多效唑对少花蒺藜草生物学特性的影响

为防治和遏制入侵植物少花蒺藜草(Cenchrus pauciflorus)生长及扩散，对分蘖期的少花蒺藜草喷施不同浓度的多效唑，成熟期测定其株高、分蘖数、穗长、穗数、穗粒数和各器官生物量，计算茎叶比、根冠比和各器官贡献率。结果表明：多效唑浓度为100 mg·L^-1时，对少花蒺藜草株高抑制效果最明显；随着多效唑浓度的增大，少花蒺藜草的叶片生物量显著增加、根系生物量显著下降，茎叶比和根冠比显著下降(P<0.05)；当多效唑施用浓度达到300 mg·L^-1时，少花蒺藜草的穗数最少，根系生物量、根冠比和茎叶比最小；当施用400 mg·L^-1的多效唑时，叶片生物量最大，穗粒数最少。综合来看，低浓度的多效唑可有效降低少花蒺藜草株高，而较高浓度的多效唑，可抑制少花蒺藜草分蘖，减少有效穗数及穗粒数。

Effects of Paclobutrazol on Biological Characteristics of Cenchrus pauciflorus

To prevent and control the growth and diffusion of invasive plant Cenchrus pauciflorus,different concentrations of paclobutrazol were sprayed on Cenchrus pauciflorus at tillering stage.The plant height,tiller number,ear length,ear number,grain number per ear,and biomass of each type of organ were measured at maturity,and the stem leaf ratio,root shoot ratio,and contribution rate of each organ were calculated.The results showed that when the concentration of paclobutrazol was 100 mg·L^-1,the control effect on the plant height of Cenchrus pauciflorus was the most obvious.With the increase of paclobutrazol concentration,the leaf biomass increased significantly,the root biomass decreased significantly,and the stem leaf ratio and root shoot ratio decreased significantly(P<0.05).When the application concentration of Paclobutrazol was 300 mg·L^-1,the number of panicles,root biomass,root shoot ratio,and stem leaf ratio were the least.When 400 mg·L^-1 paclobutrazol was administered,the leaf biomass was the largest and the number of grains per ear was the least.Overall,a low concentration of paclobutrazol can effectively reduce the plant height of Cenchrus pauciflorus,while a high concentration of paclobutrazol can inhibit the tillering of Cenchrus pauciflorus,and reduce the number of effective panicles and grains per panicle.