磷化氢、二氧化碳混合气体对腐食酪螨成螨的生物学效应

本文研究结果表明：腐食酪螨Ｔｙｒｏｐｈａｇｕｓｐｕｔｒｅｓｃｅｎｔｉａｅ（Ｓｃｈｒａｎｋ）成螨在０％、８％、１６％（容积比）ＣＯ２气体中耗氧量随ＣＯ２浓度的增加而增加,当在３２％、６４％ＣＯ２气体中,该成螨的耗氧量反倒低于其在正常大气中的耗氧量。在０％、８％、１６％、３２％、６４％ＣＯ２与０．０５ｍｇ／ＬＰＨ３混合气体中该成螨对ＰＨ３的吸收量分别为１．１１±０．９２、１．７９±０．５６、５．１４±１．１３、７．６０±１．８０、８．０８±０．８５μｇ／ｈｒ’ｇ,在同一ＣＯ２浓度条件下试螨对ＰＨ３的吸收量在高浓度ＰＨ３（０．４５ｍｇ／Ｌ）中明显大于在低浓度ＰＨ３（０．０５ｍｇ／Ｌ）中,但ＰＨ３吸收量的增加倍数远远低于ＰＨ３浓度的增加倍数。ＰＨ３对该螨过氧化氢酶的抑制体内酶高于离体酶,细胞色素ｃ氧化酶受ＰＨ３抑制则相反。被ＰＨ３抑制的过氧化氢酶和细胞色素Ｃ氧化酶活性恢复时间分别为二周和一周。本文还对ＰＨ３的可能杀螨机理及ＣＯ２在此过程中的作用进行了讨论     

高CO2浓度下西花蓟马和花蓟马对虫螨腈和唑虫酰胺的响应比较

【目的】比较不同CO2浓度下虫螨腈和唑虫酰胺对西花蓟马Frankliniella occidentalis和花蓟马F. intonsa成虫的毒力以及体内保护酶和解毒酶等酶活性的影响,对未来高CO₂浓度下进一步研究蓟马对虫螨腈和唑虫酰胺的抗性管理具有一定的指导意义,以便及时做出害虫管理策略的调整。【方法】采用浸渍法测定正常CO₂浓度(400 μL/L)和高CO₂浓度(800 μL/L)环境下虫螨腈和唑虫酰胺对两种蓟马成虫的毒力［致死中浓度(LC₅₀值)和亚致死浓度(LC₂₅值)］;通过酶活性分析测定这两种CO₂浓度下LC₂₅浓度虫螨腈和唑虫酰胺处理48 h后这两种蓟马成虫体内保护酶［超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase, POD)和过氧化氢酶(catalase, CAT)］,解毒酶［羧酸酯酶(carboxylesterase, CarE)、谷胱甘肽S-转移酶(glutathione S-transferase, GST)和细胞色素P450(cytochrome P450 enzyme system, CYP450)］以及乙酰胆碱酯酶(AChE)的活性。【结果】800 μL/LCO₂下虫螨腈在48 h内对西花蓟马和花蓟马成虫的LC50值分别为1.33和0.37 mg/L,分别是400 μL/LCO₂下的0.68和0.66倍; LC₂₅值分别为0.60和0.24 mg/L, 分别为400 μL/L CO₂下的0.61和0.83倍。800 μL/L CO₂下唑虫酰胺在48 h内对西花蓟马和花蓟马成虫的LC₅₀值分别为1 002.64和247.66 mg/L,分别是400 μL/L CO₂下的0.98和0.78倍; LC₂₅值分别为368.77和146.10 mg/L, 分别是400 μL/LCO₂下的2.44和1.21倍。在800 μL/L CO₂下,LC₂₅浓度虫螨腈和唑虫酰胺处理48 h后两种蓟马成虫体内测试的各种酶活性(CYP450除外)均高于400 μL/L CO₂下的;两个CO₂浓度下西花蓟马成虫体内SOD, POD,CAT以及AChE活性均显著高于花蓟马成虫体内的相应酶活性。两个CO₂浓度下,经LC₂₅浓度唑虫酰胺处理后,两种蓟马成虫体内的3种保护酶活性(400 μL/L CO2下花蓟马SOD活性除外)均显著高于对照(含0.1%吐温-80的蒸馏水处理),且800 μL/L CO₂下西花蓟马成虫体内SOD和CAT活性均最高,分别为39.74±1.59和37.93±1.31 U/mg pro。两个CO₂浓度下,LC₂₅浓度虫螨腈和唑虫酰胺处理48 h后,西花蓟马成虫体内CarE活性较对照显著降低,而花蓟马成虫体内CarE活性高于对照,其中,经唑虫酰胺处理后达到显著差异;同时两种蓟马成虫体内AChE活性较对照均显著提高。【结论】高CO₂浓度增强了杀虫剂对西花蓟马和花蓟马的毒杀效果,花蓟马对这两种杀虫剂的敏感性强于西花蓟马,且西花蓟马对这两种杀虫剂的适应能力强于花蓟马。     

