不同类型模拟酸雨对油菜营养品质的影响

采用完全随机区组设计方法,在大田试验条件下研究了混合模拟酸雨(MAR)、硫酸模拟酸雨(SAR)和硝酸模拟酸雨(NAR)对油菜营养品质的影响作用及其机制,旨在为防治酸雨对我国农业生产的影响提供科学依据.试验结果表明,在弱酸性条件下,3种不同类型酸雨均能促进油菜籽总游离氨基酸和可溶性蛋白质的合成,而在强酸性条件下,NAR和MAR对以上2种组分会有较强的抑制作用,且以NAB的抑制作用较明显.3种不同类型模拟酸雨作用下,油菜籽粗脂肪含量随着pH值的上升呈先增加后下降的变化趋势,其中在较强酸性条件下NAB和MAR即能抑制作物粗脂肪的合成,而SAR的影响明显不及前两者.随着酸雨酸度的增强,3种不同酸雨均能使油菜籽硫苷总量持续增加,且在较强酸性条件下NAB和MAR的促进作用影响较大.3种不同类型酸雨均能一定程度地降低作物油酸含量,但NAB在pH≤4.1时能较大地促进亚油酸、亚麻酸和芥酸的合成,从而使作物品质下降.     

Effects of cerium on growth and physiological mechanism in plants under enhanced ultraviolet-B radiation

Effect of cerium （Ce^3＋） on the growth, photosynthesis and antioxidant enzyme system in rape seedlings （Brassica juncea L.） exposed to two levels of UV-B radiation （T1： 0.15 W/m^2 and T2：0.35 W/m^2） was studied by hydroponics under laboratory conditions. After 5 d of UV-B treatment, the aboveground growth indices were obviously decreased by 13.2%-44. 1%（T1） and 21.4%-49.3% （T2）, compared to CK, and except active absorption area of roots, the belowground indices by 14.1%-35.6%（T1） and 20.3%-42.6% （T2）. For Ce＋UV-B treatments, the aboveground and belowground growth indices were decreased respectively by 4.1%-23.6%, 5.2% -23.3%（Ce＋T1） and 10.8%-28.4%, 7.0%-27.8%（Ce＋T2）, lower than those of UV-B treatments. The decrease of growth indices appeared to be the result of changes of physiological processes. Two levels of UV-B radiation induced the decrease in chlorophyll content, net photosynthesis rate, transpiration rate, stomatal conductance and water use efficiency by 11.2%-25.9%（T1） and 20.9%- 56.9%（T2）, whereas increase in membrane permeability and activities of antioxidant enzymes including superoxide dismutase（SOD）, catalase （CAT） and peroxidase （POD） by 6.9%, 22.8%, 21.5%, 9.5%（T1） and 36.6%, 122.3%, 103.5%, 208.9%（T2）, respectively. The reduction of the photosynthetic parameters in Ce＋UV-B treatments was lessened to 3.2%-13.8%（Ce＋T1） and 4.9%-27.6%（Ce＋T2）, and the increase of membrane permeability and activities of antioxidant enzymes except POD in the same treatments were lessened to 2.4%, 8.4%, 6.6%（Ce＋T1） and 30.1%, 116.7%, 75.4%（Ce＋T2）. These results indicate that the regulative effect of Ce on photosynthesis and antioxidant enzymatic function is the ecophysiological basis of alleviating the suppression of UV-B radiation on growth of seedlings. Furthermore, the protective effect of Ce on seedlings exposed to TI level of UV-B radiation is superior to T2 level.     

Response of peroxidase and catalase to acid rain stress during seed germination of rice, wheat, and rape

Seed germination of plants with various acid-resistance display different responses to acid rain. To understand the reason why such differences occur, the effects of simulated acid rain (pH 2.5–5.0) on the activities of peroxidase (POD) and catalase (CAT) during seed germination of rice (O. sativa), wheat (T. aestivum), and rape (B. chinensis var. oleifera) were investigated. Results indicated that the maximum change in activities of CAT and POD by acid rain treatment with different acidity and time in relation to the referent treatment without acid rain, was in the order: rice (28.8%, 31.7%) < wheat (34.7%, 48.3%) < rape (79.3%, 50.0%). The pH level for which the treatment with acid rain did not cause significant difference (p < 0.05) was in the order: rice (3.5).wheat (4.0).rape (5.0). Moreover, the change in activity of POD was higher than that of CAT, which showed that POD was more sensitive to acid rain stress than CAT. The difference in the ability of POD and CAT in removing free radicals was one reason why the germination indexes of these three species behaved differently. __________ Translated from Environmental Science, 2005, 26(6): 123–125 [译自: 环境科学]     

模拟酸雨影响下红壤中硼的释放特征

为了探明酸雨对红壤中硼释放的影响,了解土壤缺硼机制,采用室内模拟酸雨淋溶土柱的方法,研究了酸雨作用下红壤中硼的释放特征.结果表明,酸雨加速了红壤中硼的淋溶损失.酸雨作用下红壤中硼的释放随淋溶量的变化具有初期阶段减小,中期阶段显著增大和后期阶段又减小的阶段性特点.模拟酸雨的pH值越低,硼的释放量越高.酸雨对硼释放的这种促进作用,一般表现为中期阶段的影响要大于初期和后期阶段的影响.淋出液中硼含量的动态变化与pH值的变化成负相关关系.供试土壤不同,硼的释放强度和释放特征存在一定的差异性,硼的释放强度和特点明显受土壤硼的背景值和土壤对酸缓冲能力的影响.     

