接种苜蓿中华根瘤菌SD101对提高紫花苜蓿结瘤数和产量的影响

为提高紫花苜蓿品种的结瘤率和产量,建立高效紫花苜蓿与苜蓿根瘤菌的共生固氮体系,本研究采用16S r DNA测序方法得知已获得的SD101为苜蓿中华根瘤菌。通过盆栽试验研究了紫花苜蓿品种‘敖汉’和‘龙牧801’在不同处理基质中接种苜蓿中华根瘤菌SD101和保护剂的结瘤和株高情况。通过田间小区试验研究了‘敖汉’和‘龙牧801’在接种苜蓿中华根瘤菌SD101和保护剂后田间的结瘤和产量情况。结果发现,接种了SD101和保护剂的‘敖汉’和‘龙牧801’在不同基质上都有很好的结瘤数和株高,达到了显著水平。尿素处理的结果表明,施用尿素对苜蓿与根瘤菌共生结瘤有一定的抑制作用。使用伽马射线处理土样能够达到彻底灭菌的效果。田间试验中土著根瘤菌在苜蓿生长的过程中起着重要作用,但是使用苜蓿根瘤SD101和保护剂拌种的处理有着更强的竞争性。     

接种中华根瘤菌SD101和避光对紫花苜蓿固氮和光合作用的影响

为了研究光合和氮素互作对紫花苜蓿自身生长和光合作用的影响,以紫花苜蓿品种WL319为试验材料,通过接种中华根瘤菌SD101和避光处理相结合,测定接种中华根瘤菌SD101紫花苜蓿在非避光、避光和复光条件下的生长情况和光合指标。研究结果表明,非避光条件下,接种中华根瘤菌SD101能够显著提高紫花苜蓿的地上生物量、叶片中叶绿素含量和紫花苜蓿的光合能力;避光条件下,受气孔导度和非气孔等因素的影响,中华根瘤菌SD101不能发挥其与紫花苜蓿共生固氮的优越性,光合速率比不接种中华根瘤菌SD101对照低。恢复光照后,接种中华根瘤菌SD101的紫花苜蓿光合作用恢复程度没有不接菌对照好。由此可见,紫花苜蓿与中华根瘤菌SD101的共生固氮作用需要在适宜的光照下才能促进紫花苜蓿生长和光合作用。     

接种不同根瘤菌对紫花苜蓿固氮效能及生物量的影响

为了在晋北生态区给主要推广品种筛选适宜的高效根瘤菌,使紫花苜蓿-根瘤菌共生体充分发挥共生固氮作用,建立高效、高产、优质紫花苜蓿生产体系。将中国农业科学院菌种保藏中心筛选出的9株紫花苜蓿根瘤菌作为试验材料,以山西大同地区的土壤为基质,结合温室盆栽和田间试验,比较供试材料的结瘤数、固氮酶活性、株高、生物量等指标的变化情况。筛选出适合供试材料巨能耐盐紫花苜蓿品种的4株高效根瘤菌CCBAU30015、CCBAU NMC024-1、HBU07004和CCBAU30198,并将这4株菌进行田间接种效果验证。结果表明,接种CCBAU30015、CCBAU NMC024-1、HBU07004和CCBAU30198后,全年干草产量分别比对照增加18.7%,15.8%,11.3%和13.3%,单位面积蛋白质产量分别比对照增加10.9%,10.2%,9.7%和10.1%,其中,CCBAU30015表现最为突出,在各个指标上与对照间差异均显著(P0.05)。说明通过土壤筛选的高效根瘤菌可以应用到实际生产中。     

BOX-PCR分子标记对补播紫花苜蓿共生根瘤菌田间竞争结瘤能力的研究

本研究利用SX01、HB02 两株根瘤菌菌株对山西右玉草地补植的紫花苜蓿中苜一号进行了田间接种试验.为了检验根瘤菌菌株的接种效果和筛选高效紫花苜蓿根瘤菌菌株,采用BOX-PCR分子标记方法对接种根瘤菌菌株的田间竞争结瘤能力进行了研究.通过对接种供试菌株及田间分离获得的根瘤菌菌株进行BOX-PCR及不同菌株之间的BOX分...     

