模拟酸雨对小麦产量及籽粒蛋白质和淀粉含量及组分的影响

以宁麦13和徐麦31两种小麦(Triticum aestivum)品种为材料,通过盆栽试验研究了不同pH值酸雨对小麦产量和籽粒品质的影响。结果表明:模拟酸雨抑制了小麦的生长,减少了生物量的积累。pH值2.0酸雨处理后宁麦13的单穗粒数和单茎产量分别较对照下降了48.6%和56.7%,徐麦31则分别下降了31.2%和39.7%,差异显著。小麦籽粒主要营养成分对酸雨胁迫响应不同,酸雨处理提高了籽粒氨基酸、蛋白质含量,pH值2.0酸雨处理后,宁麦13和徐麦31小麦籽粒中氨基酸含量分别比对照高36.6%和30.9%,总蛋白含量分别比对照高20.6%和15.1%,均与对照差异显著。而小麦可溶性糖、淀粉和脂肪含量较对照降低,且总体表现为酸度增强变化幅度增大。不同蛋白组分也对酸雨胁迫反应不同,酸雨处理提高了籽粒中清蛋白和球蛋白含量,而降低了谷蛋白含量和谷/醇。pH值2.0的酸雨处理后,宁麦13和徐麦31的清蛋白含量较对照分别增加了13.1%和23.9%,但与对照差异不显著。酸雨胁迫降低了总淀粉和支链淀粉含量,宁麦13和徐麦31的pH值2.0酸雨处理总淀粉含量分别较对照下降了11.8%和20.2%,与对照差异显著,但对直链淀粉含量影响不明显。可见酸雨不仅影响小麦的产量,而且对品质也有明显影响。酸雨处理尽管提高了籽粒总蛋白含量,但降低了谷蛋白和谷/醇,降低了其加工品质。

Effects of different acidity acid rain on yield, protein and starch content and components in two wheat cultivars

Acid rain is a worldwide important environmental problem, and might be a long-term trouble due to the rapid development of industry. The south area of Yangtze River is one major acid rain region in China, where crop production is severely limited by acid rain interacted with acid red soil. Wheat is the third largest crop in China and the second largest crop in Jiangsu province. Both yield and quality of wheat are of importance to food security. Wheat may suffer from acid rain stress during the whole stage, but the later growth stage of grain filling is more critical in determining grain yield and quality. Although the growth and physiological characteristics of crops exposed to acid rain have been broadly studied, little is known about the effect of acid rain on wheat quality. Here, effects of acid rain on wheat yield and quality in wheat were investigated. Two wheat (Triticum aestivum) cultivars of Ningmai 13 and Xumai 31 were selected in a pot experiment in Pailou experiment station in Nanjing Agricultural University, Jiangsu Province, China. Two acid rain treatments, i.e. by spraying solution of pH 2.0 and pH 4.0 were implemented, and that at pH 6.0 was set as control. Acid rain inhibited the growth of wheat. The dry weight of leaf, stem and ear under both acid rain treatments all were reduced as compared with the control. Grain number per spike and yield per shoot of Ningmai 13 was significantly reduced by 48.6% and 56.9% due to acid rain of pH 2.0 as compared with pH 6.0, respectively, and those of Xumai 31 was significantly reduced by 31.2% and 40.1%. As to wheat grain quality, the influence of acid rain was more complicated. Contents of amino acids in wheat grain of Ningmai 13 and Xumai 31 under acid rain of pH 2.0 increased 36.6% and 30.9%, respectively, as compared with control. The content of total protein in grains of Ningmai 13 and Xumai 31 under acid rain of pH 2.0 increased 20.6% and 15.1%, respectively. Acid rain increased contents of albumin and globulin, while decreased content of glutenin and the ratio of glutenin to gliadin. Compared with the control, the albumin content at pH 2.0 in Ningmai 13 and Xumai 31 increased 13.1% and 23.9%, respectively, and the globulin content at pH 2.0 in Ningmai 13 and Xumai 31 increased 35.7% and 100%, respectively. The other protein was also increased by acid rain. While glutenin content at pH 2.0 in Ningmai 13 and Xumai 31 decreased 4.4% and 15.2%, respectively, as compared with the control. Acid rain decreased contents of soluble sugar, starch and fat in wheat grain. The total starch content of Ningmai 13 and Xumai 31 under acid rain of pH 2.0 decreased 11.8% (P<0.05) and 20.2% (P<0.05), respectively. Acid rain also reduced amylopectin content, but has little effect on amylose content. As a result, the ratio of amylopectin to amylose was also decreased, although the difference was not significant. It is concluded that acid rain influenced both wheat yield and quality. Although acid rain enhanced protein content, grain quality was negatively affected as exemplified by the decreased glutenin content and ratio of glutenin to gliadin and amylopectin to amylose.