开放式空气CO2浓度增高条件下旱地土壤气体CO2浓度廓线测定

设计了一套适合于FACE(free-air CO₂ enrichment)平台的旱地土壤气体CO₂浓度廓线测定方法,并将其应用于田间实验.在江苏省无锡市郊区具有太湖地区典型水稻土的稻麦轮作农田,对FACE和对照麦田以及裸土0～30cm土层的土壤气体CO₂浓度廓线进行了观测研究.结果表明,所采用的方法满足进行旱地农田土壤气体CO₂浓度廓线研究的要求;在0～30cm土层中,上层土壤气体中的CO₂向上垂直扩散要比下层土壤快;在作物旺盛生长期,大气CO₂浓度升高200±40μmol·mol^-1使0～30cm土层的土壤气体CO₂浓度显著提高14%±5%(t检验P<0.001).     

大气CO2浓度增加与氮肥对棉花生物量、氮吸收量及土壤脲酶活性的影响

试验设置半开顶式CO₂人工气候室,研究了不同CO₂浓度处理(360、540 μmol·mol^-1)与施氮(N)量(0、150、300 和450 kg·hm^-2)对棉花干物质的积累与分配、氮素吸收量及土壤脲酶活性的影响.多样性指数和主成分分析表明: 各施N水平下,CO₂浓度增加下棉花蕾、茎、叶和整株的总干物质积累量显著增加;2个CO₂浓度下,300 kg·hm^-2-N (N₃₀₀)处理棉花蕾、茎、叶、根及整株干物质量显著高于其他3个N肥处理,合理的氮肥施用可显著提高棉花干物质积累量.棉花蕾和茎的氮素吸收量受CO₂浓度影响显著,与360 μmol·mol^-1CO₂浓度相比,CO₂浓度为540 μmol·mol^-1条件下蕾和茎的氮含量显著增加,其中N₃₀₀处理下蕾的氮含量最高,N₁₅₀和N₃₀₀处理茎的氮含量高于N₀和N₄₅₀处理;叶的氮素吸收量受CO₂和N的交互作用影响显著,在N₀、N₁₅₀、N₃₀₀处理下,540 μmol·mol^-1CO₂浓度下叶的氮含量增加;棉花根的氮素吸收量受施N的影响显著,540 μmol·mol^-1CO₂浓度下根的氮含量随着施N量的增加显著增加.总体上,540 μmol·mol^-1CO₂浓度下棉花的氮素吸收量高于360 μmol·mol^-1 CO₂浓度,各CO₂和N组合处理下,棉花各器官的氮素积累量蕾铃最高,叶片居中,其次是茎秆,根系最低.各施N水平下,两个土层的土壤脲酶活性随着CO₂浓度升高而显著增加;不同CO₂浓度处理下,0~20 cm土层土壤脲酶活性随着施N量的增加而增加,20～40 cm土层N₃₀₀处理下的土壤脲酶活性高于其他N肥处理;CO₂和N互作下,0~20 cm土层土壤脲酶活性的平均值显著高于20~40 cm土层.大气CO₂浓度为540 μmol·mol^-1、氮肥施用量为300 kg·hm^-2可显著提高棉花干物质积累量和氮素吸收量.     

