Cambial sensitivity to rising temperatures by natural condition and artificial heating from late winter to early spring in the evergreen conifer Cryptomeria japonica
Cambial sensitivity to rising temperatures by natural condition and artificial heating from late winter to early spring in the evergreen conifer Cryptomeria japonica
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DOI：
10.1007/s00468-009-0377-1
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发表时间：
2010-02-01
影响因子：
2.3
通讯作者：
Funada, Ryo
中科院分区：
文献类型：
--
作者：
Begum, Shahanara;Nakaba, Satoshi;Funada, Ryo
在自然和局部加热条件下，研究了具有不同树龄形成层的两株柳杉的形成层复活时间和木质部分化起始时间与日最高温度之和的差异。此外，我们还观察了低温对形成层活动的影响。在自然条件下，55岁和80岁的形成层重新激活和木质部分化的开始时间是不同的。在有55年历史的形成层中，形成层重新激活指数(CRI)在2007年和2008年分别为94和97摄氏度时发生，形成层重新激活指数(CRI)是根据超过10A摄氏度的日最高温度计算的。在有80年历史的形成层中，在2007年和2008年，当CRI(基于超过11A摄氏度的日最高温度计算)分别为69和71A摄氏度时，形成层重新激活。在2007年形成层重新激活后，尽管最低温度已经下降到-2到-3A℃，但形成层中的细胞分裂仍然正常，在自然条件下，木质部的分化在形成层重新激活后38-44天开始。在加热的茎中，形成层重新激活到木质部分化开始的时间为14~16天，比自然条件下的时间短得多，表明持续高温诱导了木质部的提前分化。我们的观察表明，形成层对重新激活诱导刺激的敏感性取决于形成层的休眠阶段和树龄。
Differences in the timing of cambial reactivation and the initiation of xylem differentiation in response to the sum of daily maximum temperatures were studied in two Cryptomeria japonica trees with cambium of different ages under natural and locally heated conditions. In addition, we observed the effects of low temperature on cambial activity. The timing of cambial reactivation and of the initiation of xylem differentiation differed between 55- and 80-year-old cambium under natural conditions. In the 55-year-old cambium, cambial reactivation occurred when the cambial reactivation index (CRI), calculated on the basis of daily maximum temperatures in excess of 10A degrees C, was 94 and 97A degrees C in 2007 and 2008, respectively. In 80-year-old cambium, cambial reactivation occurred when the CRI, calculated on the basis of daily maximum temperatures in excess of 11A degrees C, was 69 and 71A degrees C in 2007 and 2008, respectively. After cambial reactivation in 2007, normal cell division was evident in the cambium even though the minimum temperature had fallen between -2 and -3A degrees C. Under natural conditions, xylem differentiation started 38-44 days after cambial reactivation. In heated stems, the time between cambial reactivation and the initiation of xylem differentiation ranged from 14 to 16 days, a much shorter time than under natural conditions, indicating that continuous exposure to an elevated temperature had induced earlier xylem differentiation. Our observations indicate that the sensitivity to reactivation inducing stimuli of the cambium depends on both the stage of dormancy and tree age of the cambium.