Root Distribution and Potential Interactions Between Allelopathic Rice, Sprangletop (Leptochloa spp.), and Barnyardgrass (Echinochloa crus-galli) based on 13C Isotope Discrimination Analysis
Root Distribution and Potential Interactions Between Allelopathic Rice, Sprangletop (Leptochloa spp.), and Barnyardgrass (Echinochloa crus-galli) based on 13C Isotope Discrimination Analysis
复制标题
DOI：
10.1007/s10886-013-0246-7
复制
发表时间：
2013-02-01
影响因子：
2.3
通讯作者：
Duke, Sara
中科院分区：
文献类型：
--
作者：
Gealy, David;Moldenhauer, Karen;Duke, Sara
杂草抑制水稻品种有望改善和更经济地进行水稻杂草管理。人们认为水稻根部和杂草之间的相互作用受到一些水稻品种的杂草抑制活性的调节，但这些现象很难测量，也没有得到很好的理解。因此，在美国阿肯色州斯图加特的一项为期两年的研究中，对 11 个水稻品种和两种杂草的地上生产力、杂草抑制和根系分布进行了评估。在稗草（稗草（Echinochloa crus-galli (L.) Beauv.）或髯金雀花）侵染的田间地块中对化感作用品种 PI 312777 和 Taichung Native 1 (TN-1)、其他三个杂草抑制品种、三个籼稻衍生育种选择和三个非抑制性商业品种进行了评估（千金子，Leptochloa fusca (L.) Kunth var. fascicularis (Lam.) N. Snow）。与育种选择或非抑制性品种相比，化感作用品种产生更多的分蘖，并在更大程度上抑制两种杂草。对 15 厘米深度的混合根样品进行 C-13 同位素辨别分析表明，与育种选择或非抑制性品种相比，化感作用品种通常在 0-5 厘米土壤深度的表面产生更大比例的总根质量，后者倾向于将其根更均匀地分布在整个土壤剖面中。在无杂草和杂草侵染的地块中，根群分布的这些趋势在早期（洪水前）和晚季阶段都很明显。品种生产力和根系分布对与两种杂草的竞争的反应通常相似，但稗草对水稻产量和根系质量的降低程度比金缕梅更大。这些发现首次证明，在美国漫灌水稻生产系统的杂草侵染和无杂草条件下，化感作用品种 PI 312777 和 TN-1 的根部比非抑制性品种更彻底地探索上层土壤剖面。他们提出了一个有趣的前景，即土壤表面附近的根系增殖可能会增强根部释放的化感化学渗出物的杂草抑制活性。用于杂草抑制活性的植物结构设计应考虑这些性状以及其他经过验证的农艺性状，例如高分蘖和产量。
Weed-suppressive rice cultivars hold promise for improved and more economical weed management in rice. Interactions between roots of rice and weeds are thought to be modulated by the weed-suppressive activity of some rice cultivars, but these phenomena are difficult to measure and not well understood. Thus, above-ground productivity, weed suppression, and root distribution of 11 rice cultivars and two weed species were evaluated in a drill-seeded, flood-irrigated system at Stuttgart, Arkansas, USA in a two-year study. The allelopathic cultivars, PI 312777 and Taichung Native 1 (TN-1), three other weed-suppressive cultivars, three indica-derived breeding selections, and three non-suppressive commercial cultivars were evaluated in field plots infested with barnyardgrass (Echinochloa crus-galli (L.) Beauv.) or bearded sprangletop (sprangletop, Leptochloa fusca (L.) Kunth var. fascicularis (Lam.) N. Snow). The allelopathic cultivars produced more tillers and suppressed both weed species to a greater extent than did the breeding selections or the non-suppressive cultivars. C-13 isotope discrimination analysis of mixed root samples to a depth of 15 cm revealed that the allelopathic cultivars typically produced a greater fraction of their total root mass in the surface 0-5 cm of soil depth compared to the breeding selections or the non-suppressive cultivars, which tended to distribute their roots more evenly throughout the soil profile. These trends in root mass distribution were apparent at both early (pre-flood) and late-season stages in weed-free and weed-infested plots. Cultivar productivity and root distribution generally responded similarly to competition with the two weed species, but barnyardgrass reduced rice yield and root mass more than did sprangletop. These findings demonstrate for the first time that roots of the allelopathic cultivars PI 312777 and TN-1 explore the upper soil profile more thoroughly than do non-suppressive cultivars under weed-infested and weed-free conditions in flood-irrigated U.S. rice production systems. They raise the interesting prospect that root proliferation near the soil surface might enhance the weed-suppressive activity of allelochemical exudates released from roots. Plant architectural design for weed suppressive activity should take these traits into consideration along with other proven agronomic traits such as high tillering and yield.