Yuan J, Yan Q, Xie J, Wang J, Zhang T
Qingyuan Forest CERN, National Observation and Research Station, Shenyang, Liaoning Province, China.
CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, China.
Plant Biol (Stuttg). 2023 Jun;25(4):579-592. doi: 10.1111/plb.13519. Epub 2023 Apr 19.
Seed germination, a critical stage of the plant life cycle providing a link between seeds and seedlings, is commonly temperature-dependent. The global average surface temperature is expected to rise, but little is known about the responses of seed germination of woody plants in temperate forests to warming. In the present study, dried seeds of 23 common woody species in temperate secondary forests were incubated at three temperature sequences without cold stratification and after experiencing cold stratification. We calculated five seed germination indices and the comprehensive membership function value that summarized the above indicators. Compared to the control, +2 and +4 °C treatments without cold stratification shortened germination time by 14% and 16% and increased the germination index by 17% and 26%, respectively. For stratified seeds, +4 °C treatment increased germination percentage by 49%, and +4 and +2 °C treatments increased duration of germination and the germination index, and shortened mean germination time by 69%, 458%, 29% and 68%, 110%, 12%, respectively. The germination of Fraxinus rhynchophylla and Larix kaempferi were most sensitive to warming without and with cold stratification, respectively. Seed germination of shrubs was the least sensitive to warming among functional types. These findings indicate warming (especially extreme warming) will enhance the seedling recruitment of temperate woody species, primarily via shortening the germination time, particularly for seeds that have undergone cold stratification. In addition, shrubs might narrow their distribution range.
种子萌发是植物生命周期中的一个关键阶段，它连接着种子和幼苗，通常受温度影响。预计全球平均地表温度将会上升，但对于温带森林中木本植物种子萌发对变暖的响应却知之甚少。在本研究中，对温带次生林中23种常见木本植物的干燥种子进行了处理，分别在三种温度序列下进行培养，一种是没有经过冷层积处理，另一种是经过冷层积处理后进行培养。我们计算了五个种子萌发指数以及综合隶属函数值，该值总结了上述指标。与对照相比，未经过冷层积处理的+2℃和+4℃处理分别使萌发时间缩短了14%和16%，萌发指数分别提高了17%和26%。对于经过层积处理的种子，+4℃处理使发芽率提高了49%，+4℃和+2℃处理增加了萌发持续时间和萌发指数，并分别使平均萌发时间缩短了69%、458%、29%以及68%、110%、12%。在未经过冷层积处理和经过冷层积处理的情况下，水曲柳和日本落叶松的萌发对变暖最为敏感。在功能类型中，灌木种子萌发对变暖最不敏感。这些发现表明，变暖（尤其是极端变暖）将主要通过缩短萌发时间来增强温带木本植物的幼苗更新，特别是对于经过冷层积处理的种子。此外，灌木的分布范围可能会缩小。
