模拟酸雨对油菜(Brassica napus L.)生长、产量及品质的影响

Effects of simulated acid rain on the growth,yield and quality of rape

以油菜为供试材料,通过田间试验方法研究了酸雨对农作物生长、产量及品质的胁迫效应。研究结果表明,模拟酸雨胁迫对油菜的生长发育有较大的影响,具体表现为株高、叶面积生长受抑,叶单面鲜重明显降低,且在pH3.1时开始出现外观上的可见伤害;产量的分析结果表明,pH4.1可作为酸雨对油菜产量的影响阈限;品质特征指标分析结果表明,酸雨胁迫会导致油菜粗脂肪含量降低,使可溶性糖含量减少,而且随着酸度增强,粗脂肪与可溶性糖降低幅度越大;酸雨胁迫对可溶性蛋白质的影响阈限在pH5.1与pH4.1之间,对游离氨基酸总量的影响阈限在pH4.1与pH3.1之间,而对还原性糖、总酸度的影响阈限则在pH3.1与pH1.5之间,但以上各指标的确切阈值及酸雨对其影响的具体机理还有待进一步研究。

Acid rain is one of the most serious environmental problems worldwide. The effects of physiology and biochemistry of plants have been studied intensively at home and abroad, but few quality of crops, which plays a significant role in the agricultural ecosystem. Purpose of this simulated acid rain on the reports have focus on the study is to elucidate the influence of simulated acid rain on the growth, yield and quality of rape as the subject crop （Brassica napus L. ） through field experiment, so as to provide scientific basis for preventing and controlling the damage to crops from acid rain. According to acid deposition level in Nanjing area and referring to the related data from the Environmental Protection Agency, we obtained the simulated acid rain at pH 5.6 as the control index （CK）, by means of H2SO4 and HNO3 at the ratio of 5 to 1 as the concentration for the rain at the levels of pH 1.5, 3.1,4.1,5.1 and 5.6 measured by the PHS-25B acidometer （the Shanghai Precision Instruments Ltd. Co. ）. Referring to LU Xian-kai et al. about their similar design, we set up 15 small plots （4 m×5 m） in complete accordance with random group design principle, and all these plots were to the north of the NUIST, cultivated in mid September, 2005, with - 0.6 m spacing as a buffer zone, in order to prevent interference. The 15 plots were divided into 5 treatment groups, i.e., （ 1 ） CK （ pHS. 6）, （2） extreme AR （ pH 1.5 ）,（3） strong AR （pH 3.1 ）, （4） moderate AR（ pH 4.1 ）, （5） weak AR （pH 5.1 ）, each repeated in spraying three times. The seeds were well-grown of Qinyou 7 rape, disinfected for 10 min in HgCl2 solution at 1.0g/L concentration, followed by their repeated cleaning in deionized water. And they were sowed in an open field on 21 August, 2005 and interplanted into the plots on 16 September. Starting from the 3-leaf stage, small-size sprayers were used to water the plants at a 10-day interval, separately, with above 5 acid rains as natural precipitation. In each operation the spraying was stopped when water began dropping from leaves, in order to avoid the change in soil pH value. During the growth fertilizer was applied in time and also chemicals were sprayed according to crop disease and pests. In the experimental period, the rape growth and development were recorded and during flowering stage, measurement was made of plant height, leaf area, weight of 1 cm^2 fresh leaves and injured area in percentage etc. and also of the yield and quality during harvest. Results show that （ 1 ） simulated acid rain stress has considerable effect on the rape growth/development in such a way that the growth of the plant height and leaf area are suppressed and weight of fresh leaf per unite area is greatly declined with visible injury when pH 3. 1 operation is conducted; （2） yield analysis indicates that pH 4.1 concentration can be taken as the threshold value of the effect on rape yield; （3） study of quality indexes shows that acid rain stress can reduce the content of crude fat and of soluble sugar in the seeds, and with increased acidity their drop ranges will be enlarged. The stress influences the soluble protein at pH 5.1 -4.1, total free amino acid content at pH 4.1-3.1, as well as reduced sugar, and total acidity at pH 3.1 - 1.5. The specific values of above indexes as well as the mechanisms for their effect on acid rain concentration remain to be further explored.