Induced sink strength as a prerequisite for induced tannin biosynthesis in developing leaves of Populus
Induced sink strength as a prerequisite for induced tannin biosynthesis in developing leaves of Populus
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DOI：
10.1007/s00442-001-0839-7
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发表时间：
2002-02-01
期刊：
影响因子：
2.7
通讯作者：
Schultz, JC
中科院分区：
文献类型：
--
作者：
Arnold, TM;Schultz, JC
诱导防御主要发生在依赖碳水化合物输入来支持其生长和发育的年轻的、发育中的植物组织中。为了验证诱导产生的碳基防御是依赖于光合同化物的输入这一假设，我们研究了发展中的叶片的杂交白杨（美洲黑杨× P. nigra）幼树伤害舞毒蛾（舞毒蛾dispar L.）和外源茉莉酸（JA）。测定了单株叶片的生长速率、单宁含量和酸性转化酶活性，并定量了碳13标记资源在源库对之间的转移。结果表明，舞毒蛾幼虫伤害的库叶经JA处理后，其细胞壁转化酶活性显著提高。JA诱导的库叶也进口了3-4倍的C-13标记的碳从orthostichous源叶相对于控制，并分配了显着的一部分，这进口的C-13缩合单宁的生物合成。减少碳水化合物流到这些叶子，造成源叶去除，导致缩合单宁水平降低和出现的生长防御权衡。这些结果表明：（1）昆虫伤害和茉莉酸的施用诱导了杂种白杨叶片的诱导库强度;（2）输入的资源被分配给碳基防御的产生;（3）叶片从源组织输入碳水化合物的能力可以限制叶片的诱导防御水平。总之，这些结果表明，诱导阻力的冠层内的变化可能会出现部分原因是诱导叶片的资源分布不均。
Induced defenses occur predominately in young, developing plant tissues that rely upon carbohydrate import to support their growth and development. To test the hypothesis that the induced production of carbon-based defenses is dependent upon photoassimilate import, we examined the response of developing leaves of hybrid poplar (Populus deltoides x P. nigra) saplings to wounding by gypsy moth caterpillars (Lymantria dispar L.) and exogenous jasmonic acid (JA). Growth rates, condensed tannin contents and acid invertase activities were measured For individual leaves and the translocation of C-13-labeled resources between orthostichous source-sink pairs was quantified. Results showed a substantial increase in the activity of cell wall invertase in sink leaves wounded by gypsy moth caterpillars and treated with JA. JA-induced sink leaves also imported 3-4 times as much C-13-labeled carbon from orthostichous source leaves relative to controls and allocated a significant portion of this imported C-13 to condensed tannin biosynthesis. Reduced carbohydrate flow to these leaves, caused by source leaf removal, resulted in reduced condensed tannin levels and the emergence of a growth-defense tradeoff. These results indicate that (1) induced sink strength is elicited by insect wounding and JA application in hybrid poplar foliage, (2) imported resources are allocated to the production of carbon-based defenses, and (3) the level of induced defense in leaves can be constrained by the ability of leaves to import carbohydrates from source tissues. Together, these results suggest that within-canopy variations in induced resistance may arise in part because of uneven distribution of resources to induced foliage.