Elevated CO2 alters anatomy,physiology, growth,and reproduction of red mangrove (Rhizophora mangle L.)

Mangroves, woody halophytes restricted to protected tropical coasts, form some of the most productive ecosystems in the world, but their capacity to act as a carbon source or sink under climate change is unknown. Their ability to adjust growth or to function as potential carbon sinks under conditions of rising atmospheric CO₂ during global change may affect global carbon cycling, but as yet has not been investigated experimentally. Halophyte responses to CO₂ doubling may be constrained by the need to use carbon conservatively under water-limited conditions, but data are lacking to issue general predictions. We describe the growth, architecture, biomass allocation, anatomy, and photosynthetic physiology of the predominant neotropical mangrove tree, Rhizophora mangle L., grown solitarily in ambient (350 ll^–1) and double-ambient (700 ll^–1) CO₂ concentrations for over 1 year. Mangrove seedlings exhibited significantly increased biomass, total stem length, branching activity, and total leaf area in elevated CO₂. Enhanced total plant biomass under high CO₂ was associated with higher root:shoot ratios, relative growth rates, and net assimilation rates, but few allometric shifts were attributable to CO₂ treatment independent of plant size. Maximal photosynthetic rates were enhanced among high-CO₂ plants while stomatal conductances were lower, but the magnitude of the treatment difference declined over time, and high-CO₂ seedlings showed a lower P_max at 700 ll^–1 CO₂ than low-CO₂ plants transferred to 700 ll^–1 CO₂: possible evidence of downregulation. The relative thicknesses of leaf cell layers were not affected by treatment. Stomatal density decreased as epidermal cells enlarged in elevated CO₂. Foliar chlorophyll, nitrogen, and sodium concentrations were lower in high CO₂. Mangroves grown in high CO₂ were reproductive after only 1 year of growth (fully 2 years before they typically reproduce in the field), produced aerial roots, and showed extensive lignification of the main stem; hence, elevated CO₂ appeared to accelerate maturation as well as growth. Data from this long-term study suggest that certain mangrove growth characters will change flexibly as atmospheric CO₂ increases, and accord with responses previously shown in Rhizophora apiculata. Such results must be integrated with data from sea-level rise studies to yield predictions of mangrove performance under changing climate.     

大豆结瘤突变体成分的初步分析及其对硝酸还原酶活性和结瘤的影响

超结瘤大豆（Ｇｌｙｃｉｎｅ ｍ ａｘ （Ｌ．） Ｍｅｒｒ．） ｎｔｓ ３８２ 和不结瘤大豆Ｎｏｄ ４９ 的叶和根组织水提取物经Ｓｅｐｈａｄｅｘ Ｇ２５ 过滤、洗脱,再根据洗脱物对硝酸还原酶（ＮＲ）活性的影响可划分为４ 个组分（ｆｒａｃｔｉｏｎ）样品,即ｎｔｓ ３８２（Ｎｏｄ ４９） Ｆ１、ｎｔｓ ３８２（Ｎｏｄ ４９） Ｆ２、ｎｔｓ ３８２（Ｎｏｄ ４９） Ｆ３ 和ｎｔｓ ３８２（Ｎｏｄ ４９） Ｆ４。其中, ｎｔｓ３８２ Ｆ２ 和Ｆ４ 抑制ＮＲ 活性作用在接种ＵＳＤＡ１１０ 后明显下降, 但接种的ｎｔｓ ３８２ Ｆ２ 却能提高大豆Ｂｒａｇｇ 的结瘤数达一倍, 而接种的ｎｔｓ ３８２ Ｆ３ 和Ｆ４ 的作用不明显。ＮＲ 活性抑制因子不是刺激结瘤的因子, 刺激结瘤的因子主要分布在接种的ｎｔｓ３８２ Ｆ２ 部分中。与这一现象相反, Ｎｏｄ ４９ Ｆ２ 和Ｆ４ 抑制ＮＲ活性的作用在接种后更强, 且也抑制大豆ｎｔｓ ３８２ 的结瘤, 其中Ｎｏｄ ４９ Ｆ４ 抑制结瘤的作用基本不能逆转。抑制结瘤因子主要分布在接过种的Ｎｏｄ ４９ Ｆ４ 部分中     

