栽培花生Aux/IAA家族鉴定与生物信息学分析

Aux/IAA(Auxin/Indole-3-Acetic Acid)家族是生长素(Auxin)信号的早期响应基因家族之一,广泛参与调控植物的生长发育。然而目前对于栽培花生(Arachis hypogaea)Aux/IAA家族的研究还未见相关报道。本研究在栽培花生中共鉴定到了34个Aux/IAA基因,分布在15条不同的染色上。多重序列比对分析发现花生Aux/IAAs具有4个保守结构域,分别为Ⅰ-Ⅳ。聚类分析将花生Aux/IAAs分为Ⅰ-Ⅷ,8个亚家族。各个亚家族内部基因具有相似的保守基序,而基因之间的内含子/外显子结构存在差异。基于基因表达模式分析将栽培花生分为A和B两组基因,A组基因在花生各个组织的表达量都相对较高,而B组基因的表达具有组织特异性。基于以上结果,本研究将为进一步对Aux/IAA家族的基因功能研究提供科学依据。     

Soil–root cross‐talking: The role of humic substances

The biological activity of humic substances (HS) has been elucidated in the last 40 years. Growth enhancement from HS has been demonstrated in several plants in the laboratory and the field. Morphogenesis effects have also been investigated and include induction of lateral root formation and root hair initiation in intact plants and stimulation of root and shoot development in treated cell calluses. HS enhance nutrient use efficiency, aiding assimilation of both macro and microelements and promoting plant growth by the induction of carbon, nitrogen, and secondary metabolism. The review aims are to: (1) shed light on the mechanism by which plants “talk” with soil through humic substances, (2) elucidate the plant responses to the stimulatory effects of HS, the regulatory circuits that allow plants to cope with humus, and the feedback between plant community structures, and (3) show (in light of recent debate about the alkaline extraction of soil humic substances) the plant capability to acquire biologically active substances from soil. It will be shown that plants modify soils, creating and maintaining favorable habitats for growth and survival. Therefore, organic substances exuded by roots are not a wasteful loss of carbon and energy. They represent an evolved strategy by which plants “talk” to the soil. The mobilization of bioactive organic/humic substances from bulk soil or bulk humus is critical to plant and soil health.     

硼酸对绿豆下胚轴不定根发生的影响

本研究结果表明 :10 - 5～ 10 - 2 mmol L硼酸均可促进绿豆下胚轴不定根的发生 ,其中浓度为 10 - 3mmol L、10 - 2 mmol L的硼酸处理与对照相比有显著效果 ,不定根数目随着硼酸浓度的升高而增多 ;10mg LIBA与硼酸混合处理其促进生根的效果好于单独处理 ;硼酸处理对插条的过氧化物酶活性影响较小 ,在扦插第 1d、2d、7d时 ,能降低多酚氧化酶和IAA氧化酶活性 ,在扦插第 3d时其多酚氧化酶和IAA氧化酶活性高于对照 ,硼酸处理的插条内酚类物质、IAA含量在扦插第 1d、2d高于对照 ,在第 3d、7d时低于对照     

不同倍性白桦叶芽中IAA和ABA含量分析

[目的]初步比较二、三、四倍体白桦叶芽中IAA和ABA含量的差异,为研究植物内源激素在不同倍性白桦生长发育过程中所发挥的作用提供参考.[方法]利用HPLC法测定了二、三、四倍体白桦叶芽中IAA和ABA含量.[结果]对不同倍性白桦叶芽IAA与ABA含量的比较发现,多倍体白桦叶芽IAA含量均显著高于二倍体,而ABA含量则显著低于二倍体;单位质量的二、三、四倍体白桦叶芽中IAA/ABA的值分别为0.76、1.45、1.06.[结论]染色体倍数的增加对内源激素含量产生了重要影响.     

茉莉酸甲酯和脱落酸对绿豆下胚轴生长的影响

高浓度(10-4mol/L)的茉莉酸甲酯(methytyl jasmonate,MeJA)和(10^-4--10^-8mol/L)脱落酸(abxtsic acid，ABA)对绿豆下胚轴的生长均有抑制作用，ABA的抑制效果比MeJA明显。低浓度(10^-9--10^-7mol/L)的MeJA却有轻微的促进作用，但ABA有轻微的抑制作用。实验表明，MeJA影响下胚轴的生长，主要是通过胞壁的离子结合型的过氧化物酶和IAA氧化酶起作用，ABA则主要是通过可溶性POD和IAA氧化酶影响绿豆下胚轴的生长。     

