铜胁迫和间作对玉米抗氧化酶活性及丙二醛含量的影响

为探讨红壤地玉米-豌豆间作种植模式对铜污染的响应机制,通过盆栽试验,研究了不同铜浓度(0、100、200、400、600 mg·kg-1)对玉米单作和玉米间作豌豆条件下植株生物量、铜含量、玉米抗氧化酶活性[超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)]及丙二醛含量(MDA)的影响。结果表明:在高Cu2+浓度(600mg·kg-1)胁迫下,间作玉米地上部和地下部干重较单作分别提高了20%和36.6%,与单作相比,随着Cu2+浓度升高(100、200、400、600 mg·kg-1),间作模式下玉米地上部铜含量分别降低了86.81%、44.57%、22.01%、11.11%,而地下部铜含量则分别提高了78.89%、24.79%、35.29%、13.31%,且差异均达到显著水平。在不同Cu2+浓度胁迫下,玉米叶和根中的SOD、POD、CAT活性和MDA含量均随着Cu2+浓度的增加而提高,仅Cu2+浓度达到600mg·kg-1时玉米体内的CAT活性有所下降。间作条件下玉米根的SOD活性较单作提高了48.07%~117.27%,间作玉米叶的SOD活性较单作提高了11.30%~46.90%。不同种植模式对Cu2+胁迫条件下的玉米POD活性均没有显著影响。在Cu2+(0~400mg·kg-1)胁迫下,间作玉米叶的CAT活性较单作均显著提高,分别提高了71.37%、140.40%、229.80%和161.75%,间作玉米根的CAT活性与单作无显著差异。间作玉米根的MDA含量较单作降低了26.13%~64.53%;在100、200 mg·kg-1Cu2+胁迫下,间作玉米叶的MDA含量较单作降低了0.30%和26.24%,但在400、600 mg·kg-1Cu2+胁迫下,间作玉米叶的MDA含量较单作提高了32.62%和93.51%。综上所述,在一定范围的Cu2+胁迫条件下,玉米根和叶中的抗氧化酶活性及MDA含量均有所提高来维持正常生长,间作模式在Cu2+胁迫下对玉米根和叶的抗氧化酶系统能起到一定的保护作用。     

Effects of humic acid on remediation of the nutritional deficiency of gerbera in hydroponic culture

Information is scant on the effect of humic acid (HA) on physiological, antioxidant and photosynthesis attributes of gerbera plants undergoing nutrient deficiency in culture solution. Gerbera plants cv. Malibu were grown in a factorial experiment based on a completely randomized design with 3 replications, using 3 different nutrient solutions [complete nutrient solution (NSc), 25% NSc (NS1), and 50% NSc (NS2)] treated with 2 levels of humic acid [0 (HA0) and 500 mg/l (HA1)].The interaction effect of HA and NS showed that HA improved the flower number in NSc, the transpiration in NS1+HA1, photosynthesis rate in NSc+HA1, stomatal conductance (gs) in NS2, mesophyll conductance of leaves in all NS levels and photosynthetic water use efficiency in NSc+HA1. The interaction effect of nutrient solution and HA on antioxidant activity was inconclusive, malondialdehyde content was the highest in NS2 and the lowest in NS1+HA1. The peroxidase activity increased in complete nutrient solution with and without HA and there were no differences among other treatments. Superoxide dismutase activity increased in NS1 and complete nutrient solution with HA and reached the highest in NSc. Humic acid was more effective in nutrient uptake, i.e., nitrogen, phosphorus, potassium, calcium, zinc, and iron (N, P, K, Ca, Zn, and Fe) in complete nutrient solution compared to NS1 and NS2. Conclusively, humic acid can compensate the nutrient deficiency stress of the culture solution in regards to protein synthesis, photosynthesis attributes regardless of the nutrient uptake of gerbera.     

