模拟硫酸型、硝酸型及其混合型酸雨对油菜生理特性、生长和产量的影响

为了了解我国酸雨污染由硫酸型向硫-硝酸复合型转变所引起的环境效应,以油菜(Brassicanapus)为供试材料,在大田试验条件下,系统研究了模拟硫酸型(SAR)、硝酸型(NAR)及其混合型(MAR)酸雨对农作物生理特性、生长和产量的影响。结果表明,3种酸雨胁迫均能抑制油菜生理、生长和产量形成,但不同类型的酸雨间的抑制效应存在差异。当pH≤4.1时,SAR、NAR、MAR能破坏油菜叶质膜系统、降低光合色素含量及光合速率,从而抑制作物的光合作用;当pH≤3.1时,油菜叶面积减小,叶受害百分率明显增加。pH=4.1可作为酸雨对油菜产量的影响阈值。在pH=7.0–1.5的酸度范围内,油菜叶片膜透性、丙二醛含量、叶受害百分率表现为NARMARSAR,光合速率、光合色素含量、叶面积及产量则表现出SARMARNAR的变化特征。当pH4.1时,3种酸雨处理间差异均不明显,pH≤3.1时,3种酸雨间的胁迫效应差异显著增加(p0.05),且酸度越强,差异越大,其变化趋势为NARMARSAR。说明NAR和MAR胁迫对油菜生理、生长及产量的抑制较大。

Effects of simulated sulfur-rich, nitric-rich and mixed acid rain on the physiology, growth and yield of rape (Brassica napus)

Aims Our objective was to investigate the effect of sulfur acid rain (SAR), nitric acid rain (NAR) and their mixture (MAR) on the physiology, growth and yield of the crop rape (Brassica napus).Methods Fifteen 4 m × 5 m plots were distributed stochastically for exploring SAR, NAR and MAR stress, with a roughly 0.6 m spacing between plots to avoid interference. We used three replicate treatments of pH = 7.0, 1.5, 3.1, 4.1 and 5.1 and examined growth and development at 5-day intervals from budding to the end of flowering (March 10 to April 25,2006). On April 12 for the peak period of flowering, we measured leaf cell membrane permeability, contents of malondialdehyde (MDA) and photosynthesis pigment in leaves, photosynthesis speed, leaf injury rate and leaf area as physiological and growth parameters. On May 10, we measured the yield index during the ripening stage.Important findings These kinds of acid rains can inhibit physiology, growth and yield with effects differing among treatments. At pH ≤ 4.1, SAR, NAR and MAR damage the membrane of rape leaves, decreasing photo-synthetic pigment content and photosynthetic speed, thereby diminishing photosynthesis of the crop. For pH ≤ 3.1, leaf area is decreased and the leaf injury rate increases greatly. The value of pH = 4.1 can be used as the threshold for impact on rape yield. Over the range of pH = 1.5-7.0, leaf membrane permeability, MDA content and leaf injury rate follow the pattern of NAR > MAR > SAR and for the photosynthetic speed, content of photosynthesis pigment, leaf area and yield the order is SAR > MAR > NAR. At pH > 4.1, the differences between these treatments of acid rain are insignificant. For pH ≤ 3.1, the stress differences become large (p < 0.05), with greater differences at stronger acidities, following the pattern NAR > MAR > SAR. This indicates the first two treatments have stronger inhibiting effects on the physiology, growth and yield of rape.