松嫩平原不同生境芦苇种群分株的生物量分配与生长分析

在松嫩平原8月中旬,4个旱地生境芦苇种群分株的生长和生产力以季节性临时积水的低洼地为最高,以碱斑地为最低,两个生境之间分株高度相差2.8倍,分株生物量相差4.4倍,其它2个生境沙地和草甸混生 少也达到了显著或极显著水平,不同生境芦苇种群分株生物量分配的差异,蕴涵着重要的生长调节和物质分配策略。在分株株较小而又有充分生长空间的沙地生境和三斑生境,以及具有种间竞争的草句生境,分株将50％以上的物质分配给叶的建造上,以保证充分的物质生产;在环境条件相对较好的低洼地生境,分株将近40％的物质分配给茎的伸长生长,以提高个体对空间和光资源的竞争力。4个生境芦苇种群在分株增高与增重,以及茎、叶与分株的相对增重均具有相同的幂函数异速生长规律。     

旱区盐生植物根际促生菌的分离鉴定及其干旱、盐胁迫下促生特性

【目的】从在干旱、高盐碱生境下生长的盐生杂类草根际土壤中分离具有耐盐和促生性能的根际微生物,并研究其促生特性,为改良旱区土壤盐碱化提供优质菌种资源和理论基础。【方法】通过选择培养基筛选具有耐盐、解磷和解钾能力的菌株,再检测菌株产生长激素(indole-3-acetic acid,IAA)、产1-氨基环丙烷-1-羧酸(1-aminocyclopropane-1-carboxylate,ACC)脱氨酶、产铁载体以及产胞外多糖的能力,选择性状优良者通过拮抗实验组建复合菌剂。并采用菌液侵染萝卜和玉米种子验证菌株对在盐胁迫下种子发芽率和植株在干旱与盐双重胁迫下生长的影响。最后通过16S rRNA基因测序进行分子生物学鉴定。【结果】得到3株具有良好耐盐促生能力的根际微生物yl923、hs032和hy127,菌株yl923兼具解磷(46.29 mg/L)、解钾(58.07 mg/L)、产IAA(29.23 mg/L)、产ACC脱氨酶(13.83 U/mg)和产铁载体(SU=0.43)能力,菌株hs032具有最强产IAA(61.18mg/L)和产铁载体(SU=0.23)能力,菌株hy127具有最强产ACC脱氨酶(15.29U/mg)能力。经16SrRNA基因序列分析后分别将yl923和hs032鉴定为枯草芽孢杆菌(Bacillus subtilis),hy127鉴定为巨大普里斯特氏菌(Priestia megaterium)。3株菌互不拮抗可组建复合菌剂,2%混合菌液可提高种子在盐胁迫下种子发芽率(77%),对干旱和盐胁迫下玉米的根长、株高、干重和叶绿素也都有显著的提高(P<0.05),并且可以显著地降低玉米体内丙二醛(malondialdehyde,MDA)含量(60%)。【结论】菌株yl923、hs032和hy127具有优秀的耐盐促生性能,组合成的混合菌剂能在干旱和盐胁迫下促进植物的生长,具有改良旱区盐渍化土壤的潜力。     

Combat of iron-deprivation through a plant growth promoting fluorescent Pseudomonas strain GRP3A in mung bean (Vigna radiata L. Wilzeck)

Microorganisms and plants sustain themselves under iron-deprived conditions by releasing siderophores. Among others, fluorescent pseudomonads are known to exert extensive biocontrol action against soil and root borne phytopathogens through release of antimicrobials and siderophores. In this study, production and regulation of siderophores by fluorescent Pseudomonas strain GRP3A was studied. Among various media tested, standard succinate medium (SSM) promoted maximum siderophore production of 56.59 mg l(-1). There were low levels of siderophore in complex media like King's B medium, trypticase soya medium and nutrient medium (41.27, 29.86 and 27.63 mg l(-1)), respectively. In defferrated SSM, siderophore level was quantified to be 68.74 mg l(-1). Supplementation with iron (FeCl3) resulted in decreased siderophore levels depending on concentration. Siderophore production was promoted by Zn2+ (78.94 mg l(-1)), Cu2+ (68.80 mg l(-1)) whereas Co2+ (57.33 mg l(-1)) and Fe3+ reduced siderophore production (37.44 mg l(-1) as compared to control (55.97 mg l(-1)). Strain GRP3A showed plant growth promotion under iron limited conditions.     