水杨酸对西瓜抗冷性生理指标的影响

以1.0、2.0、3.0、3.5 mmol/L四种浓度的SA处理三叶一心西瓜幼苗,研究SA对西瓜幼苗抗冷性的影响。结果表明,SA可以增强西瓜幼苗的抗冷性,其中以1.0 mmol/L的效果为最好。经1.0 mmol/L SA处理的幼苗Pro含量、POD、CAT和ATP酶等3种保护酶的活性均比5 ℃对照有提高,MDA含量减少,并且SA可减缓低温下叶绿素含量的减少和增加膜透性。     

Effects of dietary polyunsaturated fatty acid/vitamin E (PUFA/tocopherol ratio on antioxidant defence mechanisms of juvenile gilthead sea bream (Sparus aurata L., Osteichthyes, Sparidae)

Lipid peroxidation, specifically polyunsaturated fatty acid (PUFA) oxidation is highly deleterious, resulting in damage to cellular biomembranes, and may be a principal cause of several diseases in fish including jaundice and nutritional muscular dystrophy. Tissue lipid PUFA content and composition are critical factors in lipid peroxidation, as is the level of endogenous antioxidant molecules such as vitamin E. The primary objective of the present study was the characterization of antioxidant systems in a cultured juvenile marine fish, gilthead sea bream (Sparus aurata) with the underlying aim to understand how to avoid oxidation problems that may cause pathologies and disease and so to enhance growth and quality of early ongrowing stages. Juvenile sea bream were fed diets having either high or low levels of fish oil and supplemented or basal levels of vitamin E with PUFA/vitamin E ratios ranging from 117±12 in the diet with low PUFA supplemented with vitamin E to 745±48 in the diet with high PUFA with no additional vitamin E. None of the diets had serious deleterious effects on growth or survival of the fish, but the different dietary regimes were effective in significantly altering the PUFA/vitamin E ratios in the fish livers with values ranging from 5.7±0.4 in fish fed the diet with low PUFA supplemented with vitamin E to 91.1±13.2 in fish fed the diet with high PUFA with no additional vitamin E. This had effects on the peroxidation status of the fish as indicated by the significantly altered levels of in vivo lipid peroxidation products measured in liver, with fish fed the diet rich in PUFA and low in vitamin E showing significantly higher values of thiobarbituric acid reactive substances (TBARS) and isoprostanes. The isoprostane levels generally followed the same pattern as the TBARS levels supporting its value as an indicator of in vivo oxidative stress in fish, as it is in mammals. However, few significant effects on antioxidant enzyme activities were observed suggesting that more severe conditions may be required to affect these activities such as increasing the PUFA/vitamin E ratio or by increasing peroxidative stress through the feeding of oxidized oils.     

灌浆结实阶段水分逆境对超级稻叶片丙二醛含量的影响

通过水份仪结合称重法人为控制土壤水分的盆栽试验,研究灌浆结实阶段水分逆境对不同类型超级稻品种叶片丙二醛(MDA)含量的影响.结果表明:水稻灌浆结实阶段对水分的敏感性较强,开花至花后30 d不同时段的水分逆境均导致叶片丙二醛含量显著增加,尤其花后30 d时叶片丙二醛含量较对照增加更为明显.不同水分条件下各品种倒二叶的丙二醛含量也均显著高于剑叶,水分逆境导致水稻叶片尤其是倒二叶的丙二醛含量显著升高,叶片膜脂过氧化程度增强,加速了叶片的衰老进程.不同品种由于对水分逆境响应的敏感性差异而受影响的程度不同,相对于普通杂交稻汕优63来说,超级稻品种受到的影响要小.     

土壤含水量对狗牙根叶片生理生态指标的影响

采用盆栽控水试验,研究了不同土壤含水量（水淹,23%,18%,13%,8%）对我国雅砻江库区重要植物物种狗牙根叶片光合色素、SOD活性、POD活性、脯氨酸和MDA含量变化的影响。结果表明:与对照（23%）相比,狗牙根受到淹水胁迫时叶绿素a,b的含量和光合效率有所下降,丙二醛含量有所升高,但是抗氧化酶活性以及脯氨酸含量的增大提高了植物对淹水胁迫的抵抗力。随着土壤含水量的减少,叶绿素a和b的含量、光合速率、SOD、POD活性和丙二醛含量先升高,随后逐渐降低。SOD和POD活性在8%时存在最低值,分别为33.10U/gFW和3.87U/gFW。Carotenoid/Chlorophyll（Car/Chl）比值在18%时达到最低值0.22,然后增大。脯氨酸（Pro）含量随胁迫程度呈明显的增大趋势,并在8%达到最大值0.31μg/gFW,说明干旱条件时狗牙根通过提高类胡萝卜素和脯氨酸含量来改善渗透调节能力,增强对干旱胁迫的抵抗能力和适应力。但严重的干旱胁迫（8%）导致了植物叶片的损伤。     

