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John W.PATRICK 《浙江大学学报(农业与生命科学版)》1990,(4)
The instablity of the stimulation of photosynthate unloading from seed coats of Phaseolus vulgaris by abscisic acid (ABA ) and benzylamino purine ( BAP ) was studied in terms of experimental conditions. ABA stimulated photosynthate unloading at pH 6 and pH 8 without close dependence upon pH. ABA at a concentration range of 10-5-10-4 mol/L displayed stimulatory effect. However, BAP revealed no effect at a concentration range of 10-6-10-4 mol/L. Experiments designed with different transport time of 14C-photosynthate indicated that ABA might act at the plasma membrane of the unloading cells. Reducing endogenous ABA level by diminishing leaf area did not facilitate the manifestation of exogenous ABA function. Potassium ion stimulated photosynthate unloading from seed coats with highest promotion at 100 mmol/L K . However, no dependence of ABA stimulation of photosynthate unloading on K was found. 相似文献
3.
Genetic variability within Phaeoisariopsis griseola from Central America and its implications for resistance breeding of common bean 总被引:1,自引:0,他引:1
The genetic and virulence variability of 112 isolates of Phaeoisariopsis griseola , collected from various locations in Central America, were studied using seven random amplified polymorphic DNA (RAPD) primers and 12 common-bean differential genotypes. Broad molecular diversity ( H = 0·92) among isolates was found using RAPD markers. Fifty pathotypes were identified on 12 differential bean genotypes, 29 of which were represented by only one isolate. Only 18 pathotypes were found in two or more countries. Pathotype 63-63 was the most virulent and caused leaf spots on all 12 common-bean differential genotypes. Comparison of virulence phenotypes and RAPD profiles to known Andean P. griseola isolates confirmed that all isolates belonged to the Mesoamerican group. Pairwise comparison between individual RAPD loci showed that the majority were in gametic phase linkage disequilibrium, revealing that P. griseola maintains a genetic structure that is consistent with asexual reproduction. The molecular and virulence diversities of P. griseola isolates from Central America imply that using single resistance genes to manage angular leaf spot is inadequate and stacking resistance genes may be necessary to manage the disease effectively. 相似文献
4.
引起糖甜菜细菌性叶斑病的萎蔫短小杆菌新致病变种 总被引:3,自引:0,他引:3
1995年在内蒙古临河市新发现了糖甜菜细菌性叶斑病,从病斑所分离的10个细菌菌株经柯赫氏法则验证,均确系该病的病原菌。采用形态观察、表型特征和生理生化特性测定、数值分析、血清学反应、细胞化学成分分析、DNA G+C mol%和DNA-DNA同源性测定进行了鉴定,并与植物病原棒形细菌15个标准菌株进行了比较。该病原菌为革兰氏阳性细菌,不规则短杆状,有一根鞭毛、亚极生或侧生,结合其生理生化特性、细胞化学成分和DNA G+C mol%和DNA-DNA同源性测定结果,认为应属于短小杆菌属(Curtobacterium)的萎蔫短小杆菌(Cur. flaccumfaciens),数值分析也支持这一结论。此外,据血清学反应结果及其对短小杆菌属的其它植物寄主的致病情况,认为该病原菌应是萎蔫短小杆菌种下的一个新的致病变种,定名为Curtobacterium flaccumfaciens pv. beticola pv. nov. Chen et al.,2000(萎蔫短小杆菌糖甜菜致病变种)。 相似文献
5.
R.B. Mabagala 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(2):175-181
Surface and internal populations of Xanthomonas campestris pv. phaseoli, causal agent of common bacterial blight of bean, on and in flower buds, blossoms and pods of seven bean (Phaseolus vulgaris) genotypes were studied. Bean plants were grown in the field and artificially inoculated at the seedling stage (18 days old). The pathogen was recovered in high numbers from flower buds, blossoms, pods and seed of both resistant and susceptible bean genotypes. Significant differences (P = 0.05) in population levels of X. c. pv. phaseoli between stages of reproductive tissue development were observed. Infected seed from resistant bean genotypes had no visible symptoms. Such seed may play an important role in the epidemiology of common bacterial blight because they are difficult to detect and may occur at low frequency in seed lots, as was the case in the current study. 相似文献
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甜菜源库关系的研究 总被引:6,自引:1,他引:5
为阐明源、库的关系对甜菜产量形成的影响。运用比较生理学的方法,研究了不同特性甜菜品种群体源、库的形成及其相互关系以及源、库发展在产量形成中的作用。结果表明,甜菜群体LAI和LAD可作为衡量源大小及能力的重要指标。光合源的同化能力直接影响着块根库容的大小,后期较大的光合源会抑制块根库的扩大,影响甜菜产量的形成。揭示了丰产、高糖甜菜品种的源库关系,LAI峰值出现在块根及糖分增长期,最大LAI应在4.3以上,达到峰值后要有20 d左右的相对稳定持续期,糖分积累后期LAI应保持在2.4左右。群体LAD应在块根及糖分增长期达到19.3 m2.d以上,后期呈缓慢下降变化。以上结果可为指导甜菜生产实践提高产量提供理论依据。 相似文献
8.
S. Mancuso F. Ferrini F. P. Nicese 《The Journal of Horticultural Science and Biotechnology》2013,88(6):777-784
SummaryThe potential use of the artificial neural networks (ANNs) for characterization and identification of seventeen chestnut (Castanea sativa Mill.) accessions, belonging to the ``marrone''-type and ``chestnut''-type, was investigated in genotypes originating from regions of Italy. Different back-propagation neural networks (BPNN) were built on the basis of image analysis parameters of the leaves, for two tasks of chestnut classification. In the first case a BPNN was built and trained to differentiate the 17 accessions of chestnut. In the second case a BPNN was conceived to distinguish between the ``marrone'' and ``chestnut'' types. BPNN produced a clear identification of all the accessions except in the case of `Garrone nero', `Garrone rosso' and `Tempuriva', which showed almost the same output diagram. Cluster analysis separated the 17 chestnut genotypes into four main groups whose differences were related to the original sources of the genotypes and to the type of affiliation (``marrone''-type or ``chestnut''-type). Artificial neural network technique was also able to discriminate between ``marrone''-type and ``chestnut''-type accessions. Qualitative and quantitative rules for the image analysis parameters, useful for classifying chestnut accessions into these two types, were obtained. On the whole the relative importance of the leaf parameters reveals that ``typical'' leaves for ``marrone''-type are more elongated, of a darker colour and with a higher perimeter/area ratio than the leaves of the ``chestnut''-type. 相似文献
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