芦苇（Phragmites communis）光合作用与蒸腾作用的日进程

测定了野生芦苇（Ｐｈｒａｇｍｉｔｅｓｃｏｍｍｕｎｉｓ）光合作用、蒸腾作用及相关指标的日变化。叶片的净光合作用率在１０∶００～１５∶００间保持一个高的稳定阶段,平均为７３～９９μｍｏｌＣＯ２·ｍ－２·ｓ－１,光饱和状态下的最大值为１２７μｍｏｌＣＯ２·ｍ－２·ｓ－１,处于挺水植物的低限。蒸腾作用强度的峰值达４８ｍｍｏｌＨ２Ｏ·ｍ－２·ｓ－１。光合作用和蒸腾作用的日进程均未发生“午休”现象;相反,二者都是在正午前后强度最大。光合光量子流密度与净光合作用率、蒸腾强度、叶面传导率均存在不同程度的正相关。芦苇的光合作用强度和水分利用效率相对较低,但年生产量却较高,这是因为芦苇具有密实的叶子、有利的叶片配置结构和高的蒸腾作用强度。     

Culturable bacteria from Zn‐ and Cd‐accumulating Salix caprea with differential effects on plant growth and heavy metal availability

Aims: To characterize bacteria associated with Zn/Cd‐accumulating Salix caprea regarding their potential to support heavy metal phytoextraction. Methods and Results: Three different media allowed the isolation of 44 rhizosphere strains and 44 endophytes, resistant to Zn/Cd and mostly affiliated with Proteobacteria, Actinobacteria and Bacteroidetes/Chlorobi. 1‐Aminocyclopropane‐1‐carboxylic acid deaminase (ACCD), indole acetic acid and siderophore production were detected in 41, 23 and 50% of the rhizosphere isolates and in 9, 55 and 2% of the endophytes, respectively. Fifteen rhizosphere bacteria and five endophytes were further tested for the production of metal‐mobilizing metabolites by extracting contaminated soil with filtrates from liquid cultures. Four Actinobacteria mobilized Zn and/or Cd. The other strains immobilized Cd or both metals. An ACCD‐ and siderophore‐producing, Zn/Cd‐immobilizing rhizosphere isolate (Burkholderia sp.) and a Zn/Cd‐mobilizing Actinobacterium endophyte were inoculated onto S. caprea. The rhizosphere isolate reduced metal uptake in roots, whereas the endophyte enhanced metal accumulation in leaves. Plant growth was not promoted. Conclusions: Metal mobilization experiments predicted bacterial effects on S. caprea more reliably than standard tests for plant growth‐promoting activities. Significance and Impact of the Study: Bacteria, particularly Actinobacteria, associated with heavy metal‐accumulating Salix have the potential to increase metal uptake, which can be predicted by mobilization experiments and may be applicable in phytoremediation.     

Suppression of Rhizoctonia solani diseases of sugar beet by antagonistic and plant growth-promoting yeasts

AIMS: Isolates of Candida valida, Rhodotorula glutinis and Trichosporon asahii from the rhizosphere of sugar beet in Egypt were examined for their ability to colonize roots, to promote plant growth and to protect sugar beet from Rhizoctonia solani AG-2-2 diseases, under glasshouse conditions. METHODS AND RESULTS: Root colonization abilities of the three yeast species were tested using the root colonization plate assay and the sand-tube method. In the root colonization plate assay, C. valida and T. asahii colonized 95% of roots after 6 days, whilst Rhod. glutinis colonized 90% of roots after 8 days. Root-colonization abilities of the three yeast species tested by the sand-tube method showed that roots and soils attached to roots of sugar beet seedlings were colonized to different degrees. Population densities showed that the three yeast species were found at all depths of the rhizosphere soil adhering to taproots up to 10 cm, but population densities were significantly (P < 0.05) greater in the first 4 cm of the root system compared with other root depths. The three yeast species, applied individually or in combination, significantly (P < 0.05) promoted plant growth and reduced damping off, crown and root rots of sugar beet in glasshouse trials. The combination of the three yeasts (which were not inhibitory to each other) resulted in significantly (P < 0.05) better biocontrol of diseases and plant growth promotion than plants exposed to individual species. CONCLUSIONS: Isolates of C. valida, Rhod. glutinis and T. asahii were capable of colonizing sugar beet roots, promoting growth of sugar beet and protecting the seedlings and mature plants from R. solani diseases. This is the first successful attempt to use yeasts as biocontrol agents against R. solani which causes root diseases. SIGNIFICANCE AND IMPACT OF THE STUDY: Yeasts were shown to provide significant protection to sugar beet roots against R. solani, a serious soil-borne root pathogen. Yeasts also have the potential to be used as biological fertilizers.     