CO2浓度升高对西花蓟马和花蓟马成虫体内解毒酶和保护酶活性的影响

【目的】阐明大气CO₂浓度升高对外来入侵昆虫西花蓟马Frankliniella occidentalis及其本地近缘种花蓟马F. intonsa的影响机制。【方法】测定和分析了CO₂人工气候箱内不同CO₂浓度（400 μL/L和800 μL/L）下饲养3代的这两种蓟马体内3种解毒酶［羧酸酯酶（CarE）、乙酰胆碱酯酶（AchE）和微粒体多功能氧化酶(MFO）］和3种保护酶［超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD）］的活性。【结果】西花蓟马成虫体内的CarE, AchE, MFO, CAT和POD酶活性随着CO₂浓度的升高而显著上升（P＜0.05）,其中800 μL/L CO₂浓度下CarE和MFO酶活性分别比400 μL/L CO₂浓度下增加了24.78%和16.05%;800 μL/L CO2浓度下花蓟马成虫体内的CarE, MFO和CAT酶活性显著高于400 μL/L CO₂浓度下花蓟马成虫体内的相应酶活性,而AchE和POD酶活性在两种CO2浓度间差异不显著（P＞0.05）。800 μL/L CO₂浓度下西花蓟马和花蓟马成虫体内的SOD酶活性均显著低于400 μL/L CO₂浓度下的相应蓟马酶活性（P＜0.05）,分别下降了65.22%和42.20%。【结论】CO₂浓度升高是导致两种蓟马成虫体内CarE,MFO和SOD酶活性上升的主要原因,而AchE, CAT和POD酶活性的变化主要受蓟马种类的影响。两种蓟马可能通过改变体内解毒酶或保护酶的活性来适应高浓度CO₂的环境。     

大气CO2浓度增加与氮肥对棉花生物量、氮吸收量及土壤脲酶活性的影响

试验设置半开顶式CO₂人工气候室,研究了不同CO₂浓度处理(360、540 μmol·mol^-1)与施氮(N)量(0、150、300 和450 kg·hm^-2)对棉花干物质的积累与分配、氮素吸收量及土壤脲酶活性的影响.多样性指数和主成分分析表明: 各施N水平下,CO₂浓度增加下棉花蕾、茎、叶和整株的总干物质积累量显著增加;2个CO₂浓度下,300 kg·hm^-2-N (N₃₀₀)处理棉花蕾、茎、叶、根及整株干物质量显著高于其他3个N肥处理,合理的氮肥施用可显著提高棉花干物质积累量.棉花蕾和茎的氮素吸收量受CO₂浓度影响显著,与360 μmol·mol^-1CO₂浓度相比,CO₂浓度为540 μmol·mol^-1条件下蕾和茎的氮含量显著增加,其中N₃₀₀处理下蕾的氮含量最高,N₁₅₀和N₃₀₀处理茎的氮含量高于N₀和N₄₅₀处理;叶的氮素吸收量受CO₂和N的交互作用影响显著,在N₀、N₁₅₀、N₃₀₀处理下,540 μmol·mol^-1CO₂浓度下叶的氮含量增加;棉花根的氮素吸收量受施N的影响显著,540 μmol·mol^-1CO₂浓度下根的氮含量随着施N量的增加显著增加.总体上,540 μmol·mol^-1CO₂浓度下棉花的氮素吸收量高于360 μmol·mol^-1 CO₂浓度,各CO₂和N组合处理下,棉花各器官的氮素积累量蕾铃最高,叶片居中,其次是茎秆,根系最低.各施N水平下,两个土层的土壤脲酶活性随着CO₂浓度升高而显著增加;不同CO₂浓度处理下,0~20 cm土层土壤脲酶活性随着施N量的增加而增加,20～40 cm土层N₃₀₀处理下的土壤脲酶活性高于其他N肥处理;CO₂和N互作下,0~20 cm土层土壤脲酶活性的平均值显著高于20~40 cm土层.大气CO₂浓度为540 μmol·mol^-1、氮肥施用量为300 kg·hm^-2可显著提高棉花干物质积累量和氮素吸收量.     

