干旱胁迫对不同倍性水平小麦品种形态、生理和生化特性的影响。
Effects of drought stress on morphological, physiological and biochemical characteristics of wheat species differing in ploidy level.
作者信息
Wang Jian Yong, Turner Neil C, Liu Ying Xia, Siddique Kadambot H M, Xiong You Cai
机构信息
State Key Laboratory of Grassland Agroecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
The UWA Institute of Agriculture, The University of Western Australia, M082, LB 5005 Perth, WA 6001, Australia.
出版信息
Funct Plant Biol. 2017 Feb;44(2):219-234. doi: 10.1071/FP16082.
Modern hexaploid wheat has several diploid and tetraploid predecessors. Morpho-physiological adaptation and the adaptation to drought of these different ploidy wheat species is largely unknown. To investigate the adaptation to drought stress, eight accesssions (two wild diploid (2n) accessions of Aegilops tauschii Coss., two domesticated diploid (2n) accessions of Triticum monococcum L., two domesticated tetraploid (4n) accessions of Triticum dicoccum Schrank ex Schübl. and two domesticated hexaploid (6n) accessions of Triticum aestivum L.) were exposed to three water regimes: (i) well-watered control (WW, 80% field capacity (FC)), (ii) moderate water stress (MS, 50% FC), and (iii) severe water stress (SS, 25% FC) from 30 days after sowing to maturity. The results showed that accession (A), water regime (W), and the interaction of A×W significantly affected yield, morpho-physiological traits, biochemical characteristics and biomass allocation. In the WW treatment, the aboveground biomass, ear biomass, grain yield and harvest index increased, whereas the number of spikes and spikelets per plant decreased from accessions of T. monococcum to T. dicoccum to T. aestivum. Across all accessions, yields decreased by 29% under moderate water stress and 61% under severe water stress. In all three water regimes, yields were positively correlated with photosynthesis (Pn) per plant (Pn×leaf area) at jointing and anthesis, largely the result of the differences and changes in leaf area. Water use efficiency for grain (WUEG) decreased by 2-6% in T. monococcum, but it increased by 15-16% in T. dicoccum and T. aestivum under drought stress. Analysis of the allometric relationships between aboveground biomass (MAB) and root biomass (Mroot) in the different species indicated that less biomass was allocated to roots with greater polyploidy while more biomass was allocated to roots with drought in A. tauschii, but not in the domesticated species. We conclude that domestication, selection and breeding of higher ploidy wheat has increased wheat yields primarily by increasing aboveground biomass and harvest index, increases that were maintained under water stress.
现代六倍体小麦有几个二倍体和四倍体的前身。这些不同倍性小麦品种的形态生理适应性和耐旱性在很大程度上尚不清楚。为了研究对干旱胁迫的适应性，选取了八个种质（两个野生二倍体（2n）节节麦（Aegilops tauschii Coss.）种质、两个驯化二倍体（2n）一粒小麦（Triticum monococcum L.）种质、两个驯化四倍体（4n）二粒小麦（Triticum dicoccum Schrank ex Schübl.）种质和两个驯化六倍体（6n）普通小麦（Triticum aestivum L.）种质），使其在三种水分条件下生长：（i）充分浇水对照（WW，80% 田间持水量（FC）），（ii）中度水分胁迫（MS，50% FC），以及（iii）重度水分胁迫（SS，25% FC），从播种后30天到成熟。结果表明，种质（A）、水分条件（W）以及A×W的相互作用对产量、形态生理性状、生化特性和生物量分配有显著影响。在WW处理中，从一粒小麦到二粒小麦再到普通小麦，地上生物量、穗生物量、籽粒产量和收获指数增加，而单株穗数和小穗数减少。在所有种质中，中度水分胁迫下产量下降29%，重度水分胁迫下产量下降61%。在所有三种水分条件下，产量与拔节期和开花期单株光合作用（Pn）（Pn×叶面积）呈正相关，这主要是叶面积差异和变化的结果。在干旱胁迫下，一粒小麦的籽粒水分利用效率（WUEG）下降了2 - 6%，而二粒小麦和普通小麦的WUEG增加了15 - 16%。对不同物种地上生物量（MAB）和根生物量（Mroot）之间的异速生长关系分析表明，随着多倍性增加，分配到根的生物量减少，而在节节麦中，干旱时分配到根的生物量增加，但在驯化物种中并非如此。我们得出结论，对更高倍性小麦的驯化、选择和育种主要通过增加地上生物量和收获指数提高了小麦产量，这些增加在水分胁迫下得以维持。
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