Effects of regional origin and genotype on intraspecific root communication in the desert shrub Ambrosia dumosa (Asteraceae)
Effects of regional origin and genotype on intraspecific root communication in the desert shrub Ambrosia dumosa (Asteraceae)
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DOI：
10.2307/2445959
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发表时间：
1996-01-01
影响因子：
3
通讯作者：
Callaway, RM
中科院分区：
文献类型：
--
作者：
Mahall, BE;Callaway, RM
先前的研究表明，豚草灌木根部之间发生的接触抑制具有自我/非自我识别能力。在当前的研究中，我们通过使用根观察室来观察单个根的相遇对根伸长率的影响，研究了这种识别能力的一些地理和基因型维度。我们测量了来自同一地区的植物根部之间相遇的这种效应，并将这些效应与来自两个不同地区的植物根部之间相遇的效应进行了比较。我们还测量了来自相同克隆的植物根部相遇的影响，并将这些影响与来自不同克隆的植物根部相遇的影响进行比较。来自同一地区（种群）的植物的根在接触后表现出通常的“非自身”伸长率急剧下降，但当来自不同地区的植物的根相互接触时，伸长率继续保持不变。当来自同一克隆的不同植物的根部相互接触时，与来自同一地区的不同克隆的植物的根部接触时所观察到的相同的“非自体”伸长率急剧下降。同时，在这些相同的实验中，连接到相同植物的姐妹根之间的“自我”接触没有导致伸长率的变化。因此，来自两个地理上不同的豚草种群的个体之间的差异可能足以阻碍“非自身”，种群水平上对相似性的识别显然是接触抑制所必需的。此外，“自我”识别机制排除了同一植物上两个根之间的接触抑制，其本质上似乎是生理性的，而不是遗传性的。
Previous work has shown that the contact inhibition that occurs among roots of Ambrosia dumosa shrubs has a self/nonself recognition capability. In the current study, we investigated some of the geographic and genotypic dimensions of this recognition capability by using root observation chambers to observe the effects of encounters of individual roots on root elongation rates. We measured such effects in encounters between roots of plants from the same region and compared these to effects in encounters between roots of plants from two different regions. We also measured effects of encounters between roots of plants from the same clones and compared these to effects of encounters of roots of plants from different clones. Roots of plants from the same region (population) showed the usual ''nonself'' precipitous decline in elongation rates following contact, but when roots of plants from different regions contacted each other, elongation rates continued unchanged. When roots of separate plants from the same clone contacted each other, the same ''nonself'' precipitous decline in elongation rates as seen in encounters between roots of plants of different clones from the same region occurred. Meanwhile, in these same experiments ''self'' contacts between sister roots connected to the same plants resulted in no changes in elongation rates. Thus, differences between individuals from two geographically separate populations of Ambrosia dumosa may be sufficient to thwart the ''nonself,'' population-level recognition of similarity apparently necessary for contact inhibition. Furthermore, the ''self'' recognition mechanism, which precludes contact inhibition between two roots on the same plant, appears to be physiological rather than genetic in nature.