造纸废水对芦苇实生苗生长特性及根系活力的影响

以室内水培的芦苇实生苗为材料,研究6种不同化学需氧量(CODcr)浓度造纸废水处理对芦苇生长指标和根系活力的影响,为利用造纸废水修复自然环境中芦苇实生苗种群提供理论依据。结果表明:(1)不同浓度造纸废水对芦苇各器官鲜(干)重有显著的促进作用,并以中等浓度(300mg.L-1)最为明显;随着造纸废水浓度的增加,废水对芦苇各器官鲜(干)重的促进作用有所减弱,这种减弱幅度在芦苇不同器官上存在差异。(2)高浓度造纸废水导致芦苇根生物量比、根状茎生物量比降低,但影响二者降低的废水浓度存在差异;低浓度造纸废水导致芦苇茎生物量比下降,并使叶生物量比增加。(3)随着造纸废水浓度的增加,芦苇的根系活力呈先上升后下降的趋势,并以CODcr浓度为300mg.L-1时的芦苇的根系活力最强,CODcr浓度为900mg.L-1时最弱。可见,低浓度造纸废水促进了芦苇的生长和根系活力,高浓度废水促进作用减弱甚至会抑制根系活力,并以CODcr浓度为300mg.L-1时芦苇实生苗生长最好。     

一株耐盐碱细菌肺炎克雷伯氏菌(Klebsiella pneumoniae) NP36的分离鉴定及全基因组分析

【背景】 近年来,大庆地区土壤盐碱化问题日渐严峻,严重威胁作物生长。盐碱土中存在的耐盐碱促生菌可缓解盐碱环境对作物的胁迫。【目的】 从水稻根际土壤中获取耐苏打盐碱的促生菌资源以提高水稻对盐碱环境的抗性,促进水稻生长。【方法】 利用改良后的培养基筛选获得耐盐碱细菌,利用功能培养基测定其促生能力;通过16S rRNA基因序列分析鉴定菌株,并结合全基因组分析菌株基因组信息。【结果】 筛选得到菌株NP36,鉴定结果为肺炎克雷伯氏菌(Klebsiella pneumoniae),其在pH 3.0−11.0及苏打盐80−200 mmol/L的LB培养基中均可生长。菌株NP36具有产吲哚乙酸(indole-3-acetic acid, IAA)能力,可达(87.27±0.11) mg/L;具有溶无机磷能力,最大有效磷增量为(93.22±1.94) mg/L。相较于无菌水浸种处理,1.0×10⁷ CFU/mL菌悬液浸种显著促进水稻胚根和侧根的生长。通过全基因组测序分析发现,菌株NP36具有合成有机酸和运输磷酸盐的基因。此外,在菌株NP36基因组中还发现氨基酸合成和K⁺转运的相关基因,分析菌株NP36通过细胞氧化还原反应和维持渗透压来抵抗盐碱胁迫。【结论】 本研究验证了菌株NP36对水稻的促生能力,并在基因组水平分析菌株NP36解磷和耐盐碱的机制,为开发耐盐碱促生菌生物肥料提供了理论依据和菌种资源。     

Carrier-based Preparations of Plant Growth-promoting Bacterial Inoculants Suitable for use in Cooler Regions

Summary Carrier-based preparations of two plant growth-promoting rhizobacteria (PGPR) viz. Bacillus subtilis and Pseudomonas corrugata, developed in five formulations were evaluated for their growth promotion, rhizosphere colonization, and viability under storage. The effect of these formulations as fresh preparations, and after 6 months of storage at 4 °C and room temperature, was also determined. The bacterial inoculants in all the formulations were found to enhance the growth parameters of the test plant species; best results were obtained in case of alginate-based formulations. Maximum numbers of inoculated bacteria were recovered from the rhizosphere of alginate-based formulation-treated plants after 6 weeks of growth. Viability of bacterial inoculants was maximal in alginate beads, and alginate beads supplemented with skim milk formulations, after 180 days of storage at 4 °C.     

