Effects of herbicides on invasive Spartina alterniflora in the Yellow River Delta

互花米草(Spartina alterniflora)作为我国危害最严重的外来入侵植物之一,严重威胁滨海湿地生态系统安全。筛选可高效灭除互花米草的除草剂,为互花米草防治提供技术支持。2017年7月在黄河三角洲潮间带对互花米草茎叶喷施不同除草剂,在施药当年和次年对互花米草生长状况和大型底栖动物密度进行跟踪调查。研究结果表明:1)高效氟吡甲禾灵对互花米草的灭除效果最好,既能杀死互花米草地上部分从而完全抑制有性繁殖,又可完全抑制次年的无性繁殖;2)氰氟草酯对互花米草的灭除效果也比较好,可以完全抑制互花米草的生长和结穗,但抑制根状茎无性繁殖能力的效果稍差,草甘膦可以完全抑制互花米草的有性繁殖,但无法抑制次年互花米草的无性繁殖;3)施用除草剂在短期内会毒害某些底栖动物,但在1年后底栖动物种群数量与对照处理无显著差异。除草剂对环境的影响程度与除草剂用量和施用时间息息相关,未来研究中,应在保证灭草效果的前提下,探索最佳用药时间和最低用量以最大限度地降低环境影响。</p

VEGETATION CHARACTERISTICS AND CONTROL TECHNIQUES OF SPARTINA ALTERNIFLORA IN DIFFERENT TIDAL FLAT HABITATS

Spartina alterniflora is one of the most harmful alien invasive species in the coastal areas of China. It is of great significance to explore efficient and feasible control technology of S. alterniflora to protect the intertidal ecological environment. Based on the long-term field investigation and in-situ experiments in the Yellow River Delta, this study revealed the efficacies of different control techniques of S. alterniflora. From the middle of June, 2018, 2 to 4 times of mowing (the stubble height was less than 3cm, and the interval between adjacent mowing events was approximately 15 days) could eliminate more than 99% of S. alterniflora, and the control efficacy was still as high as 98.8% at the end of the second growing season. Mowing plus ploughing in mid-December resulted in a controlled efficacy of 99.7% at the end of the second growing season. The tidal flat elevation gradually increased from sea to land, and the environmental factors such as soil s physical and chemical properties changed accordingly. The density, plant height and biomass of S. alterniflora increased first and then decreased with the increase of elevation. Considering the growth characteristics, habitat characteristics of S. alterniflora and the efficacies of different control techniques, a control technology system of S. alterniflora suitable for different tidal flat habitats was summarized. In the low tidal flat, middle tidal flat and high tidal flat, mowing close to the ground, mowing plus waterlogging, and mowing plus tilling were recommended, respectively. For S. alterniflora in river channels or ditches, mowing plus tilling or mowing plus waterlogging were recommended according to the factors, such as the width of the channels or ditches. For S. alterniflora on the ditch slope, mowing plus shading was recommended

一种Ru和/或Ir贵金属氧化物及其在析氧电催化的应用

物理化学带填

Photosynthetic characteristics of M9T337' apple rootstock seedlings and interaction between MdCP2 and MdGLK1 during drought stress

The cysteine protease gene MdCP2 plays an important role in responding to drought stress. In this study, the experimental materials were one-year-old M9T337' apple seedlings subjected to natural drought treatment. We determined the photosynthetic characteristics, plant water content, differentially expressed genes and the function of cysteine protease gene MdCP2 in leaves of apple seedlings during natural drought and rehydration process at physiological and molecular biological levels. The results showed that the photosynthetic rate, stomatal conductance and transpiration rate decreased under drought stress. In the later stage of natural drought, the major limiting factors of photosynthesis changed from stomatal restriction to non-stomatal restriction. The qRT-PCR results showed that MdCP2 had the higher expression level in roots and its expression had a significant positive correlation with the the degree of drought. The expression levels of MdRCA, MdCAB and MdRBCS were negative correlation with the degree of drought. Yeast two-hybrid and BiFC techniques were further used to demonstrate that MdCP2 interacts with MdGLK1. These results provide a theoretical basis for further study of cysteine protease MdCP2 gene