COORDINATION OF PHOTOSYNTHETIC AND ALKALOIDAL RESPONSES TO DAMAGE IN UNINDUCIBLE AND INDUCIBLE NICOTIANA-SYLVESTRIS
COORDINATION OF PHOTOSYNTHETIC AND ALKALOIDAL RESPONSES TO DAMAGE IN UNINDUCIBLE AND INDUCIBLE NICOTIANA-SYLVESTRIS
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DOI：
10.2307/1939424
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发表时间：
1994-06-01
期刊：
影响因子：
4.8
通讯作者：
OHNMEISS, TE
中科院分区：
文献类型：
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作者：
BALDWIN, IT;OHNMEISS, TE
对于大多数植物来说，食草动物攻击后的防御和再生并不是相互排斥的选择，但很少有研究研究探讨负责这两种植物功能的过程的协调。为此，我们研究了协调的杀藻和光合作用的反应，以模拟草食动物在两个实验中的硝酸盐供应率的范围内生长的植物叶片氮的变化的背景下。在第一个实验中，损害引起的变化，叶片烟碱，总氮，硝酸盐和光合速率（PR）进行了监测，在相同年龄的未受损叶片的年轻的欧洲烟草植物生长在盆。在第二种情况下，通过在盆栽中种植植物>150 d，使对损害的烟碱反应与损害分离，从而使它们对增加的烟碱浓度的叶片损害没有反应（“不可诱导的”）。我们认为，由损伤引起的PR和尼古丁含量的变化分别反映了资源对再生和防御的分配，并检查最佳防御（OD）理论对这些反应的预测。我们以前已经确定，无论是组成或诱导尼古丁的生产是一个被动的结果，氮失衡超过生长的要求，是预测的碳/营养（C/N）理论。如果PR反映的健身值的叶子和损害反映了未来的损害的概率很高，我们解释的OD理论预测PR和尼古丁含量应该是相关的，和损害应该增加分配给一个给定的PR的尼古丁的量。尼古丁，氮，PR增加了协调的方式在诱导植物叶损伤。在这两个实验中，PR和氮是高度相关的，但损害并不影响PR-氮的关系。在第一个实验诱导植物，尼古丁和氮也高度相关。然而，损害显着增加尼古丁-氮关系的斜率1.6倍。同样，尼古丁和PR显著相关，尼古丁-PR关系的斜率在对损伤的反应中显著增加（1.9倍）。这些结果与OD理论的预测相一致，尽管这种协调，光合作用和光合作用的反应可以解耦。无论硝酸盐供应率，受损的“不可诱导的”植物表现出尼古丁含量没有显着增加，但显着增加了他们的PR在响应损害与相关的叶片氮含量增加。烟碱和PR在未受损植株中不显著相关，但在受损植株中显著相关。除非在不可诱导的植物中激活其他防御，否则这些结果可能反映了生长速率缓慢或生根量减少的不可诱导的植物中生长优先于防御。
Defense and regrowth after herbivore attack are not mutually exclusive alternatives for most plants, yet few studies have examined the coordination of the processes responsible for these two plant functions. To this end, we studied the coordination of alkaloidal and photosynthetic responses to simulated herbivory in the context of changes in leaf nitrogen in plants grown under a range of nitrate supply rates in two experiments. In the first experiment, damage-induced changes in leaf nicotine, total nitrogen, nitrate, and photosynthetic rate (PR) were monitored in same-aged undamaged leaves of young Nicotiana sylvestris plants grown in pots. In the second, the alkaloidal response to damage was uncoupled from damage by growing plants in pots for >150 d, causing them not to respond to leaf damage with increased nicotine concentrations (''uninducible'').We propose that the changes in PR and nicotine content induced by damage reflect the allocation of resources to regrowth and defense, respectively, and examine the predictions of the optimal defense (OD) theory regarding these responses. We have previously established that neither constitutive nor induced nicotine production is a passive consequence of a nitrogen imbalance in excess of growth requirements as is predicted by the carbon/nutrient (C/N) theory. If PR reflects the fitness value of the leaf and damage reflects a high probability of future damage, we interpret the OD theory to predict that PR and nicotine content should be correlated, and that damage should increase the amount of nicotine allocated for a given PR.Nicotine, nitrogen, and PR increased in a coordinated fashion in response to leaf damage in the inducible plants. In both experiments, PR and nitrogen were highly correlated, but damage did not affect the PR-nitrogen relationship. In the first experiment with inducible plants, nicotine and nitrogen were also highly correlated. However, damage significantly increased the slope of the nicotine-nitrogen relationship 1.6-fold. Similarly, nicotine and PR were significantly correlated and the slope of the nicotine-PR relationship increased significantly (1.9-fold) in response to damage. These results are consistent with the predictions of the OD theory.Despite this coordination, alkaloidal and photosynthetic responses can be uncoupled. Regardless of nitrate supply rate, damaged ''uninducible'' plants exhibited no significant increase in nicotine content, but significantly increased their PR in response to damage with a correlated increase in leaf nitrogen content. Nicotine and PR were not significantly correlated in undamaged plants, but were significantly correlated in damaged plants. Unless other defenses are activated in uninducible plants, these results may reflect a priority of growth over defense in uninducible plants with slow growth rates or reduced rooting volume.