Aims

Tolerance to waterlogging and recovery ability was compared among the three subspecies of subterranean clover (Trifolium subterraneum L.) to identify tolerance mechanisms, in order to guide future subclover breeding activities.

Methods

Three cultivars each of ssp. yanninicum, subterraneum and brachycalycinum were grown in a controlled environment glasshouse with T. michelianum as a waterlogging-tolerant control. After 28 days of growth two treatments were imposed for 35 days: free-draining (control) and waterlogged. A 21-day recovery period followed.

Results

After 35 days, waterlogging reduced shoot dry weight (DW) to 58–27% and root DW to 35–21% of respective controls in each subspecies. Shoot relative growth rate (RGR) of yanninicum was least affected (78–104% of control), compared to subterraneum (51–100%) and brachycalycinum (45–69%). The subterraneum cv. Denmark had a similar response to subspecies yanninicum. Shoot RGR of T. michelianum was 138% of its control. After recovery, all traits (except tap root length) recovered to control values. Up to 21 days, the main traits associated with waterlogging tolerance (shoot and root growth) were high petiole length, less petiole anthocyanin pigmentation and high leaf chlorophyll content, but by 35 days these were a high proportion of leaf biomass, high stomatal conductance and enhanced root porosity. Average root diameter and nodulation rates were unrelated to waterlogging tolerance.

Conclusions

Subspecies yanninicum had superior waterlogging tolerance. Priority traits for easily-assessed indicators of waterlogging tolerance are less reduction of leaf size and high stomatal conductance.

中文翻译：

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三叶草的三个亚种之间的涝渍耐受性和恢复差异很大，与根系和枝条响应有关

目的

在地下三叶草的三个亚种（Trifolium subterraneum L.）之间比较了对涝渍和恢复能力的耐受性，以确定耐受性机制，以指导未来的苜蓿繁殖活动。

方法

ssp的三个品种。将yanninicum，地下和Brachycalycinum种植在带有T. michelianum作为耐涝对照的受控环境温室中。生长28天后，进行了3​​5天的两种处理：自由排水（对照）和涝渍。随后为期21天的恢复期。

结果

35天后，淹水使每个亚种的枝干干重（DW）降低至58-27％，根部DW降低至35-21％。的枝条相对生长率（RGR）yanninicum被影响最小（对照的78-104％），相比于subterraneum（51-100％）和brachycalycinum（45-69％）。该subterraneum品种。丹麦对yanninicum亚种也有类似的反应。拍摄T. michelianum的RGR是其控制权的138％。恢复后，所有性状（抽根长度除外）均恢复为对照值。在长达21天的时间里，与耐涝性相关的主要特征（茎和根的生长）是叶柄长高，叶柄花青素色素少和叶片叶绿素含量高，但到35天时，这些叶片的生物量比例高，气孔导度高和增强根部孔隙率。平均根直径和结瘤率与涝渍耐受性无关。

结论

yanninicum亚种具有优异的耐涝性。容易评估的耐涝指标的优先特征是减少叶片尺寸和提高气孔导度。