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991.
基于营养竞争原理的大豆根腐病生防芽孢杆菌的筛选及其特性研究 总被引:4,自引:0,他引:4
利用营养竞争平板筛选法获得了可在大豆麦麸(SWB)培养基上快速生长并拮抗大豆根腐病菌Fusarium oxysporum和F.solani的芽孢杆菌菌株B006和B010。通过16S rDNA序列分析、形态观察和生理生化性状测定,将其鉴定为枯草芽孢杆菌(Bacillus subtilis)。田间小区试验结果表明,以种子处理(108cfu/mL,药种比为1∶60)和以麦麸为载体的固体菌剂土壤沟施(106cfu/g,用量195 kg/ha)B006和B010菌剂对真叶期大豆根腐病的防治效果分别为74.6%和63.5%,高于商品化学农药35%多福合剂种子处理的防效(P=0.05),大豆产量分别增加13.8%和24.0%。利用特异引物对生防功能基因的扩增结果表明,bmyB、fenD、bioA和srfAA基因以及srfAB基因簇的片段在2个菌株中均存在,而ituC基因仅存在于B010菌株中。对菌株生防功能基因的分析有助于今后高效菌株的快速筛选和对生防菌作用机制的研究。 相似文献
992.
吡虫啉对番茄幼苗根系活力及生理生化指标的影响 总被引:7,自引:0,他引:7
本论文以70%吡虫啉水分散粒剂为研究药剂,以番茄为研究试材,通过室内盆栽法研究了不同剂量的吡虫啉对番茄植株生长量的影响,以及对番茄体内过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和番茄根系活力进行了测定。结果表明70%吡虫啉水分散粒剂分别以有效成分用量1.0、1.5、2.5、3.0mg/株和5.0mg/株5个剂量处理番茄幼苗,在处理后30d测定番茄展开叶片数、株高、主根长、地上和地下部分鲜重,随着药剂浓度的增加,各测定指标呈现先升高后降低的变化趋势,其中以2.5mg/株剂量影响最大,与清水对照比差异显著。测定不同浓度的吡虫啉处理番茄后30d叶片及根系中CAT、SOD的活性和根系活力,结果表明不同剂量的吡虫啉均对番茄叶片和根系的CAT、SOD活性和根系活力有一定的影响,其效应并不是随药剂浓度的增加而增加,与清水对照比以2.5mg/株剂量各生理指标活性增加最大,超过2.5mg/株的剂量有下降趋势。 相似文献
993.
ABA及Ca~(2+)/CaM信使系统对高温逆境下棉苗根系生长的调控 总被引:1,自引:0,他引:1
以对温度敏感的杂交棉——标杂A2为研究对象,在人工气候箱培养条件下,研究了ABA和Ca2+/CaM信使系统对热激条件下棉花苗期根系抗逆生理性状的影响及调控。结果表明:在高温逆境条件下,棉株体内可以产生ABA而提高棉苗耐热性;外源ABA或Ca2+可以减轻棉苗根系热激危害,提高根系活力、基部伤流强度及根系活性恢复力,降低根系电解质外渗率;ABA和Ca2+具有明显的互作效应,棉苗对变温逆境的抗性可能通过ABA及Ca2+/CaM信使系统诱导产生并起作用;钨酸钠、LaCl3和CPZ分别是ABA和Ca2+/CaM信使系统的抑制剂,外源喷施对棉苗的耐热性具有减弱作用。复水前后的棉苗基部伤流强度能够较好地反映根系代谢活性,可以作为棉苗耐热性鉴定的有效指标。 相似文献
994.
Vertical Distribution and Seasonal Dynamics of Fine Root Parameters for Apple Trees of Different Ages on the Loess Plateau of China 总被引:1,自引:0,他引:1
The vertical distribution pattern and seasonal dynamics of fine root parameters for the apple trees of different ages (3, 10, 15, and 20 years old) on the Loess Plateau of China were studied. Soil coring method was used to determine the vertical distribution and seasonal dynamics of fine roots at different root radial distances (1.0, 1.5, and 2.0 m from the main tree trunk). The fine root biomass density (FRD), fine root length density (RLD), and specific root length (SRL), as well as soil water content and soil temperature were also measured. The FRD and RLD for the 10, 15, and 20 years old trees reached peak values in the 20-30 cm soil layer. For the 3 years old tree, the highest FRD and RLD were observed in the 10-20 cm soil layer. The FRD and RLD decreased with increased soil depth from the 10-20 or 20-30 cm soil layer for all age apple trees. The SRL declined with the increase of tree age. The FRD at the 1.0 m radial distance from the main tree trunk was higher than that at other radial distances in the 3 and 10 years old orchard. However, in the 15 and 20 years old orchards, especially the 20 years old orchard, the FRD at the 2.0 m radial distance was nearly equal to or higher than that at the 1.0 and 1.5 m radial distances. For all the root radiuses or the tree ages, the FRD, RLD, and SRL were the highest in spring and the lowest in autumn. The age of an apple tree does not affect the vertical distribution pattern but the biomass of fine roots and the SRL. Radial distance affects the root horizontal distribution of 3 and 10 years old trees but the 15 and 20 years old trees. Additionally, effects of soil temperature and soil moisture on fine root distribution or seasonal dynamics are not significant. 相似文献
995.
