THE RESPONSE OF FIELD-GROWN LUCERNE TO A MANIPULATED RANGE OF INSECT-INDUCED NITROGEN STRESSES
THE RESPONSE OF FIELD-GROWN LUCERNE TO A MANIPULATED RANGE OF INSECT-INDUCED NITROGEN STRESSES
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DOI：
10.1111/j.1744-7348.1988.tb03295.x
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发表时间：
1988-08-01
影响因子：
2.6
通讯作者：
BOURDOT, GW
中科院分区：
文献类型：
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作者：
GOLDSON, SL;JAMIESON, PD;BOURDOT, GW
G. W. BOURDOT* 总结使用一个简单的模型分析了一年生卢塞恩（Medicago sativa）林分在氮胁迫下的生长情况，该模型将生长与截获的光合有效辐射（PAR）联系起来。通过在林分中建立一系列的圆板甲（Sitona discoideus，鞘翅目：菜粉蝶科）幼虫种群来系统地诱导氮胁迫，幼虫密度与牧草氮浓度（N%）之间的强线性关系证实了圆板甲幼虫的取食对植物固氮根瘤的直接影响。氮胁迫对牧草生产的负面影响在氮含量为4- 7%时突然变得明显。氮胁迫下植株干物质生产损失的87%与冠层利用PAR的能力下降有关，而不是与PAR截获量减少有关。discoideus幼虫与干旱的关系比最初认为的要小。据推测，当重新建立的根瘤菌根瘤种群需要比固定更多的氮时，损害突然发生。
G. W. BOURDOT*SUMMARYThe growth of a 1‐yr‐old lucerne (Medicago sativa) stand subjected to nitrogen stress was analysed using a simple model that related growth to intercepted photosynthetically active radiation (PAR). Nitrogen stress was systematically induced by establishing a range of populations ofSitona discoideus(Coleoptera: Curculionidae) larvae in the stand. The direct influence of their feeding on the plants' nitrogen‐fixing root rhizobial nodules was confirmed by the strong linear relationship found between larval density and herbage nitrogen concentration (N%). The negative effect of nitrogen stress on herbage production was found to become abruptly apparent at an N% level of 4–7%. Eighty‐seven percent of the loss in dry matter production in the nitrogen‐stressed plants was associated with a decline in the ability of the canopy to use PAR, rather than a reduction in the amount of PAR intercepted.From the results obtained it was concluded that the damage effects ofS. discoideuslarvae were less drought‐related than initially thought. It is speculated that the abrupt onset of damage occurred when the re‐establishing rhizobial root nodule population demanded more nitrogen than it fixed.