臭氧和模拟酸雨对冬小麦气体交换、生长和产量的复合影响

为探明酸雨和臭氧(O3)对作物是否存在复合影响,运用田间原位开顶气室研究了pH4.0模拟酸雨(SAR)和O3对冬小麦气体交换、生长和产量的影响.该实验包括3种处理:CF处理采用经活性炭过滤后的空气,作为对照;CF100处理采用经活性炭过滤后的空气加人恒定浓度为100 nL·L-1的O3;CF100 SAR处理为在CF100的基础上对冬小麦喷施pH 4.0模拟酸雨,喷施量为150 mL·m-2,每10d一次.结果表明:①CF100和CF100 SAR组冬小麦叶片细胞膜系统受到破坏,光合色素含量和气体交换参数降低,抑制了作物生长,导致生物量和产量下降.与CF相比,CF100和CF100 SAR处理下冬小麦产量分别降低了68.2%和63.6%;②与CF100组相比,CF100 SAR组对冬小麦细胞膜系统和叶绿素a含量产生显著的复合影响(p＜0.05),而对叶绿素b和类胡萝卜素含量、气体交换、小麦生长、生物量和产量的复合影响不显著.     

模拟酸雨对土壤酸性磷酸酶活性的影响及机理

通过恒温恒湿连续培养的方法,研究了外源酸雨对土壤pH值、酸性磷酸酶活性的影响,同时运用紫外差光谱和荧光光谱对其机理进行了探讨.结果表明,酸雨通过改变土壤pH值而影响酶活性,pH6.66的近中性土壤酶活性呈现激活-抑制的变化过程;而pH4.61的酸性土壤酶活性持续下降.溶液构象研究表明,pH值是通过改变酶的肽链构象、氨基酸残基微环境而影响其活性的.     

模拟酸雨对亚热带三个树种凋落叶分解速率及分解酶活性的影响

利用凋落物袋法研究了模拟酸雨对中国亚热带地区3个典型树种杉木(Cunninghamia lanceolata)、香樟(Cinnamomum camphora)、银杏(Ginkgo biloba)凋落叶分解速率及酶活性的影响.酸雨分别设置为重度酸雨(pH=2.5)、中度酸雨(pH=4.0)、对照处理(pH =5.6)3个梯度.试验结果表明:酸雨胁迫会抑制凋落叶的分解,且随着酸雨强度的增强,抑制作用更明显.杉木、香樟、银杏3个树种对照处理下周转期分别比中度酸雨短33％、43％、14％,比重度酸雨短44％、52％、17％.3种分解酶对酸雨胁迫的表现不同,脲酶和纤维素酶表现为一定的抑制作用,基本呈现为对照处理(pH=5.6)＞中度酸雨(pH=4.0)＞重度酸雨(pH=2.5),与凋落物的分解速率排列情况一致,蔗糖酶在酸雨胁迫下反而有激活的趋势,表现为重度酸雨(pH=2.5)＞中度酸雨(pH =4.0)＞对照处理(pH=5.6).不同树种对酸雨胁迫的影响有一定的差异性,针叶树种杉木受影响最大,阔叶树种香樟和银杏受影响较小,银杏的抗酸性较强,且针叶树种的分解速率比阔叶树种慢.脲酶和纤维素酶对凋落叶的分解贡献较大,而蔗糖酶的影响相对较小.酶活性与季节有较大的关系,夏季活性相对偏高,冬季活性相对偏低.     

Effects of simulated acid rain on root growth of Cunninghamia lanceolata and Schima superba saplings planted in acidified soil

Results from pot culture (with one-year old Cunninghamia lanceolata and Schima superba) are described. It was found that the biomass production and elongation of C. lanceolata was seriously inhibited at pH 2.0 rain, but for S. superba, was not affected markedly. When pH values of experimental rain were higher than 2.0, the root growth of both species was not adversely affected. Aluminium had already accumulated to some degrees in the roots of both trees, and started to affect the root growth of C. lanceolata at pH 2.0 rain. The soil chemistry was also examined. Increased acidity of experimental rain increased the leaching of Ca and Mg. The Al/Ca mol ratio increased from 0.3 to 0.9 in top soil, and in rhizosphere to 1.5 when the pH values of simulated acid rain were 4.5 to 2.0. In this experiment, NO3- fertilization effect was discovered.     

