接种菌根菌短枝木麻黄对低温胁迫的响应特征

通过对接种不同菌根菌短枝木麻黄幼枝进行系列低温胁迫处理,分析抗寒性相关生理指标与接种菌根菌短枝木麻黄抗寒性关系,探讨短枝木麻黄接种菌根菌对低温胁迫的响应特征,为科学评价和改良短枝木麻黄的抗寒能力提供依据。结果表明:(1)接种菌根菌有助于短枝木麻黄形成菌根,可显著促进其苗期生长。(2)随着胁迫温度的降低,接种菌根菌短枝木麻黄嫩枝SOD、POD、CAT活性均呈先上升后下降的趋势,MDA含量逐渐增加,且细胞膜透性均升高。(3)与相同温度处理下未接种对照相比,7个接种处理短枝木麻黄的嫩枝SOD、POD、CAT活性显著提高,并在0～4℃达到最高值,其MDA含量和细胞膜透性显著降低,而且各菌株处理的升降幅度存在显著差异。研究发现,在一定低温胁迫下,接种菌根菌可以显著提高短枝木麻黄嫩枝主要保护酶活性,有效降低其细胞膜透性和MDA含量,从而提高自身抗寒能力;接种内生菌根菌苏格兰球囊霉和外生菌根菌多根硬皮马勃对短枝木麻黄耐寒性的促进效果最佳。     

Ca2+对铬胁迫下木麻黄种子萌发的生态效应

研究不同浓度Ca2 + 对铬胁迫下木麻黄种子萌发的影响。结果表明 ,在 10mgCr3 + ·L-1或 10 0mgCr3 + ·L-1胁迫下 ,木麻黄种子萌发及幼苗生长发育受到抑制 ,较高浓度的Cr3 +显示更大的毒性效应 ;在加入适量Ca2 + 处理后 ,植物虽仍处在铬胁迫下 ,但脯氨酸、O-2 、MDA含量以及POD、CAT活性有所下降 ,SOD活性上升 ,缓解了铬对种子萌发的抑制和幼苗生长发育的影响。Ca2 + 表现出对铬胁迫下木麻黄种子萌发和幼苗膜保护酶活性有积极的调控作用 ,且可调节脯氨酸应激反应的灵敏程度 ,降低活性氧的产生速率和膜脂过氧化程度 ,但Ca2 + 处理需要适当的浓度 ,浓度过高会产生负效应。Ca2 + 调控的最适浓度为 0 0 1～ 1mmol·L-1。     

Functional diversity of soil microorganisms in Casuarina equisetifolia woodlands of different stand ages in Hainan Island

为研究不同林龄木麻黄(Casuarina equisetifolia)林地土壤微生物功能多样性的动态变化, 通过Biolog系统对海口市桂林洋开发区滨海不同林龄(幼龄林(林龄5-8年)、中龄林(林龄15-20年)和成熟林(林龄30年及以上))的木麻黄林地土壤微生物的功能多样性进行了分析。结果表明: (1)对照裸地和成熟林林地土壤微生物对所使用的Biolog-ECO微孔板中的31种碳源的利用率和对这31种碳源的各分类碳源的利用率高于中龄林与幼龄林林地; (2) Shannon-Wiener指数(H′), McIntosh、Simpson多样性指数随着林龄增大而增大, 不同林龄林地间的H′差异显著, 幼龄林和中龄林的McIntosh、Simpson多样性指数无显著差异; (3)主成分分析结果表明, 在主成分分离中起分异作用的主要碳源为单糖和氨基酸。林地土壤微生物群落多样性随着林龄增加而增高, 这可能是林分凋落物、植物根系分泌的次生代谢物、土壤养分、林地土壤特异性微生物等共同作用的结果。     

细枝木麻黄气生瘤的人工形成

细枝木麻黄气生瘤的人工形成邹铧,张忠泽,张成刚,丁鉴,王育英,付莉（中国科学院沈阳应用生态研究所,沈阳１１００１５）ＡｒｔｉｆｉｃｉａｌｆｏｒｍａｔｉｏｎｏｆａｅｒｉａｌｎｏｄｕｌｅｓｏｎＣａｓｕａｒｉｎａｃｕｎｎｉｎｇｈａｍｉａｎａ￥ＺｏｕＨｕａ;...     

A simple and efficient method for clonal propagation of Casuarina sumatrana (de Vriese) L. Johnson

A new and efficient method for clonal propagation of Casuarina sumatrana by rooting stem cuttings is described. High percentage (about 60–70%) of rooting was achieved with mature softwood stem cuttings. A quick-dip of 5 s in NAA (1–10mM) solution followed by sand culture under high humidity were required for a high rate of survival and rooting of stem cuttings. A simple, closed chamber propagation system, using fluorocarbon polymer (tetrafluoroethyleneperfluoroalkyl vinyl ether) film (Neoflon PFA film), was successfully developed for the rooting of stem cuttings without mist. Rooted cuttings inoculated with Frankia were easily transplanted and established in field conditions with very low (about 3%) mortality. The significance of these findings for mass clonal propagation of C. sumatrana is discussed.Abbreviations IBA indole-3-butyric acid - NAA -naphthaleneacetic acid     