大气CO2浓度升高对香蕉光合作用及光合碳循环过程中叶氮分配的影响

生长在高CO₂浓度(700±5μl·L^-1)1周的香蕉叶片,其光合速率(Pn,μmol·m^-2·s^-1)为5.14±0.32,较生长在大气CO₂浓度(356±301μl·L^-1)的高22.1%,而生长在较高CO₂浓度下8周,叶片Pn较生长在大气CO₂浓度的低18.1%,表现香蕉叶片对较长期高CO₂浓度的驯化和光合作用抑制.生长在高CO₂浓度的香蕉叶片有较低光下呼吸速率(R_d),而不包括光下呼吸的CO₂补偿点则变幅较小.最大羧化速率(Vcmax)和电子传递速率(J)分别较生长在大气CO₂浓度的低30.5%和14.8%,根据气体交换速率计算的表观量子产率(α,mol CO₂·mol^-1光量子),生长在较高CO₂浓度下8周的叶片为0.014±0.01,而生长在大气CO₂浓度下的为0.025±0.005.较高CO₂浓度下叶片的表观量子产率降低44%.光能转换效率electrons·quanta^-1)亦从0.203降低至0.136.生长在较高CO₂浓度下香蕉叶片的叶氮在Rubicos分配系数(PR)、叶氮在生物力能学组分分配系数(P_B)和叶氮在光捕组分的分配系数(P_L)均较生长在大气CO₂浓度低,表明在高CO₂浓度下较长期生长(8周)的香蕉叶片多个光合过程受抑制,光合活性明显降低.     

粳稻生育后期剑叶光合日变化和光合色素对大气CO2浓度和温度升高的响应——FACE研究

为研究水稻叶片光合色素和光合日变化对大气CO₂浓度和气温升高的响应,我们采用在开放空气中控制升高CO₂浓度和温度的方法,以常规粳稻南粳9108为试验材料,设置了环境CO₂和高大气CO₂浓度(增加200 μmol·mol^-1)、环境温度和增温(增加1～2 ℃)交互的4个处理,测定了灌浆中期和后期水稻剑叶的光合日变化特征和光合色素含量.结果表明: 水稻剑叶净光合速率(P_n)为双峰曲线,发生了光合“午休”现象;大气CO₂浓度升高提高了剑叶P_n,灌浆中期和后期平均分别增加了47.6%和39.1%;高温有降低P_n的趋势,但相关性未达到显著水平.大气CO₂浓度和温度升高导致水稻剑叶生育后期气孔导度(g_s)平均分别降低了17.0%和11.8%.高CO₂浓度水稻剑叶生育后期蒸腾速率(T_r)、叶绿素a、叶绿素b、类胡萝卜素、总叶绿素和叶绿素a/b值显著降低,平均降幅分别为5.9%、50.4%、21.3%、41.4%、39.4%和21.4%,明显增加了剑叶水分利用率(WUE),平均增幅达47.9%.与之相反,生育后期增温使水稻剑叶T_r增加了10.2%,使WUE平均降低了20.4%.综上所述,大气CO₂浓度升高对粳稻生育后期剑叶P_n、g_s和光合色素含量的影响明显大于增温效应.因此,应重视大气CO₂浓度和温度对水稻光合作用和光合色素的综合效应,减弱增温的负效应.     