甘蔗/菜用大豆间作条件下根瘤菌与大豆品种匹配性研究

为了提高间种条件下甘蔗和菜用大豆的经济效益,筛选出在菜用大豆与甘蔗间作模式下与菜用大豆相匹配的菌肥,以2个根瘤菌菌肥CW和XFN-1和2个菜用大豆品种‘七星1号’和‘华春4号’为材料,研究了在菜用大豆与甘蔗间作模式下品种与根瘤菌菌肥的匹配性。结果表明：在菜用大豆与甘蔗间种下,接种CW和XFN-1根瘤菌菌肥使‘七星1号’和‘华春4号’2个品种的结瘤能力都显著提高;‘七星1号’的产量接菌后降低,不显著,而‘华春4号’接种CW根瘤菌菌肥后产量显著提高。这说明评价根瘤菌菌肥与大豆品种的匹配性应以产量指标为主要依据,直接利用大豆品种的结瘤能力不能很好地评价菌肥与品种的匹配性,因此‘七星1号’与CW和XFN-1根瘤菌菌肥不匹配,‘华春4号’与CW根瘤菌菌肥匹配性好。间作条件下,‘华春4号’不接菌处理每公顷鲜荚和荚秆产量分别为7846.9 kg和9499.9 kg,效益分别为28249元和19000元;‘华春4号’接种CW根瘤菌菌肥后每公顷鲜荚和荚秆产量分别为9418.0 kg和11172.0 kg,效益分别为33905元和22344元;收获鲜荚的效益远高于收获荚秆的效益,接种CW根瘤菌菌肥比不接菌处理增收20%。‘华春4号’接种CW根瘤菌菌肥,大豆单株多粒荚数、多粒荚重、百粒鲜重都显著提高,而其他农艺性状无影响,说明生物固氮的氮素能够协调大豆营养生长和促进生殖生长,从而显著提高大豆产量。     

不同根瘤菌接种量对紫花苜蓿的影响

紫花苜蓿接种根瘤菌试验结果表明：接种根瘤菌可以提高紫花苜蓿的结瘤率、单株结瘤数、单株根瘤重、生长速度和产量，并且接种根瘤菌的量为20g／hm^2时，作用比较明显。     

六株耐酸苜蓿根瘤菌的筛选及生长特性研究

为获得能够使紫花苜蓿在酸性土壤中高效结瘤的耐酸根瘤菌,该研究从酸性土（pH5.2）上生长的紫花苜蓿根瘤中分离到若干菌株,利用根瘤菌对酸的适应性耐受反应筛选到六株能够在pH4.8的固体培养基上稳定生长的菌株,并检测了这六株菌的结瘤特征、不同酸度下的生长曲线和平均代时。结果表明,六株根瘤菌均能使紫花苜蓿植株结瘤,使其具有较多的结瘤数（≥10个/株）和较高的结瘤率（66.67%~100%）;不同酸度下,六株根瘤菌呈现不同的生长特性,酸显著降低根瘤菌的生长速率,使其生长延滞期增长,对数生长期出现滞后,稳定期到达延迟,酸性条件下各根瘤菌的平均代时均较中性条件下的长,环境pH越低,菌株平均代时越长。然而,在低pH条件下,耐酸根瘤菌在其耐受酸度范围内经过延长的延滞期后仍然能够较快地生长     