Iron deficiency induces cluster (proteoid) root formation in Casuarina glauca

The effect of iron deficiency, phosphorus, NaHCO₃, chelator supply and nitrogen source on the formation of cluster (proteoid) roots was investigated in Casuarina glauca growing in water culture. The addition of iron-binding chelators (e.g. EDDHA, DTPA, EDTA) or increase in nutrient solution pH with NaHCO₃ resulted in the formation of cluster roots when plants were grown in solution lacking iron. Phosphorus supply even at a concentration of 500 µM did not inhibit cluster root formation if EDDHA was added to the iron-deficient medium. Cluster root formation was influenced significantly by nitrogen source and occurred only in nitrate-fed plants.C. glauca seemed to be very sensitive to iron deficiency as shown by plant chlorosis when grown on alkaline soil. The symptoms of chlorosis decreased as the chlorophyll content in shoots and the number of cluster roots increased, suggesting that the alleviation of iron deficiency in plant tissues was correlated with cluster root formation. It appears that iron deficiency is more important than phosphorus deficiency in inducing the formation of cluster roots in C. glauca.     

Cloning of a full-length symbiotic hemoglobin cDNA and in situ localization of the corresponding mRNA in Casuarina glauca root nodule

We have characterized a full-length cDNA ( hb -Cg1F) that represents symbiotic mRNA hemoglobin ( hb ) from Casuarina glauca root nodules. In situ hybridization was used to examine the correlation between hb -Cg1F mRNA and the state of the Frankia infection process. The efficiency of in situ hybridization using DIG-labeled vs [³⁵S]-labeled probes was compared. The expression of hb -Cg1F gene is induced in young infected host cells prior to the detection of Frankia nif H mRNA. Since Frankia does not form vesicles in C. glauca nodules, it is proposed that Hb is necessary to reduce the O₂ concentration in the cytoplasm of the host cells before the nif genes are expressed.     

The capacity of Jamaican mine spoils, agricultural and forest soils to nodulate Myrica cerifera, Leucaena leucocephala and Casuarina cunninghamiana

Soils from seven sites on the island of Jamaica were assayed for the symbiotic diazotrophs Frankia and Rhizobium using serial dilutions. Most probable number and least squares regression methods were used to estimate each soil's capacity to nodulate native Myrica cerifera, exotic Leucaena leucocephala and exotic Casuarina cunninghamiana. The sample sites included a montane forest, a slash-and-burn agricultural site, reclaimed bauxite mining areas, abandoned sugar cane fields, and a garden plot. None of the host plants used in the bioassay were present on the sites sampled except for scattered L. leucocephala on one site. Frankia capable of nodulating M. cerifera, which is native to Jamaican highlands, occurred at all sites sampled. No C. cunninghamiana-infective Frankia was detected in soils sampled. Only soils from one site on the tropical coastal plain harbored rhizobia able to nodulate L. leucocephala (37 nodulation units cm^?3 of soil). A subset of nodulated M. cerifera and L. leucocephala reduced acetylene to ethylene indicating nitrogenase activity. The slash-and-burn agricultural site, which was situated at an elevation of 200 m and possessed both high natural fertility and high soil moisture-supplying capacity, had significantly greater Myrica infectious capacity (1 000 nodulation units cm^?3 of soil) than the other sites (7?207 nodulation units cm^?3 of soil). A planned, paired comparison revealed that a recently cultivated sugar cane field and a recently reclaimed bauxite mining site together had significantly less Myrica-infective Frankia (4 nodulation units cm^?3 of soil) than a corresponding pair of sites consisting of a sugar cane field abandoned for 25 years and a bauxite mining site reclaimed 20 years before sampling (118 nodulation units cm^?3 of soil). Results indicate that Myrica-infective Frankia is widespread in Jamaica, that the number of Myrica-infective Frankia units vary from site to site in accordance with soil type and soil history, that Jamaican sites sampled lack soil Frankia populations capable of nodulating a casuarina host, that rhizobial symbionts capable of nodulating L. leucocephala may be geographically restricted to lowlands in Jamaica, and that the occurrence of Frankia in these soils is independent of host plant presence.     

四种单宁植物形成层的活动周期和次生韧皮部的季节变化

余甘子Ｐｈｙｌｌａｎｔｈｕｓｅｍｂｌｉｃａ．Ｌ杨梅Ｍｙｒｉｃａｒｕｂｒａ（Ｌｏｕｒ）．Ｓｉｅｂ．ｅｔＺｕｃｃ,黑荆树ＡｃａｃｉａｍｅａｒｓｉｉＤｅＷｉｌｄｅ形成层的活动有明显的季节性,形成层活动期分别为５～１１月,３～１２月,２～１０月,其他时间休眠,细枝木麻黄ＣｗａｓｕａｒｉｎａｃｕｎｎｉｎｇｈａｉａｎａＭｉｑ的形成层周年都在活动１,２月的材料中也见到成膜林,４种树木在冬季都保留相当数量的具功能