粳稻生育后期剑叶光合日变化和光合色素对大气CO2浓度和温度升高的响应——FACE研究

为研究水稻叶片光合色素和光合日变化对大气CO₂浓度和气温升高的响应,我们采用在开放空气中控制升高CO₂浓度和温度的方法,以常规粳稻南粳9108为试验材料,设置了环境CO₂和高大气CO₂浓度(增加200 μmol·mol^-1)、环境温度和增温(增加1～2 ℃)交互的4个处理,测定了灌浆中期和后期水稻剑叶的光合日变化特征和光合色素含量.结果表明: 水稻剑叶净光合速率(P_n)为双峰曲线,发生了光合“午休”现象;大气CO₂浓度升高提高了剑叶P_n,灌浆中期和后期平均分别增加了47.6%和39.1%;高温有降低P_n的趋势,但相关性未达到显著水平.大气CO₂浓度和温度升高导致水稻剑叶生育后期气孔导度(g_s)平均分别降低了17.0%和11.8%.高CO₂浓度水稻剑叶生育后期蒸腾速率(T_r)、叶绿素a、叶绿素b、类胡萝卜素、总叶绿素和叶绿素a/b值显著降低,平均降幅分别为5.9%、50.4%、21.3%、41.4%、39.4%和21.4%,明显增加了剑叶水分利用率(WUE),平均增幅达47.9%.与之相反,生育后期增温使水稻剑叶T_r增加了10.2%,使WUE平均降低了20.4%.综上所述,大气CO₂浓度升高对粳稻生育后期剑叶P_n、g_s和光合色素含量的影响明显大于增温效应.因此,应重视大气CO₂浓度和温度对水稻光合作用和光合色素的综合效应,减弱增温的负效应.     

大气CO2浓度升高对八宝景天生长及光合生理的影响

利用开顶式气室(OTC)系统,设正常大气CO₂浓度和CO₂浓度升高200 μmol·mol^-12个CO₂浓度处理,模拟大气CO₂浓度升高对八宝景天光合生理和生长发育的影响.结果表明: 大气CO₂浓度升高使八宝景天叶片上、下表皮气孔密度分别显著下降16.1%和16.7%,使叶片维管束增粗,导管增多,靠近上表皮细胞增大;CO₂浓度升高可以显著增加傍晚时八宝景天叶片光合色素含量,使夜间净光合速率、气孔导度和蒸腾速率显著增加.初花期傍晚,CO₂浓度升高使叶片苹果酸含量显著下降64.0%,纤维素含量显著增加20.8%.盛花期清晨,CO₂浓度升高使叶片苹果酸含量显著增加27.0%,对糖类物质含量影响不显著,植株的分枝数、单株茎质量和单株总生物量显著增加.CO₂浓度升高可以促进八宝景天光合作用,有利于植株生长.     

温湿度对神泽氏叶螨发育历期和产卵量的影响

将神泽氏叶螨Tetranychus kanzawai Kishida分别置于15℃,RH80%;20℃,RH75%;25℃,RH70%;30℃,RH65%;35℃,RH60%的恒温恒湿箱内单个饲养,观察其个体发育、孵化率、存活率和产卵量,结果为：35℃,RH60%条件下,雌、雄一代发育历期最短,为(6.23±0.44)山成螨最高日产卵量13.95±3.72)粒;平均日产卵量7.18±1.56)粒; 从成螨开始产卵至死亡50%产卵期最短,为(9.65±1.53)山卵孵化率72.4%;幼螨存活率84.6%。15℃,RH80%条件下,雌、雄一代发育历期最长,为(27.49±2.23)山成螨最高日产卵量(5±1.21)粒;平均日产卵量(2.04±0.55)粒;从成螨开始产卵至死亡50%产卵期最长,为(28.4±4.06)d：卵孵化率85.6%;幼螨存活率97.0%。15℃,RH80%处理成螨寿命为(35±8.85)d,比20℃,75%处理成螨寿命长(13.9±6.4)d。试验结果表明,不同的温湿度对神泽氏叶螨生长发育有一定的影响,35℃发育速率最快,15℃发育速率最慢,20～30℃为最适发育温度。     

High Ambient Carbon-Dioxide does not Affect Respiration by Suppressing the Alternative, Cyanide-resistant Pathway