转CpFATB基因苜蓿后代抗寒性分析

为明确腊梅硫酯酶基因(Cp FATB)在苜蓿中的表达特点及生理功能,获得苜蓿抗寒育种的基因资源。本实验通过根癌农杆菌介导将Cp FATB转入‘龙牧806’、‘WL319HQ’和‘肇东’3个苜蓿品种中,对其后代进行抗寒性鉴定。结果表明,3个苜蓿品种转Cp FATB基因SP3代(第三代基因修饰材料)种子发芽率、简化活力指数均高于各自对照,其中T‘龙牧806’最高,达到87.79%、208.19;转基因植株叶绿素a、叶绿素b及叶绿素总量显著低于其各自对照苜蓿品种,根系可溶性糖、可溶性蛋白、游离脯氨酸含量显著高于其各自对照苜蓿品种;转Cp FATB基因植株高度和分枝数与其各自对照差异不显著,而越冬率显著高于其各自对照品种,T‘龙牧806’越冬率最高,达到96.60%。转Cp FATB基因促进‘龙牧806’、‘WL319HQ’、‘肇东’苜蓿SP3代种子萌发;抑制苜蓿叶片叶绿素合成。越冬前促进根系可溶性糖、可溶性蛋白、游离脯氨酸含量积累,增强POD、SOD活性,提高了翌年越冬率,说明外源Cp FATB基因有助于苜蓿抗寒性的提高。     

10个紫花苜蓿品种耐盐性的比较研究

对10个紫花苜蓿品种种子分别用0%、0.3%、0.7%和1.0%的NaC l溶液进行处理,通过种子发芽率、相对发芽势、幼苗重和幼苗高对各品种种子萌发期耐盐性进行了研究。结果表明:用0.7%或1.0%NaC l溶液性鉴定较为合理;0.7%NaC l溶液处理苜蓿种子,其幼苗重和幼苗高可作为苜蓿品种耐盐的鉴定指标。0.7%、1.0%NaC l溶液处理下,通过测定第3天和第5天各品种种子的发芽势,可以鉴定耐盐性大小。对10个苜蓿品种耐盐性综合研究结果是:龙牧801和巨人201的耐盐性最强,其次是肇东、龙牧803和CW 200;新疆大叶和爱菲尼特的耐盐性最弱。     

应用综合指标法和灰色关联度法对10个紫花苜蓿品种进行耐盐性评价

紫花苜蓿是一种主要绿肥作物,在改良盐碱地中发挥着重要的作用。选择中苜1号、阿尔岗金、敖汉、先行者、皇后、WL343HQ、德宝、三得利、赛迪5、惊喜10个紫花苜蓿品种,对其萌发期和生长期的耐盐性测试分析,以期为盐碱地种植适宜的紫花苜蓿品种提供理论依据。主要用综合指标法和灰色关联度法,通过计算7个性状指标即相对发芽率、相对发芽速度、单位面积田间生物量、株高、叶茎比、干鲜比和叶绿素含量,对10个紫花苜蓿品种的耐盐性进行综合评价。两种方法都表明WL343HQ、中苜1号、德宝、先行者的耐盐性好,敖汉的耐盐性最差。综合实验室和田间苜蓿的生长表现,认为灰色关联度法较综合指标法适合评价苜蓿的耐盐性。     

不同诱变处理对苜蓿叶绿素含量及光合作用的影响

为研究60Co-γ射线、紫外线、零磁空间和EMS诱变处理对苜蓿SP1代叶片叶绿素含量及光合作用的影响,筛选最优诱变处理梯度,选育适合高寒地区种植的苜蓿新品系或品种。以‘公农1 号’、‘Wega7F’、‘WL319HQ’、‘敖汉’4 个苜蓿品种试验材料,设置60Co-γ射线150、300、450 Gy射线强度,紫外线30、60、90 min 照射时间,EMS 0.1%、0.2%、0.4%(v/v)溶液浓度,零磁空间处理180 天;测定苜蓿叶片叶绿素a、叶绿素b、叶绿素总量、叶绿素a/b 值以及净光合速率。结果表明,‘公农1 号’450 Gy60Co-γ处理、紫外线处理时间为30 min和0.4%EMS处理下叶绿素a 含量最高,均高于对照3.17 mg/g,但与对照差异不显著,其他处理均低于对照。‘Wega7F’在紫外线60 min 时间处理下,叶绿素b 值明显增加,且显著高于其他处理(P<0.05)。‘公农1 号’在450 Gy 60Co-γ辐射处理下叶绿素含量最高,a/b 比值最小,其他3 个品种在150 Gy处理下叶绿素含量最高,但a/b 比值最小。各苜蓿品种不同诱变处理净光合速率大小依次为：60 min 紫外线处理的‘Wega7F’>零磁空间处理的‘敖汉’>0.4%EMS 处理的‘WL319HQ’>0.4%EMS处理下的‘公农1 号’。150 Gy60Co-γ射线、60 min 紫外线、0.4%浓度EMS处理为苜蓿正向变异处理,有利于筛选有益诱变突变体。     