Effect of Inoculation with Arbuscular Mycorrhizal Fungus on Nitrogen and Phosphorus Utilization in Upland Rice-Mungbean Intercropping System 总被引:2,自引:0,他引:2
The effect of arbuscular mycorrhiza fungi (AMF) on plant growth and nutrition utilization in upland rice and mungbean intercropping system was studied. A pot experiment was conducted in the greenhouse and AMF colonization rates of rice and mungbean roots, plant nutrient contents, the ability of nitrogen fixation, and nutrient contents changed in the soil were analyzed. The results were obtained as follows: the rates of AMF colonization of rice and mungbean roots were reached to 14.47 and 92.2% in intercopping system, and increased by 4.11 and 11.95% compared with that of in monocropping; the nirtrogen contents of mungbean and rice were increased by 83.72 and 64.83% in shoots, and 53.76 and 41.29% in roots, respectively, while the contents of iron in shoot and root of mungbean were increased by 223.08 and 60.19%, respectively. In the intercropping system with inoculation of AMF, the biomass of mungbean increased by 288.8%. However, the biomass of rice was not significantly changed among all treatments with or without inoculation of AMF recorded. The number and dry weight of nodules were significantly increased either when mungbean was intercropped with rice or inoculated with AMF. When compared with that of monocropping without AMF inoculation, the contents of nitrogen, phosphorus and iron in nodules of intercropping mungbean with inoculation increased by 80.14, 69.54 and 39.62%, respectively. Additionally, intercropping with AMF inoculation significantly increased soil nitrogen content, but reduced soil phosphorus content. We concluded that upland rice-mungbean intercropping system and inoculation with AMF improved the nutrient uptake, the ability of nitrogen fixation and the growth of mungbean. 相似文献
996.
Effects of soil moisture on cotton root length density and yield under drip irrigation with plastic mulch in Aksu Oasis farmland 总被引:2,自引:1,他引:1
Effects of soil moisture on cotton root length density (total root length per unit soil volume) and yield under drip irrigation with plastic mulch were studied through field experiments. The results indicate that spatial distributions of root length density of cotton under various water treatments were basically similar. Horizontally, both root length densities of cotton in wide and narrow rows were similar, and higher than that between mulches. Vertically, root length density of cotton decreased with increasing soil depth. The distribution of root length density is different under different irrigation treatments. In conditions of over-irrigation, the root length density of cotton between mulches would increase. However, it would decrease in both the wide rows and narrow rows. The mean root length density of cotton increased with increasing irrigation water. Water stress caused the root length density to increase in lower soil layers. There is a significant correlation between root length density and yields of cotton at the flower-boll and wadding stages. The regression between irrigation amount and yield of cotton can be expressed as y = -0.0026x2+18.015x-24845 (R2 = 0.959). It showed that the irrigation volume of 3,464.4 m3/hm2 led to op-timal root length density. The yield of cotton was 6,360 .8 kg/hm2 under that amount of irrigation. 相似文献
997.
无纺布限根栽培对西瓜根域温度、植株生长和果实品质的影响 总被引:1,自引:0,他引:1
以‘香秀’西瓜为材料,研究了无纺布限根栽培对西瓜根域温度、植株生长和果实品质的影响。结果表明:与对照组相比,无纺布限根栽培显著提高了地表下5、15和25 cm处的根域温度,其平均根域温度提高了2.31℃。西瓜植株早期的生长过程中茎长、叶片数和相对叶面积与对照相比均有不同程度的提高。西瓜的根系也受到限根栽培的影响,限根组的根系主要分布在地表下28 cm内的耕作层,主根系较短,侧根系发达,单位根域体积内根系密度较大,根系活力高。限根栽培显著改善了果实的品质,果实的可溶性固形物含量、出汁率、Vc含量和类黄酮含量均与对照组达到了差异的极显著或显著水平。无纺布限根栽培对西瓜果实的大小、可滴定酸含量和番茄红素含量均没有显著影响。 相似文献
998.
以红麻细胞质雄性不育系P3A、恢复系992及其杂交种为材料,采用水培法研究了红麻杂交种根系生长对盐胁迫的抗性优势表现。揭示不同程度盐胁迫对红麻杂交种根系生长的影响,以期为红麻杂种优势利用及耐盐红麻杂交种的培育提供理论参考。结果表明:在盐胁迫下,不同基因型对盐胁迫的耐性存在明显差异;红麻杂交种幼苗的根长、根表面积、根体积和根尖数等均优于亲本,存在明显的杂种优势,表现出较强的中亲优势和超高亲优势;随着盐浓度的提高,杂交种与亲本间差异达到显著水平。说明在一定阈值内,红麻杂交种根系生长在盐胁迫下明显表现出比亲本较强的耐性,红麻杂交种在耐盐性方面具有杂种优势。同时盐胁迫改变了红麻根系的形态构型,使根系趋于简单化,可以有效增加根系生长形成更多的粗根,提高其耐盐能力。研究结果为通过杂交育种获得更加耐盐的红麻材料提供了依据。 相似文献
999.
1000.
以葡萄水晶、金手指、康拜尔为材料,采用沙培试验法,探讨了葡萄根系对锰胁迫的生理反应。结果表明:随着锰质量浓度的升高,3种葡萄根系活力均呈先升后降的趋势,在锰的质量浓度为5 g/L时其根系活力达到最大。锰处理整体上增加了3种葡萄根中MDA含量。在锰胁迫下,PAL活性在不同品种间呈现出不同的变化:水晶和康拜尔先升高后降低,金手指却恰恰相反。总之,金手指根系对锰胁迫最敏感,更易受到伤害,而水晶和康拜尔却不太敏感,说明水晶和康拜尔对锰胁迫有较强的耐性。 相似文献