Total dark respiration (v_t), cytochrome pathway (v_eyt), alternativepathway (v_alt) and residual (v_res) respiration were measuredin Lemna gibba plants, by the use of pathway inhibitors. NaCNwas used to inhibit v_eyt and SHAM (salicylhydroxamic acid) toinhibit v_alt. Residual respiration (v_res) was about 5% of v_t.The effect of high (100 Pa) and low (0 Pa) carbon dioxide partialpressure ([CO₂]) on v_t, v_eyt and v_alt was determined from bothCO₂ efflux and O₂ uptake measurements. The higher [CO₂] suppressedv_t by about 30%. When respiration operated through the cytochromepathway only, in the absence of v_alt, it was suppressed by about12% as measured by the O₂ uptake of submerged Lemna fronds orby about 40% as measured by CO₂ efflux from floating fronds.The higher [CO₂] treatment had only a small effect on respiration,when v_alt alone operated. There was no evidence of a specificsuppression of the v_alt pathway by high [CO₂]. Succinic dehydrogenaseactivity of the mitochondria of roots of Medicago sativum wasreduced by 18%, when the mitochondria were pre-treated with120 as compared to 34 Pa [CO₂]. There was no such effect oncytochrome c oxidase activity of mitochondria under the sameconditions. It is concluded that there is no evidence for the hypothesisthat the high [CO₂] suppression of respiration is a result ofa CO₂ effect on the non-phosphorylating alternative respirationpathway.Copyright 1995, 1999 Academic Press Lemna gibba, Medicago sativum, respiration, cytochrome pathway, alternative pathway, cyanide-insensitive pathway, carbon dioxide, succinic dehydrogenase, cytochrome c oxidase     

Carbon Assimilation at Low Carbon Dioxide Levels: II. THE PROCESSES OF APPARENT ASSIMILATION

The relation of the net uptake or output of carbon dioxide bydetached leaves of Pelargonium zonale or wheat to ambient carbondioxide concentration was investigated at two or three lightintensities. The statistics of fitted curves were used as datain analysis of variance. For Pelargonium the results were consistentwith a hypothesis of a ‘straight balance’ betweena rate of photosynthetic uptake proportional to concentrationand a constant rate of respiratory production. For wheat, however,the curve was steeper near than at lower carbon dioxide levels;this disproved the ‘straight balance’ hypothesisand was consistent with an increase in carbon dioxide fixationor a reduction in output over a limited concentration rangeon either side of . The characteristics of light respiration, possibly carbon dioxidedependent, were investigated further in an experiment on theeffect of oxygen concentrationupon r values for two species(P. zonale and Hydrangea sp.) at two light intensities; theywere also studied by measuring the ‘burst’ of carbondioxide output when leaves were darkened after illuminationat four different light intensities and at two temperatures. was linearly related to oxygen tension up to 610 mm partialpressure of mercury and a fivefold increase in light intensityhad only a very small effect indicating that photoxidation wasnot important. The carbon dioxide burst on darkening showedrelations to temperature and previous light intensity quitedifferent from those of which should be proportional to lightrespiration. These results, therefore, do not support the viewthat the burst represents the persistence of an enhanced lightrespiration.     

CHANGE OF B-TYPE HAEM CONTENT IN RELATION TO PEROXIDASE BIOSYNTHESIS IN INJURED SWEET POTATO ROOTS

The methods of quantitative analysis of b-type haem in plantswere investigated. With an improved method developed was determinedthe haem content in the supernatant, mitochondrial, and microsomalfractions of sweet potato tissue. The activities of peroxidase,catalase, and cytochrome oxidase, as well as the contents ofb-type haem and acid-insoluble nitrogen in the cellular fractionswere determined at different incubation times after cuttingof sweet potato tissue. Peroxidase and catalase increased withtime in each celluler fraction, following a short lag phase.In the mitochondrial fraction, b-type haem, cytochrome oxidase,and acid insoluble nitrogen increased linearly with time. Inthe microsomal and supernatant fraction, b-type haem increasedwith time following a short lag phase. The increase in haemcontent of the supernatant fraction appeared to be associatedwith peroxidase formation. Time course analysis showed that ⁵⁹Fe-incorporation into b-typehaem of the supernatant fraction increased with time and thatincorporation was markedly inhibited by blasticidin S. The incorporationof ⁵⁹Fe into mitochondrial haem did not increase with time andwas not inhibited by blasticidin S. Blasticidin S inhibited⁵⁹Fe-incorporation into microsomal haem. Time course analysisof b-type haem content, ⁵⁹Fe-incorporation into b-type haem,and peroxidase activity suggest that in the injured tissue haemis synthesized from low molecular weight compounds and is incorporatedinto peroxidase as the haem moiety. ¹ This paper constitutes Part 57 of the Phytopathological Chemistryof Sweet Potato with Black Rot. ² Present address: Institute for Plant Virus Research, Chiba.     