模拟酸雨对福州平原稻田土壤真菌群落结构及多样性影响

酸雨已成为全球农业、环境和生态领域关注的重要问题之一.为了探讨酸雨对稻田土壤真菌多样性的影响,了解真菌群落结构变化与酸雨胁迫之间的关系.本文以福州平原稻田为试验场所,根据福州市近年来的酸雨成分,配置不同酸度的模拟酸雨,计算出喷淋量,并于水稻秧苗移栽后每隔7 d喷淋一次酸雨,直至水稻收割.当水稻收获时,采集土壤样品分析不同酸度模拟酸雨处理下早、晚稻土壤真菌群落组成及其丰度.结果表明:①模拟酸雨处理改变了稻田土壤真菌的相对丰度、多样性及群落组成,且不同处理中真菌的优势菌属及相对丰度也具有差异;②早稻3个模拟酸雨处理组均使稻田土壤真菌多样性降低,在晚稻生长期,pH=2.5和pH=3.5处理使稻田土壤真菌多样性降低,而pH=4.5处理则使真菌多样性显著升高;③模拟酸雨处理使Paranamyces、刺座霉属(Volutella)、镰刀菌属(Fusarium)的相对丰度显著降低,同时也出现了少量Monographella、Hygrocybe、Acremonium等对照组中不存在的菌属;④早、晚稻pH=4.5处理组与对照组之间真菌的物种多样性及群落结构差异均最大;⑤环境因子能够影响土壤中真菌的相对丰度并改变土壤碳组分,其中,真菌Westerdykella(韦斯特壳属)的相对丰度与稻田土壤电导率(EC)呈显著负相关(p0.01),Psilocybe的相对丰度与稻田土壤微生物量碳(MBC)呈显著正相关(p0.01).     

土壤-植物系统中模拟酸雨与Cd复合污染的短期环境效应--黄豆盆栽试验

通过盆栽实验,研究了在黄豆(Glycne max)的一个生长周期内,模拟酸雨与Cd复合污染对土壤基本性质的影响,模拟酸雨作用下土壤-植物系统中Cd的迁移转化规律以及模拟酸雨与Cd复合污染对黄豆生长与生理特性的影响,探讨了土壤-植物系统中这种复合污染的短期环境效应.结果表明,短期内模拟酸雨和Cd污染对土壤-植物系统都有致害作用,但Cd污染的效应大于模拟酸雨的效应,模拟酸雨与Cd复合污染环境效应大于这2种污染物的单因素效应,且表现出明显的协同作用.在本试验条件下,pH值为3.5的模拟酸雨和20 mg·kg-1Cd的处理组合对土壤-植物系统的危害最严重.尽管在短期内,协同作用仅在土壤交换态Cd含量、黄豆茎和根中的Cd含量这3项指标上得到一定程度的体现,但这种复合污染的化学机制和环境效应值得关注,这2种污染物长时期共同作用对土壤-植物系统的影响也值得深入研究.     

模拟酸雨对水稻叶片质膜H~+-ATPase活性与矿质元素含量的影响

采用水培法研究模拟酸雨(p H=5.0、3.5、2.5)对水稻叶片质膜H+-ATPase活性与矿质元素含量的影响.结果显示:与对照(CK)相比,酸雨处理5 d(胁迫期)后,p H=5.0组质膜H+-ATPase活性与活化能、K+、Ca2+、Mg2+含量均无显著变化,仅细胞渗透势下降.p H=3.5酸雨导致细胞渗透势、K+含量下降,质膜H+-ATPase活性、H+-ATPase活化能、Ca2+含量明显上升,Mg2+含量无显著变化.p H=2.5组H+-ATPase活性、细胞渗透势和K+、Mg2+含量明显下降,H+-ATPase活化能和Ca2+含量上升,表明矿质元素含量不仅受H+-ATPase活性的调控,还与酸雨强度和离子价态有关.经5 d恢复(恢复期)后,p H=5.0组各指标均恢复到CK水平,p H=3.5组除细胞渗透势外均恢复至CK水平,p H=2.5处理组各指标虽未达到CK水平,但较胁迫期有所恢复.表明K+、Ca2+、Mg2+含量受H+-ATPase活性的调节,且恢复效果受酸雨强度影响.     

模拟酸雨对水稻叶片质膜H+-ATPase活性与胞内Ca2+浓度的影响

在水培条件下研究了模拟酸雨(pH=2.5～5.5)对水稻叶片胞内Ca2+浓度和质膜H+-ATPase活性的影响.结果表明:与对照组(CK)相比,酸雨处理5 d(胁迫期)后,pH=5.5和5.0处理组的水稻叶片胞内H+浓度、质膜H+-ATPase活性、胞内Ca2+浓度、质膜Ca2+-ATPase活性无显著变化;pH=4.0和3.5处理组各指标显著升高,且H+-ATPase活性随Ca2+浓度升高而上升;pH=3.0和2.5处理组各指标显著降低,此时胞内Ca2+缺失,对H+-ATPase活性的调节作用受到限制.经正常条件培养5 d(恢复期)后,pH=4.0和3.5处理组各指标均恢复至CK的处理水平,表明H+-ATPase活性受到Ca2+调控已恢复到正常;pH=3.0和2.5处理组的Ca2+浓度高于CK及胁迫期,H+-ATPase活性低于CK但高于胁迫期,表明H+-ATPase活性受Ca2+调控得到部分恢复.因此,酸雨胁迫下胞内Ca2+对质膜H+-ATPase活性有一定调节作用,且受酸雨强度的制约.