红壤中产吲哚乙酸并具解磷作用的促生菌筛选鉴定及促生效果研究

从江西红壤花生地中,筛选出3株产吲哚乙酸(IAA)菌株,其中ZH5菌株具有较强分泌IAA的能力且性能稳定,培养24 h时IAA产量达到43.18μg/ml,且菌株ZH5具有较强的解磷能力。通过菌株形态、生理生化特征测定及16S r RNA的保守序列鉴定,初步确定菌株ZH5为巨大芽孢杆菌(Bacillus megaterium)。对菌株生长和发酵条件进行研究,结果表明促进菌株ZH5生长和增强分泌IAA的最佳培养条件基本一致,最佳培养条件初始p H为6~8,最佳通气量为50 ml/250 ml,30℃摇床培养24 h;最佳碳源和氮源分别是蔗糖和酵母粉。在实验室中进行盆栽试验,结果表明用ZH5菌株处理的花生株高增加了54.0%;植株鲜重增加了49.8%;并且ZH5菌株处理的花生植株全磷及花生根长、根尖数、根表面积及根体积均有显著增加,分别增加了21.84%、64.20%、28.20%、34.35%和68.67%。该研究结果为菌株ZH5在农业生产中的应用提供了理论依据和实验基础。     

高寒地区燕麦根际联合固氮菌研究Ⅱ固氮菌的溶磷性和分泌植物生长素特性测定

对分离自高寒地区燕麦根际的8株联合固氮菌株溶磷性和分泌植物生长素特性进行了测定,结果表明,菌株Azotobacter sp.ChO4、Azotobacter sp.ChO5和Azospirillus lipoferum ChO6具有溶磷能力,但溶磷强度差异较大 (83.8～103.5 μg/mL),Azospirillus lipoferum ChO6溶磷能力较Azotobacter sp.ChO5和Azotobacter sp.ChO4强;8株菌株均具有分泌植物生长素特性,但能力差异较大 (2.16～17.31 μg/mL),只有Pseudomonas sp.ChO3和Azospirillus lipoferum ChO6分泌IAA的浓度较高(大于10 μg/mL).研究认为,菌株Pseudomonas sp.ChO3、Azotobacter sp.ChO4、Azotobacter sp.ChO5、Azospirillus lipoferum ChO6和Azospirillus brasilense ChO8等在燕麦菌肥研制方面具有较大的开发潜力.     

一株植物促生菌的筛选、鉴定及其对花生的促生效应研究

从南京板桥镇自然条件下的潮土中,筛选出JX15菌株,具有较强分泌IAA的能力且性能稳定,20 h分泌IAA达到22.55μg/ml,并兼具解磷能力。经形态观察、部分生理生化特征测定及16S rRNA的保守序列鉴定,初步确定该菌株为巨大芽孢杆菌(Bacillus megaterium),GenBank登录号为JX424613。设置单因素试验对菌株生长和发酵条件进行初步研究,结果表明促进菌株JX15生长和增强分泌IAA的最佳培养条件基本一致,最佳培养条件是初始pH 7~8,装液量为50 ml/250 ml,30℃摇床培养24 h;最佳碳、氮源分别是甘露醇和酵母粉。在实验室条件下进行花生盆栽试验,结果表明接种JX15菌液的处理,花生植株较未接种菌液的处理其鲜重、株高、全氮、磷、钾及花生根系总长度、根平均直径、根表面积和根尖数均有显著增加。研究结果为该菌株的工程应用提供了理论依据。     

Efficient genetic transformation of Jatropha curcas L. by microprojectile bombardment using embryo axes

An efficient and reproducible protocol was established for genetic transformation in Jatropha curcas through microprojectile bombardment. Decotyledonated embryos from mature seeds were pre-cultured for 5 days and elongated embryonic axis was subjected to bombardment for the optimization of physical parameters. The frequency of transient gus expression and survival of putative transformants were taken into consideration for the assessment of physical parameters. Statistical analysis reveal that microcarrier size, helium pressure and target distance had significant influence on transformation efficiency. Among different variables evaluated, microcarrier size 1 μm, He pressure 1100 and 1350 psi with a target distance of 9 and 12 cm respectively were found optimum by co-relating microcarrier size, helium pressure and target distance on the frequency of gus expression and survival of putative transformants. Selection of putative transformants was done with increasing concentrations (5-7 mg L⁻¹) of hygromycin. The integration of desired gene into Jatropha genome was confirmed with PCR amplification of 0.96 and 1.28 kb bands of hptII and gus gene respectively from the T₀ transgenics and Southern blot analysis using PCR amplified DIG labeled hptII gene as a probe. A successful attempt of genetic transformation was made with optimized conditions using particle gene gun and establishing a stable transformation in J. curcas with 44.7% transformation efficiency. The procedure described will be very useful for the introgression of desired genes into J. curcas and the molecular analysis of gene function.     

吲哚乙酸对水稻花后剑叶光合产物输配作用的示踪动力学研究

运用示踪动力学分析方法，分析吲哚乙酸涂稻穗与剑叶后，剑叶中几种光合产物的变化情况，结果表明，吲哚乙酸涂稻穗后，能促进可输配物质的形成，抑制暂不输配物质的形成，对结构物质，呼吸消耗与光合产物输出具交替作用。吲哚乙酸涂剑叶后，能促进可输配物质、结构物质的形成，并对光合产物的输出具促进作用，对暂不输配物质与呼吸消耗也具交替作用。