Hasanuzzaman Md, Shabala Lana, Brodribb Tim J, Zhou Meixue, Shabala Sergey
School of Land and Food, University of Tasmania, Private Bag 54, Hobart, Tas. 7001, Australia.
School of Biological Science, University of Tasmania, Private Bag 55, Hobart, Tas. 7001, Australia.
Funct Plant Biol. 2017 Feb;44(2):253-266. doi: 10.1071/FP16263.
Plant breeders are in the need for a convenient, reproducible, reliable and rapid screening methods to be used as a proxy for drought tolerance for a large number of genotypes. Addressing this need, we compared different physiological measures of stress in six barley (Hordeum vulgare L.) genotypes subjected to different drought treatments under glasshouse conditions. Genotypes were evaluated by measuring transpiration rate, quantum yield of PSII (chlorophyll fluorescence Fv/Fm ratio), SPAD chlorophyll meter reading, dry biomass and shoot water content. The accuracy of different methods for quantifying water stress tolerance was evaluated by measuring the rates of surviving and death in plants and leaves, and newly grown leaves after rewatering. In another experiment, the same genotypes were evaluated by applying 18% (w/v) of polyethylene glycol (PEG) to germinating seeds grown in paper rolls to induce osmotic stress, using relative root and shoot lengths as a measure of tolerance. The results suggest that transpiration measurements at the recovery stage could be the most sensitive method for separating contrasting genotypes. However, the method is time-consuming and laborious for large-scale screening. Chlorophyll content, dry biomass, shoot water content and stomatal density did not correlate with plant drought tolerance. At the same time, chlorophyll fluorescence Fv/Fm ratio showed a strong correlation with drought tolerance and could be recommended as suitable proxy for screening. Measuring relative root growth rate (length) using PEG-treated paper roll-grown seedlings also seems to be a highly suitable and promising method for screening a large number of genotypes in breeding programs.
植物育种者需要一种方便、可重复、可靠且快速的筛选方法，以便作为大量基因型耐旱性的替代指标。为满足这一需求，我们比较了在温室条件下对六种大麦（Hordeum vulgare L.）基因型进行不同干旱处理时的不同胁迫生理指标。通过测量蒸腾速率、PSII 的量子产量（叶绿素荧光 Fv/Fm 比值）、SPAD 叶绿素仪读数、干生物量和地上部含水量来评估基因型。通过测量植株和叶片的存活与死亡速率以及复水后新长出的叶片，评估了不同量化水分胁迫耐受性方法的准确性。在另一个实验中，通过对纸卷中生长的发芽种子施加 18%（w/v）的聚乙二醇（PEG）以诱导渗透胁迫，使用相对根长和茎长作为耐受性指标，对相同的基因型进行了评估。结果表明，恢复阶段的蒸腾测量可能是区分不同基因型最敏感的方法。然而，该方法对于大规模筛选来说耗时且费力。叶绿素含量、干生物量、地上部含水量和气孔密度与植物耐旱性无关。同时，叶绿素荧光 Fv/Fm 比值与耐旱性呈强相关，可推荐作为筛选的合适替代指标。使用 PEG 处理的纸卷培育幼苗测量相对根生长速率（长度）似乎也是在育种计划中筛选大量基因型的一种非常合适且有前景的方法。