Studies on the change of the respiratory system in roots in relation to the growth of plants II. Activity of iron-containing oxidases in roots of cereal crops with the aging of plants

Distribution of iron-containing oxidases in aging nodal rootsof rice and wheat was studied. Activities of cytochrome c oxidase(1.9.3.1 [EC] , cytochrome c : O₂ oxidoreductase), catalase (1.11.1.6 [EC] ,H₂O₂: H₂O₂ oxidoreductase) and peroxidase (1.11.1.7 [EC] , donor:H₂O₂ oxidoreductase) in wheat roots were comparatively higherthan were those in rice roots at corresponding stages. Cytochromec oxidase in roots remained active throughout the lives of therice and wheat crops. In rice roots, catalase seemed to playa distinct role around the panicle formation stage. Decay ofcatalase activity took place earlier than did that of peroxidaseand cytochrome c oxidase activities. In wheat roots similarenzyme activity changes were not observed. Data may suggestthat the high activity of iron containing oxidases at the panicleformation stage (I) may be chiefly due to catalase activityin rice roots. ¹Paper presented at the 14th Annual Meeting of the Society ofthe Science of Soil and Manure, Japan (1968). (Received November 21, 1968; )     

Are mitochondrial lineages,mitochondrial lysis and respiration rate associated with phosphine susceptibility in the maize weevil Sitophilus zeamais?

Phosphine is the most widely used fumigant with ever‐growing problems of phosphine resistance among insect pests of stored products. One such insect is the maize weevil Sitophilus zeamais, a key pest of stored cereals. Despite its importance as a fumigant, the mechanisms of phosphine toxicity and resistance remain unclear, although the mitochondrion is broadly recognised as its site of action. Here we explored the phosphine susceptibility of maize weevil populations and its association with insect respiration rate, and we tested the association of phosphine susceptibility with the mitochondrial lineages from the field populations studied. We also assessed the action of phosphine in the degradation of mitochondria from muscle cells. Survival under phosphine treatment varied among weevil populations and was negatively correlated with the respiration rate and body mass of the insect. Phosphine produced little lysis of mitochondria and the more phosphine‐resistant population exhibited a slightly higher mitochondria fluorescence intensity under confocal imaging. Therefore, reduced respiration rate is correlated with reduced phosphine activity, but its association with high mitochondria fluorescence intensity in muscle cells seems marginal. There was no association between mitochondrial lineages and phosphine susceptibility, which evolved independently, and the mitochondrial gene fragments of cytochrome oxidase I and II were not useful molecular markers of phosphine susceptibility.     

Decreased cytochrome oxidase activity in hepatic mitochondria after chronic ethanol consumption and the possible role of decreased cytochrome aa3 content and changes in phospholipids

In ethanol-fed baboons, hepatic mitochondrial cytochrome oxidase activity and cytochrome aa₃ content were significantly decreased by 58.3 and 50.5%, respectively, compared to their pair-fed controls. However, there was no significant correlation between the two, suggesting that other factors in addition to cytochrome aa₃ may be responsible for the depression in cytochrome oxidase activity. The total phospholipid content of the mitochondrial membranes was significantly decreased (0.24 ± 0.03 μmol of phospholipid phosphorus/mg of protein vs. 0.32 ± 0.04 in controls). This change was accounted for, in part, by the significant decrease in the levels of phosphatidylcholine and cardiolipin. In addition, the fatty acid pattern of the phospholipids was changed. There was a marked increase in the relative amounts of oleic and linoleic acid and a decrease in arachidonic acid. These changes were associated with an increase in the activity of phospholipase A₂. The reactivation rate of phospholipid-depleted cytochrome oxidase by endogenous phospholipids from ethanol-fed baboons was significantly lower than that by phospholipid from pair-fed controls, when measured at an optimal phospholipid to protein ratio. Thus, it appears that alterations in the phospholipid composition of the mitochondrial membranes are responsible, at least in part, for the depression of cytochrome oxidase activity produced by chronic ethanol consumption.     

