不同生育期和氮肥水平对水稻螟虫诱集植物香根草挥发物的影响

Effect of Growth Stages and Nitrogen Fertilization on the Volatiles of Rice Stem Borer Trap Plant Vetiver Grass(Vetiveria zizanioides)

香根草挥发物在对水稻螟虫雌蛾的引诱过程中发挥重要作用。为了明确不同生育期和氮肥水平对香根草挥发物的影响,采用动态顶空吸附法和气象色谱-质谱联用仪(GC-MS)提取、分析了香根草3个不同生育期和3个不同施氮水平对其挥发物的影响。结果表明,在分离鉴定出的23种化合物中,主要为烷烃类和萜烯类化合物。其中,十四烷在香根草第Ⅲ生育期茎叶中的相对含量为31.62%,比第Ⅰ和第Ⅱ生育期时显著提高,而其他检出化合物在香根草不同生育期间的相对含量无显著差异;α-蒎烯和壬醛的相对含量在施用氮肥后显著降低,柏木脑的相对含量则在施用氮肥后显著提高,而不同的施氮水平,即10与20 g/丛对这3种化合物的相对含量无显著影响。本研究结果证明不同生育期和不同施氮水平对香根草挥发物有一定影响,香根草种植施用氮肥可以降低α-蒎烯和壬醛相对含量,提高柏木脑相对含量,为更科学地利用诱集植物香根草挥发物防治水稻螟虫奠定了基础。

Volatiles of vetiver grass Vetiveria zizanioides play an important role in trapping female moth of rice stem borer. To clarify the effect of different growth stages and nitrogen fertilization on the volatiles, volatile chemicals were collected from stem leaf of vetiver grasses during three different growth stages and from plants received three different nitrogen fertilization levels by dynamic headspace absorption method, and were analyzed by gas chromatography and mass spectrometry（GC-MS）. A total of 23 kinds of compounds were isolated and identified, most of which were alkanes and terpenes chemicals. Among them, the relative content of n-tetradecane in stems and leaves of vetiver in the III growth stage（31.62%） was significantly higher than those in the I and II growth stages, while the relative contents of other detected compounds in different growth stages were not significantly different. The relative contents of α-pinene and nonanal significantly decreased after application of nitrogen fertilizer, while those of cedrol significantly increased after application of nitrogen fertilizer. However, the differences of these three compounds between nitrogen application levels（10 and 20 g/cluster） were not significantly different. Our results indicate that different growth stages and different nitrogen levels have only a slight effect on volatiles of vetiver. These results are of significance in guiding utilization of vetiver to trap rice stem borers.