Behaviours of Medicago truncatula–Sinorhizobium meliloti Symbioses Under Osmotic Stress in Relation with the Symbiotic Partner Input: Effects on Nodule Functioning and Protection

Three genotypes of the model legume Medicago truncatula were assessed for symbiotic effectiveness in cross inoculation with two strains of Sinorhizobium meliloti under mannitol-mediated osmotic stress. Symbioses showed different tolerance levels revealed on plant growth, nitrogen-fixing capacity and indices of nodule functioning and protection. The variability of stress response was essentially correlated with performance at non-stressful conditions. Symbiosis attitude depended on bacterial partner, host-plant genotype and their interaction. Plant genotype manifested the highest contribution to symbiotic efficiency indices under osmotic stress, even for nodulation and nitrogen fixation where the bacterial strain effect is highly pronounced. Contrasting (tolerant/sensitive) associations were identified for tolerance behaviours, involving the same plant genotype with different rhizobial strains and vice versa. In nodules, osmotic stress leads to accumulation of oxidized lipids and decrease in total protein and leghaemoglobin contents. Antioxidant responses were manifested as induction of guaiacol peroxidase (POX, E.C. 1.11.1.7) and superoxide dismutase (E.C. 1.15.1.1). POX induction was higher in tolerant symbioses and both enzymes were suggested as contributors to the protection of nodule integrity and functioning under osmotic stress. In conclusion, symbiotic efficiency in M. truncatula–S.   meliloti combinations under osmotic stress is determined by each symbiont's input as well as the plant–microbe genotype interaction, and POX induction could prove a sensitive marker of tolerant symbioses.     

Soybean-Rhizobium Combination for Tolerance to Low P-High Aluminum

Two greenhouse experiments were conducted to evaluate the performance of selected soybean- Bradyrhizobium combinations in a soil having low P-high aluminum stresses under controlled conditions. Growth parameters such as plant height, nodule numbers, dry weight, nitrogenase activity and seed yield were used as an index. Three selected acid (low P-high Al) tolerant ( Essex, Tracy and Bedford ) and three sensitive ( Peking, Hill and McNair 600 ) soybean ( Glycine max ) varieties were sown in each pot. Three of the most tolerant strains of Bradyrhizobium (USDA 6, 110, 122), a mixture of these strains, and a commercial inoculant (Nitragin) were used to inoculate the Hartselle sandy loam soil. The results indicated that soil acidity significantly affected the soybean Bradyrhizobium symbiosis. The combination of variety Tracy plus Nitragin (mixed-strain) produced the highest and variety Peking plus mix-strain Nitragin the lowest plant height at all pH levels. Plants inoculated with Nitragin had higher shoot dry weight and seed yields. Variety Essex in combination with Nitragin produced the highest seed yields at all pH levels. Plants inoculated with Nitragin developed significantly more nodules than the other strains except for variety Peking. There was no significant difference in total nodule numbers between tolerant and sensitive soybean varieties at all soil pH levels except for Nitragin. Shoot total N did not increase by increasing the pH level or by using different variety-strain combinations.     

