高于对照。在所有处理中，以阔叶树表现最好。叶片氮含量。白桦在不同水分条件下的生长量也相对高于其他两种白桦，白桦B.在不同的水分条件下，阔叶树可以适应不同的生长环境。
Three birch species (Betula ermanii, B. maximowicziana, B. platyphyllavar.japonica) widespread in northern Japan were raised under different water regimes (ca. 23, 35, and 60%) to study root-shoot increment and gas exchange traits in relation to their habitat preferences in natural conditions. Total biomass of all birches was larger for medium, wet and dry treatment. Maximum root length ofB. platyphyllaraised at dry or wet condition was higher than other species. Root growth rate of three birches peaked around mid July to early September while shoot growth rate was found maximum between late June and mid August. Root growth of three birches was suppressed under dry and wet treatment, especially forB. ermanii. Allocation percentage of biomass to roots of three birches ranged from 30 to 40% but it mainly allocated to elongate the root length under dry and wet condition. Fine roots ofB. ermaniiandB. maximowiczianaunder wet condition were distributed mainly on soil surface. In the dry treatment,B. platyphyllaallocated photosynthates to elongate the root length and fine root production (< 2 mm) and had highest plasticity of roots to different water conditions among the three birches. Specific leaf area (SLA) of three birches decreased with decreasing soil moisture content. Plasticity in SLA ofB. platyphyllawas found largest. Net photosynthetic rate (Pn) and water use efficiency (WUE) ofB. platyphyllashowed highest among all the treatments. Leaf nitrogen content ofB. platyphyllawas also relatively higher under different water conditions as compared to the other two birch species, suggestingB. platyphyllamay enable to invade to various growing conditions with different water regimes.