基于4-PHF（the four-parameter Hill function)法比较6种四照花种子的休眠特性文献综述

 2022-07-05 20:53:11

基于4-PHF（the four-parameter Hill function)法比较6种四照花种子的休眠特性

摘 要

【目的】四照花属（Cornus）树种具有很高的园林观赏价值，具有极好的开发利用前景。本研究利用4-PHF（the four-parameter Hill function)法比较6种四照花种子的休眠特性，为四照花种质资源保存、种子贮藏及开发利用等提供理论依据。【方法】以6种四照花，包括大花四照花（CF）、中国四照花（CKC）、香港四照花（CH）、东京四照花（CHT）、秀丽四照花（CHE）和尖叶四照花（CE）的种子为材料，用浓度为500 mg·L-1赤霉素（GA3）溶液浸泡3d后进行低温层积处理，并设7个层积时间梯度（0、10、20、30、40、50、60d）；采用4-PHF法拟合6种四照花种子发芽曲线，计算发芽参数包括起始发芽时间（lag）和发芽高峰时间（TMGR）及休眠指数（DI）。【结果】研究表明，层积有效地促进了四照花种子休眠的解除，但每个种达到最大发芽率所需层积时间存在差异：CKC仅需层积30d发芽率可达78%，CH和CF层积60d后发芽率分别达71%和89%，CHE、CHT和CE层积50d后发芽率分别达63%、69%和54%。用4-PHF方程拟合的发芽曲线表明：随着休眠的解除，发芽参数lag和TMGR值持续下降，DI则呈现增加的趋势。【结论】结合各个发芽指标推测认为，落叶类四照花CF、CKC种子休眠程度较浅，而常绿种CH、CHT、CHE和CE种子休眠较深；由DI值推测认为，本试验处理未能充分解除常绿类四照花的种子休眠。研究结果认为，4- PHF方程进行种子萌发曲线拟合及萌发参数lag和TMGR可从生物学角度诠释层积处理对6种四照花种子的萌发差异，但DI值不宜用于比较种间休眠程度的差异。

关键词：四照花属；起始发芽时间（lag）；发芽高峰时间（TMGR）；休眠指数(DI)

Comparisons of seed dormancy characters for 6 species in Cornus based on the four-parameter Hill function (4-PHF)

ABSTRACT

[Objectives] Tree species in Cornus are regarded as the potential plants for their excellent horticultural ornamental effects. This paper aims to compare the dormancy characteristics for 6 species in Cornus by the four-parameter Hill function (4-PHF) and to provide a theoretical basis for germplasm resources conservation, seed storage, development and utilization of Cornus. [Method] Seeds of 6 species in Cornus, including C. florida (CF), C. kousa subsp. chinensis (CKC), C. hongkongensis (CH), C. hongdongensis subsp. tonkinensis (CHT), C. hongdongensis subsp. elegans (CHE) and C. elliptica (CE), were subjected to stratification after soaking 3d with 500 mg·L-1 GA3; 7 gradients of stratification duration were designed as: 0, 10, 20, 30, 40, 50 and 60d. Furthermore, 4-PHF（four-parameter Hill function）was used as a curve-fitting method to describe germinating patterns and estimate germination parameters, including the time at germination onset (lag), time at maximum germination rate (TMGR) and dormancy index (DI), for 6 dogwood species. [Result] Our results revealed that stratification promoted effectively the releasing of dogwoods seed dormancy. However, the maximums of germination for 6 species occurred at various stratification periods: 78% of germination for CKC reached at 30d stratification; 71% and 89% for CH and CF at 60d, while 63%, 69% and 54% for CHE, CHT and CE at 50d, respectively. The germination curves fitted by 4-PHF showed that germination parameters of lag and TMGR decreased steadily, as well as DI increased with the releasing of seed dormancy. [Conclusion] Combing all germination index, we speculate the deeper dormancy in evergreen dogwoods than in deciduous ones. Our results also found that the germination curve-fitting and the estimated parameters (lag and TMGR) using 4-PHF could interpret biologically the seed germination differences among 6 species under stratification, however, DI do not lend itself to compare the differences of dormancy degree among various species.

Key words：Cornus; time at germination onset (lag); time at maximum germination rate; dormancy index (DI)

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