芦苇细胞培养中的染色体稳定性及诱变效应

培养一年后的芦苇愈伤组织中,仍以80%的八倍体细胞占绝对优势。染色体数目变异范围在105—26之间。而 EMS 处理的愈伤组织与末经处理的愈伤组织相比较,明显地具有比较高的染色体数目变异和倍性变异。     

Treatment of potato tubers with a growth promotingPseudomonas sp.: Plant growth responses and bacterium distribution in the rhizosphere

Rifampicin-nalidixic acid resistant mutants of a plant growth promotingPseudomonas sp., strain PsJN, were evaluated for their ability to stimulate in vitro growth of potato. Two mutant strains, MFE (a consistent growth promoter), and IIM15 (an inconsistent growth promoter), were selected for root colonization study. Root colonization of potato plants was consistently greater with MFE than with IIM15. The population density of indigenous bacteria on the root surface of potato plants inoculated with strain MFE was significantly lower as compared to non-bacterized controls and to the plants bacterized with strain IIM15. Soil sterilization did not affect plant growth in any of the treatments. Bacterization of seed tubers with strain MFE stimulated plant emergence and root development in the field, during the first two weeks after planting. Bacterized plants also formed stolons and tubers earlier and had increased yields of commercial size tubers (55 mm) as compared to non-bacterized controls. Root colonization by strain MFE was positively correlated with plant growth stimulation.     

芒萁根际复合微生物菌剂对绿豆幼苗生长及根际微生物群落的影响

【背景】在农业可持续发展背景下,复合微生物菌剂因其多种微生物间的互补作用成为促进植物生长的有效策略。【目的】研究芒萁(Dicranopteris dichotoma)根际复合微生物菌剂对绿豆幼苗的促生效果,以及对根际微生物群落结构变化的影响。【方法】以前期分离自芒萁根际土壤的4株根际促生菌为供试菌株,组合配制成2种复合微生物菌剂BFF和BBF接种至绿豆幼苗根际,测定绿豆幼苗培养36d后的生理指标及土壤理化性质,并利用16SrRNA基因和ITS扩增子测序技术分析根际微生物结构组成和多样性。【结果】BFF组显著提高了绿豆幼苗的株高、地上部分鲜重和干重以及地下部分干重,分别比对照组提高了29.38%、81.47%、175.73%和936.49%;BBF组则显著增加了绿豆幼苗的地上部分鲜重和干重,分别提高了92.64%和179.67%。高通量测序结果显示,接种复合微生物菌剂BFF和BBF均显著提高了细菌群落的多样性和丰富度,同时降低了真菌群落的多样性。在门水平上,显著增加了黏球菌门(Myxococcota)的相对丰度,降低了接合菌门(Zygomycota)的相对丰度。在细菌属水平上,显著减少了罗河杆菌属(Rhodanobacter)的相对丰度,增加了黏液杆菌属(Mucilaginibacter)和慢生根瘤菌属(Bradyrhizobium)的相对丰度;在真菌属水平上,显著增加了隐球菌属(Cryptococcus)的相对丰度,同时降低了被孢霉属(Mortierella)和Gliocladiopsis的相对丰度。功能预测结果表明,接种复合微生物菌剂显著提高了根际细菌中的固氮作用,同时增加了致病-腐生-共生型真菌的相对丰度,降低了腐生型和腐生-共生型真菌的相对丰度。【结论】接种复合微生物菌剂可以提升土壤养分,调节根际微生物群落的结构和多样性,增加有益菌的数量,减少病原菌的存在,从而为绿豆幼苗创造更有利的根系生长环境,促进它们的生长发育。研究结果不仅为绿豆幼苗的生长提供了新的理论支持,也为复合微生物菌剂在农业生产中的应用提供了理论基础。     

