不同夏季休眠程度的鸭茅基因型中生长、脱水素和水溶性碳水化合物的季节性模式
Seasonal patterns of growth, dehydrins and water-soluble carbohydrates in genotypes of Dactylis glomerata varying in summer dormancy.
作者信息
Volaire F, Norton M R, Norton G M, Lelièvre F
机构信息
Institut National de Recherche Agronomique, LEPSE, 2 place Viala, 34060 Montpellier, France.
出版信息
Ann Bot. 2005 May;95(6):981-90. doi: 10.1093/aob/mci102. Epub 2005 Mar 10.
BACKGROUND AND AIMS
Summer dormancy in perennial grasses has been studied inadequately, despite its potential to enhance plant survival and persistence in Mediterranean areas. The aim of the present work was to characterize summer dormancy and dehydration tolerance in two cultivars of Dactylis glomerata (dormant 'Kasbah', non-dormant 'Oasis') and their hybrid using physiological indicators associated with these traits.
METHODS
Dehydration tolerance was assessed in a glasshouse experiment, while seasonal metabolic changes which produce putative protectants for drought, such as carbohydrates and dehydrins that might be associated with summer dormancy, were analysed in the field.
KEY RESULTS
The genotypes differed in their ability to survive increasing soil water deficit: lethal soil water potential (Psi(s)) was -3.4 MPa for 'Kasbah' (although non-dormant), -1.3 MPa for 'Oasis', and -1.6 MPa for their hybrid. In contrast, lethal water content of apices was similar for all genotypes (approx. 0.45 g H(2)O g d. wt(-1)), and hence the greater survival of 'Kasbah' can be ascribed to better drought avoidance rather than dehydration tolerance. In autumn-sown plants, 'Kasbah' had greatest dormancy, the hybrid was intermediate and 'Oasis' had none. The more dormant the genotype, the lower the metabolic activity during summer, and the earlier the activity declined in spring. Decreased monosaccharide content was an early indicator of dormancy induction. Accumulation of dehydrins did not correlate with stress tolerance, but dehydrin content was a function of the water status of the tissues, irrespective of the soil moisture. A protein of approx. 55 kDa occurred in leaf bases of the most dormant cultivar even in winter.
CONCLUSIONS
Drought avoidance and summer dormancy are correlated but can be independently expressed. These traits are heritable, allowing selection in breeding programmes.
背景与目的
尽管多年生禾本科植物的夏季休眠具有提高其在地中海地区生存和持久性的潜力，但对其研究尚不充分。本研究旨在利用与这些性状相关的生理指标，对两种鸭茅品种（休眠的‘卡斯巴’、非休眠的‘绿洲’）及其杂交种的夏季休眠和脱水耐受性进行表征。
方法
在温室试验中评估脱水耐受性，同时在田间分析产生可能的干旱保护剂（如可能与夏季休眠相关的碳水化合物和脱水素）的季节性代谢变化。
关键结果
不同基因型在土壤水分亏缺增加时的存活能力存在差异：‘卡斯巴’（尽管是非休眠型）的致死土壤水势（Ψs）为-3.4MPa，‘绿洲’为-1.3MPa，其杂交种为-1.6MPa。相比之下，所有基因型顶端的致死含水量相似（约0.45g H₂O g干重⁻¹），因此‘卡斯巴’更高的存活率可归因于更好的干旱规避能力而非脱水耐受性。在秋播植物中，‘卡斯巴’的休眠程度最高，杂交种居中，‘绿洲’则无休眠。基因型的休眠程度越高，夏季的代谢活性越低，春季活性下降越早。单糖含量降低是休眠诱导的早期指标。脱水素的积累与胁迫耐受性无关，但脱水素含量是组织水分状况的函数，与土壤湿度无关。即使在冬季，最休眠品种的叶基部也存在一种约55kDa的蛋白质。
结论
干旱规避和夏季休眠相关但可独立表达。这些性状具有遗传性，可在育种计划中进行选择。
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