铈对盐胁迫下小麦种子萌发过程中生理指标的影响

以小麦为材料,在实验室模拟条件下,研究一定浓度的Ce（NH4）2（NO3）6对盐胁迫下小麦种子萌发的影响。发现当用浓度为0．8％NaCl溶液对小麦种子进行盐胁迫时,溶液中含10mg／L的Ce（NH4）2（NO3）6能够降低盐胁迫下的小麦种子可溶性糖和丙二醛含量,说明稀土元素铈在一定程度上能降低盐胁迫对小麦种子的危害。     

Oxidative Damage to Spodoptera fitura Cell Induced byα-Terthienyl

In this study, the oxidative damage of α-terthienyl （α-T） to the Spodoptera litura （SL） cell and its mechanism were investigated. MTT was used to compare the toxicity of α-T and rotenone to the SL cell. The output of malondialdehyde and relative content of glutathione were determined with 2-thiobarbituric acid （TBA） and 5, 5＇-dithio-bis （2-nitrobenzoic acid） （DTNB）, respectively. Transmission electron microscope （TEM） was employed to observe the influence of α-T on the membrane and organelle of the SL cell. The result showed that the IC50 value of α-T to the SL cell was 0.21 μg mL^-1, whereas the corresponding dose of rotenone was 12.25 μg mL^-1. The output of MDA had the same changing tendency with the concentration of α-T, whereas the content of GSH had the negative correlation with it. According to TEM, the cell membrane and karyotheca swelled and couldn＇t retain integrity, the intracellular substances leaked out, unidentified granules appeared in the SL cell. The mitochondria expanded, and the membrane and subcellular organelle were damaged severely. In this study, it was found that after oxidative damage induced by α-T, the output of MDA increased notably, whereas the relative content of GSH decreased. This indicated that the antioxidant ability of cell weakened. The result of TEM implied that the SL cell suffered from oxidative damage under the appointed dose.     

盐胁迫对四园林绿化树种叶片中叶绿素含量动态变化的影响

用不同浓度NaCl溶液处理一年生苗木乌柏(Sapium sebiferum(L．)Roxb)、栾树(Koelreuteria paniculata Laxm．)、黄栌(Pistacia chinensis Bunge．)、法桐(Platanus orientalis L．)，研究了四园林绿化树种叶片中叶绿素a、叶绿素b和总叶绿素含量的动态变化以及叶绿素与丙二醛、脯氨酸的相关性．结果表明，叶绿素a和总叶绿素含量均随盐胁迫程度的增加而降低，但叶绿素a和b降解的幅度以及叶绿素a／b值并不星现单一的变化趋势。相关分析表明．四树种总叶绿素含量与膜脂过氧化产物丙二醛含量负相关，说明盐胁迫下叶绿素的降解与膜脂过氧化存在着密切的关系．乌桕、栾树叶片中Chl与Pro含量星正相关；而法桐、黄栌则负相关，游离Pro的积累对叶绿素的合成与降解并未起直接作用。     

不同基因型水稻抽穗后衰老进程的比较研究

本实验对汕优63、J85、老来青等三种不同基因型水稻品种衰老过程中的生理生化指标进行了分析。结果表明,随着叶片衰老进程,剑叶中的叶绿素含量逐渐下降,丙二醛含量逐渐上升,而根系活力在抽穗后一直呈下降趋势。进一步比较三种不同类型水稻叶片的衰老进程,发现:(1)在外界环境一致的情况下,三种水稻在这三个指标上变化明显不同,其中粳稻老来青抗衰老程度最高,而最易衰老的是杂交稻汕优63;(2)汕优63在抽穗后5～10d内衰老最为迅速;(3)根系活力的下降早于叶片中与衰老有关的指标变化。这表明在衰老过程中,根系的衰老先于叶片。