研究了室内条件下信息化合物及稻飞虱卵的形态特征在稻虱缨小蜂识别2种卵寄主褐飞虱和白背飞虱中的作用。结果表明，褐飞虱和白背飞虱雌成虫诱导的水稻挥发物对稻虱缨小蜂的引诱作用显著差异，各自的引诱比例（头数）分别为57.50%（23头）和42.50%（17头）。稻虱缨小蜂对2种飞虱4组材料，完整卵、磨碎卵、带卵叶鞘和若虫为害叶鞘的行为反应，除了在褐飞虱完整卵上的搜索时间极显著地长于在白背飞虱完整卵上的以外，其余的均不存在差异。挥发物捕集结果表明，褐飞虱和白背飞虱雌成虫诱导的水稻挥发物组成相非常一致。上述结果表明水稻挥发物、稻飞虱利它素及飞虱卵的形态特征在稻虱缨小蜂识别褐飞虱和白背飞虱卵中的作用不明显。文中就稻虱缨小蜂识别2种寄主的机制进行了讨论。

利用行为生测考察了褐飞虱为害程度、水稻生育期和品种对水稻挥发物引诱褐飞虱卵期寄生蜂稻虱缨小蜂活性的影响。结果表明，雌成虫10头/株和20头/株为害1d的水稻挥发物，对稻虱缨小蜂具明显的引诱作用，而1头/株、5头/株、40头/株和80头/株为害1d的，与空白对照相比不显示明显的引诱作用。稻虱缨小蜂对TN1未处理稻株挥发物的趋性不明显，并且对不同生育期的稻株亦无明显差异；但受褐飞虱为害后，生育期60d的稻株比90d的对稻虱缨小蜂具更强的引诱作用。不同品种未处理稻株间，TN1挥发物对稻虱缨小蜂的引诱作用明显地比Nabeshi强，而其他品种间差异不显著。在受到褐飞虱为害后，品种间的差异趋于明显。汕优63比TN1具更强的引诱作用，而Nabeshi、IR26和丙97-59等品种对稻虱缨小蜂的引诱作用则明显弱于TN1。

Experiments were conducted in laboratory to study the impacts of rice genotypes and rice plants treated with different levels of nitrogen on the predation rates of the predator, Cyrtorhinus lividipennis Reuter, for eggs of the rice brown planthopper (BPH), Nilaparvata lugens (St

Allopolyploid speciation occurs instantly when the genomes of different species combine to produce self-fertile offspring and has played a central role in the evolution of higher plants, but its consequences for adaptive responses are unknown. We compare herbivore-recognition and-resistance responses of the diploid species and putative ancestral parent Nicotiana attenuata with those of the two derived allopolyploid species Nicotiana clevelandii and Nicotiana bigelovii. Manduca sexta larvae attack all three species, and in N. attenuata attack is recognized when larval oral secretions are introduced to wounds during feeding, resulting in a jasmonate burst, a systemic amplification of trypsin inhibitor accumulation, and a release of volatile organic compounds, which function as a coordinated defense response that slows caterpillar growth and increases the probability of their being attacked. Most aspects of this recognition response are retained with modifications in one allotetraploid (N. bigelovii) but lost in the other (N. clevelandii). Differences between diploid and tetraploid species were apparent in delays (maximum 1 and 0.5h, respectively) in the jasmonate burst, the elicitation of trypsin inhibitors and release of volatile organic compounds, and the constitutive levels of nicotine, trypsin inhibitors, diterpene glycosides, rutin, and caffeoylputrescine in the leaves. Resistance to M. sexta larvae attack was most strongly associated with diterpene glycosides, which were higher in the diploid than in the two allotetraploid species. Because M. sexta elicitors differentially regulate a large proportion of the N. attenuata transcriptome, we propose that these species are suited for the study of the evolution of adaptive responses requiring trans-activation mechanisms.

Although nitrogen (N) availability is known to alter constitutive resistance against herbivores, its influence on herbivoreinduced responses, including signaling pathways, transcriptional signatures, and the subsequently elicited chemical defenses is poorly understood. We used the native tobacco, Nicotiana attenuata, which germinates in the postfire environment and copes with large changes in soil N during postfire succession, to compare a suite of Manduca sexta- and elicitor-induced responses in plants grown under high- and low-N (LN) supply rates. LN supply decreased relative growth rates and biomass by 35% at 40d compared to high-N plants; furthermore, it also attenuated (by 39 and 60%) the elicitor-induced jasmonate and salicylate bursts, two N-intensive direct defenses (nicotine and trypsin proteinase inhibitors, albeit by different mechanisms), and carbon-containing nonvolatile defenses (rutin, chlorogenic acid, and diterpene glycosides), but did not affect the induced release of volatiles (cis-a-bergamotene and germacrene A), which function as indirect defenses. M. sexta and methyl jasmonateinduced transcriptional responses measured with a microarray enriched in herbivore-induced genes were also substantially reduced in plants grown under LN supply rates. In M. sexta-attacked LN plants, only 36 (45%) up-regulated and 46 (58%) down-regulated genes showed the same regulation as those in attacked high-N plants. However, transcriptional responses frequently directly countered the observed metabolic changes. Changes in a leaf's sensitivity to elicitation, an attacked leaf's waning ability to export oxylipin wound signals, and/or resource limitations in LN plants can account for the observed results, underscoring the conclusion that defense activation is a resource-intensive response.