Salt tolerance of the reed plant Phragmites communis

Reed plants ( Phragmites communis Trinius) were grown at NaCl concentrations up to 500 m M and their growth, mineral contents and leaf blade osmotic potential were determined. Addition of NaCl up to 300 m M did not affect growth significantly. Sucrose, Cl^-and Na⁺ concentrations in the shoots increased with the salinity of the medium and the shoot water content decreased. K⁺ always contributed most to the leaf osmotic potential. Even in the presence of 250 m M NaCl in the rooting medium, the leaf blade contained only 50 mM Na⁺, suggesting that the plants have an efficient mechanism for Na⁺ exclusion. ²²Na⁺ uptake experiments suggested that the retranslo-cation of absorbed Na⁺ from shoots to the rooting medium lowered the uptake of Na⁺.     

东北地区芦苇植硅体形态的空间差异

笔者对东北地区12个样点的芦苇叶片的植硅体进行了分析,探讨了芦苇植硅体在空间上的分布规律,揭示芦苇植硅体的环境指示意义,为定量恢复古环境提供参考。实验结果表明:12个样点中芦苇植硅体基本类型相同,共有5种主要植硅体类型,即中鞍型、帽型、芦苇扇型、尖型和棒型;但芦苇植硅体的浓度随着纬度的变化而相应的发生变化。总体来说,纬度较低的样点芦苇植硅体的浓度较大,而纬度较高的样点芦苇植硅体的浓度相对较小;随着纬度的变化,芦苇的特征植硅体中鞍型的浓度也呈现波状变化,牡丹江以南的几个样点中鞍型植硅体浓度相对较大,9、10两个月牡丹江以北的几个样点中鞍型植硅体浓度迅速减少。芦苇扇型植硅体则呈现出纬度较高的样点植硅体浓度较大,纬度较低的样点植硅体浓度较小的特点,芦苇扇型植硅体的空间变化规律与扇型植硅体的不同。     

盘锦湿地芦苇(Phragmites communis)群落蒸发散主导影响因子

利用2005年全年盘锦芦苇湿地梯度观测和涡动相关系统的监测数据,对芦苇群落的蒸发散变化规律及其主导影响因子分析表明,不同月份芦苇群落蒸发散日变化呈现出相同的变化趋势,即早晚低、中午高的单峰型曲线;芦苇群落蒸发散主要受当地气象因素、植被生长状况和生理生态特征的影响.相关分析表明,芦苇湿地蒸发散与净辐射、气温、地表温度、相对湿度、风速、土壤含水量等环境因素的变化都有很好的响应.回归分析表明影响生长季主要因素有:净辐射、土壤含水量、相对湿度、气温和地表温度;影响非生长季主要有:净辐射、地表温度和风速.同时,植被生长状况和生理生态特征对蒸发散也有显著影响,其中叶面积指数与气孔导度是芦苇群落蒸发散的主导影响因子.     

Cold tolerance and plant growth promotion potential of Serratia marcescens strain SRM (MTCC 8708) isolated from flowers of summer squash (Cucurbita pepo)

Aim: To determine the cold tolerance and plant growth promotion potential of Serratia marcescens strain SRM (MTCC 8708). Methods and Results: Serratia marcescens strain SRM was isolated from the flowers of summer squash plants, showing no apparent symptoms of yellow vine disease. It was evaluated for growth and plant growth promotion attributes at 15 and 4°C. At 15°C, the isolate was able to solubilize 76·6 μg ml^?1 of P and produce Indole Acetic Acid, IAA (11·1 μg ml^?1). HCN and siderophore production were also detected at 15°C. The isolate retained all the plant growth promotion traits at 4°C. Seed bacterization with the isolate significantly enhanced plant biomass and nutrient uptake of wheat seedlings grown in cold temperatures. Conclusion: Serratia marcescens strain SRM is a promising cold‐tolerant isolate that can significantly influence wheat seedling growth at cold temperatures. Significance and Impact of the Study: This strain can be employed as a bioinoculant in cold temperature conditions.