攀枝花市麻疯树老树特征的初步研究

本文初步研究了攀枝花市不同年龄与生境的麻疯树老树,分析了老树特征与衰老的环境诱导结构限制现象。结果表明：（1）麻疯树衰老树体相对地径（16 cm～62 cm）、树龄（15 a～41 a）、冠幅（3 m×3 m～8.5 m×8.5m）、高度（2 m～6.96 m）较大,一级枝较大,有一定比例的枯死枝;（2）新梢小（枝径0.7 cm～1.12 cm;长度7 cm～28 cm之间）,生长量低,萌生枝稀少,生殖枝比例偏低（趋近于30%以下）;（3）单枝坐果量低（0～3个）,干果重量1.65 g,千粒重490 g,壳比例30%,适合度偏低;（4）生境肥沃时树龄偏大,衰老程度弱,而生境瘠薄时树龄小,衰老程度强烈;（5）不考虑环境异质性,则衰老为树体结构限制的结果,新梢大小小于分支阈值,丧失了树体发育的能力而成为限制生长的因素。综合分析,麻疯树老树指标是分支率,在分支率为1时衰老启动;形态上衰老为环境诱导结构限制的产物,而结构限制可能是衰老的主观因素。

The Preliminary Researches on the Characteristics of Old Trees of Jatropha curcasin Panzhihua City

This paper dealt preliminarily with the old Jatropha curcas trees of different ages and habitats in Panzhihua City,analyzed the tree features and senescence phenomenon of architecture limitation that the environment induced.Results indicated as follows：（1） there were relative larger diameter（16 cm~62 cm）,tree age（15 a~41 a）,tree crown（3 m×3 m~8.5 m×8.5 m）,tree height（2 m~6.96 m）,stronger first-class branches and some dying branches in a proportion of 0~30%;（2） the new branch had a little diameter（0.7 cm~1.12 cm） and length（7 cm~28 cm）,lower growth rate,more sparse branches that germinated after disturbance,and reproduction branches with a lower proportion（below 30%）;（3） the old tree had a lower fruit yield of single branch（0~3）,1.65 g of the dry fruit weight,0.49 g of the weight of 1 000-seeds,and 30% of the shell proportion,and totally had a lower fitness of reproduction;（4） the tree size was larger with a lower aging degree in the fertilized habitat,and the smaller with a stronger aging in the poor habitat;（5） in no consideration of environment heterogeneity,it was concluded that the aging was the results of tree architecture limitation.The size of new branch this year was lower than the branching threshold,lost the tree developing capacity and became a factor of imitating the growth.Comprehensively,the aging index of J.curcas was the branching ratio and started the tree aging with one of bifurcation ratio,which implied that the morphological aging was the results of tree architecture limitation of the environment induction,but the architecture limitation was possibly the subjective factor of aging.