桢楠种子萌发过程中内源激素对温度变化的响应

【目的】研究低温(4℃)保存和自然保存两种处理后,桢楠种子在恒温(25℃)和变温(15℃/25℃)条件的萌发过程中,种子内源激素含量及其动态变化,以及内源激素与种子萌发率的关系,为阐明桢楠种子的萌发机制提供理论基础,也为其繁育与开发应用提供参考依据。【方法】采用酶联免疫吸附测定法对桢楠种子的内源激素含量及动态变化进行测定。【结果】1)自然保存的种子在恒温(25℃)条件下发芽率不足30%,最高为27.3%,在变温(15℃/25℃)条件下的发芽率不足40%,最高为37.0%,而经过低温(4℃)处理的种子在变温(15℃/25℃)条件下的发芽率最高可达66.0%;2)经过低温(4℃)处理后的种子在变温(15℃/25℃)条件下的内源激素含量GA3为417.17 ng·g-1,IAA为211.67 ng·g-1,ZR为47.69 ng·g-1,均高于恒温(25℃)下的GA3、IAA、ZR含量,GA3和ZR含量呈现出先上升后下降趋势,ABA和IAA含量则表现为先下降后上升趋势;3)在变温(15℃/25℃)条件下内源激素GA3/ABA、ZR/ABA、(GA3+IAA+ZR)/ABA比值均比恒温(25℃)条件下高;4)在恒温(25℃)条件和变温(15℃/25℃)条件下的种子发芽率与GA3/ABA、IAA/ABA、ZR/ABA及(GA3+IAA+ZR)/ABA的比值均呈显著或极显著正相关。【结论】低温(4℃)可以解除桢楠种子的休眠,显著提高种子的发芽率,在变温(15℃/25℃)条件能够打破种子内源激素间的平衡,增加促进种子萌发的内源激素含量,降低抑制种子萌发的内源激素含量,进而提高种子的发芽率。

Response of endogenous hormone to temperatures changes during the seed germination of Phoebe zhennan

【Objective】The relationship between endogenous hormone content and dynamic changes and endogenous hormones and Phoebe zhennan seeds germination during the germination of Phoebe zhennan seeds at constant temperature(25°C)and temperature change(15°C/25°C)after low temperature(4°C)and natural preservation was investigated,and to provide a theoretical basis for clarifying the germination mechanism of Phoebe zhennan seeds,and also to provide a reference for its breeding and development.【Method】The endogenous hormone content and dynamic changes of Phoebe zhennan seeds were determined by enzyme-linked immunosorbent assay(ELISA).【Result】1)The germination rate of naturally preserved seeds was less than 30%under constant temperature conditions,the highest was 27.3%,and the germination rate under variable temperature conditions was less than 40%,the highest was 37.0%,while the germination rate is up to 66.0%when the seeds treated with low temperature in variable temperature conditions.2)The contents of endogenous hormones GA3,IAA and ZR in the seeds after low temperature treatment are:417.17 ng·g-1,211.67 ng·g-1,47.69 ng·g-1 respectively.all higher than the GA3,IAA and ZR content under constant temperature,and the GA3 and ZR contents performance a trend first rise and then decline,while the ABA and IAA content trends were opposite with this,showing a trend first decline and then rise.3)The ratios of endogenous hormones GA3/ABA,ZR/ABA and(GA3+IAA+ZR)/ABA under the condition of temperature change are higher than those under constant temperature.4)There was a significant or extremely significant positive correlation between the seed germination ratio and the ratio of GA3/ABA,IAA/ABA,ZR/ABA and(GA3+IAA+ZR)/ABA under constant temperature and change temperature conditions.【Conclusion】Low temperature can relieve the dormancy of Phoebe zhennan seeds and increase the germination rate significantly,and can break the balance between endogenous hormones under the condition of temperature change,increase the endogenous hormone content of seed germination and reduce endogenous hormone content that inhibits seed germination,thereby improve the germination rate of Phoebe zhennan seeds.