紫竹梅雄蕊毛细胞发育过程中胞间连丝超微结构的变化

紫竹梅（Ｓｅｔｃｒｅａｓｅａ ｐｕｒｐｕｒｅａ）雄蕊毛细胞间的胞间连丝随着细胞的生长、发育、衰老而呈现动态变化的过程．花蕾和开放花的雄蕊毛细胞间的胞间连丝,具备胞间连丝的一般结构,直径约５０ ｎｍ ．衰老花雄蕊毛细胞间的胞间连丝拓宽,内部结构逐步降解、撤离,呈开放式通道,直径约１００ ｎｍ ． 在胞间连丝的动态开放过程中,细胞内的细胞器也发生相应变化． 对胞间连丝形成开放性通道及其机理进行了讨论     

从玉米胚中大量制备植物钙调素

从每公斤萌发２４ｈ的玉米胚丙酮粉中可提纯得６３ｍｇ的钙调素（ＣａＭ）,这是目前从每公斤植物材料中所提纯得ＣａＭ的最高记录。对其理化性质的研究表明,玉米胚ＣａＭ 有较高的生物学活性,能较好地激活磷酸二酯酶,其紫色吸收光谱,ＳＤＳ－ＰＡＧＥ电泳行为及氨基酸组成与其它的植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ的适宜材料。     

The Role in Ozone Phytotoxicity of the Evolution of Ethylene upon Induction of 1-Aminocydopropane-1-carboxylic Acid Synthase by Ozone Fumigation in Tomato Plants

The rate of evolution of ethylene by tomato plants was rapidlyincreased by O₃ fumigation. The time course of the increasein 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activitywas the same as that in the rate of evolution of ethylene, suggestingthat ACC synthase activity might be a rate-limiting step inthe evolution of ethylene that is caused by O₃ fumigation. Therate of the O₃-induced evolution of ethylene was increased bythe application of ACC to tomato plants, suggesting the involvementof ACC oxidase in the O₃-induced evolution of ethylene. Treatmentof plants with tiron inhibited the evolution of ethane, butnot of ethylene. These results indicated that evolution of ethylenein O₃-treated tomato plants might result from enzymatic reactionscatalyzed by both ACC synthase and ACC oxidase, but not fromstimulation by O₃ of the peroxidation of lipids mediated byfree radicals. Pretreatment of leaves with aminoethoxyvinylglycine (AVG), aninhibitor of ACC synthase, significantly inhibited the evolutionof ethylene that was induced by O₃ and concomitantly reducedthe extent of O₃-induced visible damage to leaves. Treatmentwith 2,5-norbonadiene, an inhibitor of the action of ethylene,strongly reduced the extent of visible damage caused by O₃,even though it did not suppress the evloution of ethylene. Theseresults indicate that ethylene acts on certain metabolic processesto cause visible damage. (Received September 7, 1995; Accepted December 18, 1995)     

Evaluation of hydroxyl radical-scavenging property of garlic

While antibiotics are broadly used in dental and medical therapy, little attention has been directed towards the potential toxic side effects of antibiotics on tissue regeneration. Here we examined the effect of a quinolone antibiotic, pefloxacin (Rhone Poulenc) on rat parotid gland responses to chronic isoproterenol treatment. Groups of rats received injections of isoproterenol to induce glandular growth, saline (controls), pefloxacin, or isoproterenol and pefloxacin in combination. Parotid gland weight decreased significantly after pefloxacin treatment for 7 days as well as inhibiting glandular enlargement provoked by isoproterenol. The same trend was observed for the rates of DNA synthesis, with the incorporation of [³H]-thymidine in isoproterenol/pefloxacin-treated rats reduced to 49% of isoproterenol treatment alone levels. Saline-treated animals were 42% of the rate of [³H]-thymidine incorporation into DNA observed in isoproterenol treated rats. While isoproterenol treatment increased steady-state mRNA levels for fos, jun, myc, src, c-erbB-2, ras and topo II, inclusion of pefloxacin with the isoproterenol regimen blocked these increases. Pefloxacin treatment by itself did not alter proto-oncogene mRNA levels in the parotid gland. Glandular amylase activity was decreased in the pefloxacin treated group, while the combination of isoproterenol with pefloxacin did not decrease glandular amylase levels to the extent of that observed with -agonist treatment alone. In acute experiments, pefloxacin significantly decreased the volume of saliva secreted by the parotid gland. These results suggest that quinolone-based antibiotics disturb the secretory function of the parotid gland and can inhibit cell proliferation and regeneration. (Mol Cell Biochem 165: 55–63, 1996)     