STUDIES ON COMPONENTS OF RESPIRATORY SYSTEM OF BEGONIA LEAVES

Investigations were made of the properties of diaphorase, cytochromec reductases, cytochrome c oxidase, and other components ofelectron transfer system in various fractions of leaf homogenateof Begonia semperflorens.

1. All the fractions tested showed the existence of cytochromec oxidase, succinic- and reduced diphosphopyridine nucleotide-cytochromec reductases, and diaphorase. Activities of these enzymes werefound to be associated mainly with the particulate fractions.The particulate fractions showed, in particular, a capacityof reducing oxidized cytochrome c with fumarate, malate, -ketoglutarate,ß-hydroxy-butyrate, and citrate.
2. Optimum pH foroxidation of cytochrome c by the particulatefractions was foundto be 5.5, while that for reduction was7.2.
3. The activityof cytochrome c reductase was partially suppressedby malonate.Partial inhibition of cytochrome c oxidase wascaused by azideand cyanide, the inhibitory effects observedbeing strongerwith particulate fractions than with solublefractions.

(Received August 11, 1962; )     

七种抑制剂对两种白蚁谷胱甘肽S-转移酶活性抑制作用的比较

利用分光光度酶动力学方法,确定了白蚁谷胱甘肽S-转移酶（GSTs）的最适反应条件,并进一步研究了7种抑制剂对黑翅土白蚁Odontotermes formosanus (Shiraki)和黑胸散白蚁Reticulitermes chinensis Snyder GSTs活性的体外影响。结果表明：白蚁GSTs测定的最适反应条件为pH 6.5,温度25℃,最适反应时间2 min。黑翅土白蚁GSTs的米氏常数(K_mCDNB和K_mGSH)分别为0.11±0.02 mmol/L和0.81±0.16 mmol/L,最大反应速度(V_maxCDNB和V_maxGSH)分别为425.92±19.67 nmol/(min·mg)和534.86±39.05 nmol/(min·mg)。黑胸散白蚁GSTs的米氏常数(K_mCDNB和K_mGSH)分别为0.12±0.03 mmol/L和1.03±0.31 mmol/L,最大反应速度(V_maxCDNB和V_maxGSH)分别为544.39±37.19 nmol/(min·mg)和715.45±83.68 nmol/(min·mg)。浓度为2×10^-5 mol/L时,槲皮素和辛硫磷对黑胸散白蚁GSTs活性的抑制作用要强于黑翅土白蚁,对黑胸散白蚁GSTs活性的抑制作用分别为62.28％和44.89％,对黑翅土白蚁GSTs活性的抑制作用分别为54.96％和28.36％。高效氯氰菊酯、甲氰菊酯、啶虫脒和单宁酸对黑翅土白蚁GSTs活性的抑制作用要强于黑胸散白蚁,对黑翅土白蚁GSTs活性的抑制作用分别为39.43％,72.07％,52.24％和82.19％;对黑胸散白蚁GSTs活性的抑制作用分别为14.96％,40.23％,39.96％和57.80％。阿维菌素对黑翅土白蚁和黑胸散白蚁GSTs活性的抑制作用没有显著差异,对黑翅土白蚁和黑胸散白蚁GSTs活性的抑制作用分别为76.21％和76.88％。这表明两种白蚁对药剂的敏感性完全不同。实验结果还表明,在3.2×10^-8～2×10^-5 mol/L内,上述植物次生物质和杀虫剂对两种白蚁GSTs活性的抑制率存在明显的剂量-效应关系。