外源赤霉素GA3对偃麦草属植物种子萌发特性的影响

Effects of exogenous gibberellin on seed germination characteristics of Elytrigia species

摘要:

促进偃麦草属植物种子萌发是偃麦草属植物栽培草地成功建植的关键。通过不同浓度外源赤霉素 GA₃溶液(0、500、1 000、1 500 和 2 000 mg/L)对长穗偃麦草、中间偃麦草和偃麦草种子进行浸种处理，分析外源 GA₃对 3 种偃麦草属植物种子萌发及生理特性的影响。结果表明：随外源 GA₃处理浓度的增加，3 种偃麦草属植物种子发芽率和发芽势均显著提高，1 500 mg/L 是最适合打破种子休眠而萌发的浓度；GA₃浸种处理促进了 3 种偃麦草属植物种子胚根和胚芽的生长，提高了内源生长促进物质 IAA 和 GA₃ 含量，降低生长抑制物质 ABA 含量，且提高了胚芽的 POD 活性，降低了 MDA 含量。 1 500 mg/L 外源 GA₃浸种处理可较好地调控种子内源激素含量继而促进种子萌发，为偃麦草属植物种子高效生产和草地建植提供了理论依据。

Abstract:

Promoting the seed germination of Elytrigia species is the key to the successful establishment of culti- vated grassland. In this study，the seed germination and physiological characteristics of E. elongata，E. intermedia and E. repens were studied by soaking the seeds in the different concentrations of exogenous gibberellin GA₃ solution (0， 500，1 000，1 500，and 2 000 mg/L). The results showed that with the increase of GA₃ concentration，the seed germi- nation rate and germination potential of the three Elytrigia species were significantly increased. The 1 500 mg/L GA₃ concentration was the most suitable concentration for breaking seed dormancy and improving germination. After soak- ing the seeds with GA₃ solution，both radicle length and sprout length were promoted. The IAA and GA₃ contents of seeds were increased，while the ABA content was decreased. Furthermore，the POD activity of the sprouts of three Elytrigia species was increased，while the content of MDA was decreased. In conclusion，seed soaking with 1 500 mg/L exogenous gibberellin GA₃ could regulate the endogenous hormone content and promote seed germination. The results provide an important theoretical basis for the efficient seed production and grassland establishment of Ely- trigia species.