部分酶解酵母高效电击转化研究

以酵母质粒YCp50为外源DNA,电击转化部分酶解酵母宿主菌AB1380,转化效率稳定在10~6转化子/μg质粒DNA左右,比不酶解酵母或酵母原生质球作受体的电击转化效率高一个数量级以上,也比PEG介导的酵母原生质球转化高3～5倍,而且适合于大片段DNA如水稻YAC分子的转化。达最佳转化时的有关技术参数为:新接菌种通气培养至细胞密度1×10~8～1.5×10~8个/ml;转化时细胞密度控制在1×10~9～1.5×10~9个/ml;每毫升酶解缓冲液加15u溶菌酶(lyticase),30℃下处理酵母5min进行部分酶解;电击时,电场设置在6.25kV/cm、电容25μF,电击后直接铺板。     

猪精子凝集素的纯化,性质及其作用

用胎球蛋白－Ｓｅｐｈａｒｏｓｅ亲和层析和凝胶过滤层析从精子和精浆中分离纯化了猪精子凝集素（简称ＢＳＬ）。ＢＳＬ的血凝活性只被若干糖蛋白和聚糖所抑制。ＢＳＬ的分子量为５６ｋｄ,由分子量分别为１３．６ｋｄ（β）和１６．０ｋｄ（α）的两个不同的亚基以α１β３所组成。ＢＳＬ为糖蛋白,含中性糖３．２％,不含唾液酸。用ＥＬＩＳＡ法测定猪精子中ＢＳＬ的含量及分布,表明７０％嵌入在精子膜中,２５％结合在精子表面,     

细胞寒害的热力学熵理论(Ⅱ)──超熵产生作为寒害稳定性判据的理论研究

本文从物质和能量交换的角度,运用非平衡态热力学超熵产生理论,分析了寒害定态的稳定性,并建立了超熵产生判据．理论分析所得的结论与实验结果基本相符．     

用人工合成的丁型肝炎病毒抗原多肽检测丁肝病毒IgM抗体及其初步应用

用人工合成的丁型肝炎病毒抗原（ＨＤＶ－Ａｇ）肽建立了检测抗ＨＤＶ－ＩｇＭ抗体的ＥＬＩＳＡ方法,本法操作简便、快速,重复性好,特异性强,与抗ＨＡＶ－ＩｇＭ、抗Ｈｋ－ＩｇＭ、抗ＨＢｓ－ＩｇＭ、抗ＨＣＶ－ＩｇＩ、抗ＣＭＶ－ＩｇＭ、抗ＲＶ－ＩｇＭ、类风湿因子（ＲＦ）及抗核抗体（ＡＮＡ）阳性血清均不起反应,且可被２－巯基乙醇阻断而不起反应。经初步临床应用,３１例正常人血清抗ＨＤＶ－ＩｇＭ全部阴性,２８例慢活肝患者检出率为３２．１％（９／２８）,１７例慢迁肝患者血清阳性率为１１．８％（２／１７）１８例肝癌和肝硬化病人血清阳性率为２２．２％（４／１８）这三组病人与正常对照者相比较均有显著性差异（Ｐ＜０．００１）。此外,抗ＨＤＶ－ＩｇＭ阳性血清的ＡＬＴ值均明显高于正常参考范围,提示在ＨＤＶ感染过程中,患者肝细胞进一步受损。实验结果证明,抗ＨＤＶ－ＩｇＭ是诊断ＨＤＶ感染的重要指标,对ＨＤＶ感染早期诊断具有重要价值。