水分胁迫下紫花苜蓿根系特征与ABA含量的变化

研究通过温室盆栽试验探讨了干旱胁迫对‘三得利’、‘敖汉’和‘中苜1 号’3 个紫花苜蓿品种根系ABA浓度和根系特征的影响。按照田间持水量的100%（对照）、85%（轻度干旱）、70%（中度干旱）和55%（重度干旱）设置4 个梯度的水分胁迫处理,分别对3 个紫花苜蓿品种进行处理,并对根系ABA含量和根系性状进行测量。结果显示：水分胁迫可以显著影响不同生长时期的紫花苜蓿根系ABA的含量。随着处理时间的延长,不同水分胁迫处理的紫花苜蓿根系ABA含量均呈先升高后下降再升高的趋势。在移栽后的第75 天,根系ABA含量达到首个峰值,然后开始下降,到第105 天的时候将至最低,然后开始回升直至处理结束。移栽105 天以后,4 个水分胁迫处理（W1、W2、W3 和W4）紫花苜蓿根系ABA含量分别为44、56.6、64.6、94.4 ng/g FW。同时,不同紫花苜蓿品种根系ABA含量存在差异。移栽105 天以后,‘敖汉’、‘三得利’和‘中苜1 号’根系ABA含量均达到最低,分别为83.2 ng/g FW、61.7 ng/g.FW 和49.9 ng/g FW;之后,根系ABA含量开始回升。与对照相比,重度水分胁迫使根系长度降低了20.92%,使侧根数降低了20.71%,使根鲜重降低了43.79%,使根干重降低了37.96%。重度水分胁迫下植株根冠比是对照的1.9倍,这说明水分胁迫对地上部茎叶的影响要大于地下部的根系。水分胁迫降低了紫花苜蓿根长、侧根数、根鲜重和根干重,增加了紫花苜蓿根冠比,促使根系ABA含量升高。不同紫花苜蓿品种根系ABA含量存在差异。     

Evaluation of Rhizobium mdiloti Strains Isolated from Indigenous Populations in Northern Greece

Eight different Rhizobium meliloti strains (designated as strains 3, 6, 8, 15, 17, 18, 19 and 22) were isolated from fields cultivated with alfalfa. The growth characteristics of the isolated strains under different NaCl concentrations were investigated. Strains 15 and 22 showed marked tolerance to high NaCl concentration.
Symbiosis of one alfalfa variety ( Medicago sativa cv. Ipati ) inoculated with these strains showed marked differences in nitrogen fixing characteristics (nodule number, dry weight and total nitrogen content). Strains 8, 15 and 22 demonstrated the best performance with respect to all characteristics examined.
The supply of low levels of nitrate to inoculated alfalfa plants affected all the nitrogen fixing characteristics. Nodule number per plant decreased and the ranking of the different strains with respect to nodule number was altered. Dry weight was significantly increased by the supply of the nitrate, even in the case of symbioses with the highly effective strains 8, 15 and 22. Total nitrogen content was increased by the supply of nitrate. This increase was higher in plants inoculated with the less effective strains.     

Cultivar × rhizobial strain interactions in peas with respect to early symbiosis, nodule initiation and N uptake

Sixteen pea cultivars differing in their phenotypic characteristics were studied in order to characterize the cultivars' variability in symbiotic characters using three Rhizobium leguminosarum biovar viceae strains. The peas did not show any cultivar × strain interactions with the rhizobial strains used with respect to root hair infection frequency or day of nodule initiation. Three cultivars had high root hair infection frequencies, and five had only a few infected root hairs. Four of five leafless/semi-leafless varieties investigated and one cultivar with normal leaves formed nodules quickly, whereas three varieties with normal leaves formed nodules slowly. Ten of the cultivars showed cultivar × strain interactions with respect to N uptake, indicating that the performance of the N2-fixing symbioses depends on the rhizobial partner. Six cultivars showed cultivar × strain interactions with respect to dry matter production and the nodule proportion of the dry matter. Of the cultivars investigated, we conclude that some of the leafless/semi-leafless varieties (‘Capella’, ‘Filby’ and ‘Solara’) are suitable for inclusion in a future breeding programme, since these cultivars combined several important symbiotic characters.