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951.
不同颜色果袋对李果实着色及花色素苷合成的影响因素分析 总被引:2,自引:2,他引:2
以大石早生李为试材,研究了不同颜色的果袋对李(Prunus salicina Lindl.)果实外观色泽、花色素苷含量的影响,并探讨了果实中糖酸含量、PAL(苯丙氨酸氨解酶)和UFGT(类黄酮葡糖苷转移酶)酶活性与花色素苷合成的关系。结果表明,果袋的透光率与果皮外观色泽有密切关系,透光率越高,a*越大,果皮颜色越红。白色果袋与对照、红袋与黄袋果实外观无显著差异,白袋与红袋,黑袋(完全不透光)与黄袋,红袋与黄袋处理之间的果实外观色泽存在显著差异。果实成熟时果皮中花色素苷含量与纸袋的透光率呈正比,波长580nm以上橙、红光的透光率与果皮中花色素苷含量相关系数r>0.99。在不同颜色果袋影响果实成熟时果皮的糖酸积累方面:不同颜色果袋对果肉中糖酸含量无显著影响,果皮的糖含量与花色素苷含量亦无显著相关性,但成熟时果皮中酸含量与花色素苷含量呈显著正相关(r=0.9815*)。不同颜色果袋影响PAL、UFGT酶活性,果实成熟时不同果袋PAL酶活性与花色素苷含量相关性显著(r=0.9613*),UFGT酶活性与花色素苷含量相关性显著(r=0.9365*)。 相似文献
952.
施钙对桃品质和贮藏性能的影响 总被引:8,自引:0,他引:8
桃属于呼吸跃变型果实,采前钙处理能够提高桃果实内结合态钙的含量。增补果实钙含量的方法,一般有根部施肥、叶面喷施、采后浸果与采前调节树体钙分配等4种。钙肥施用中应特别注意施用时期与位置的针对性,使钙能直接补充到幼果期的果实。据肖颖等报道对桃树进行低浓度钙处理,桃果实的可溶性固形物含量高于对照(未进行钙处理)的树。徐凌等研究表明,采前桃树使用硝酸钙与赤霉素喷布,可增进桃果实的贮藏品质。杜建厂等报道采前喷钙可提高采后果实的钙及可溶性固形物的含量,增强果实耐贮性。肖红梅等的研究表明钙处理不仅能显著提高贮藏期的好果率,而且能抑制货架期果实的发霉,延长桃的货架期。对于几种钙肥的比较未见有报道,本试验以早熟油桃为试材,调查3种常用钙肥土施效果,以期为生产上应用钙肥提供参考。 相似文献
953.
20世纪90年代以来,广西桂林、柳州、贺州等地一些桔园的温州蜜柑和沙田柚出现了一种春梢叶片扭曲畸形、植株矮化的病害——温州蜜柑矮化病和柚矮化病,近年更有逐年加重的趋势。现已有实验证明,该两病均由茎陷点型衰退病毒引起。而近年广西一些桔园出现的纽荷尔脐橙果实变圆、变扁,个头变小,有时果顶部出现放射状沟,枝条木质部产生严重茎陷点的症状,也是由茎陷点型衰退病毒引起。《柑桔衰退病》一文简明扼要地介绍了柑桔衰退病的“症状、寄主范围、病原、流行病学、诊断检测及防控策略”,对于读者认识和治理温州蜜柑矮化病和柚矮化病可能会有所帮助。因此翻译出来,以供参考。 相似文献
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ABSTRACT The pathogens causing perennial canker of peach, Leucostoma spp., were characterized in Michigan orchards to identify which species and subgroups (cryptic species) were prevalent on a highly susceptible peach cultivar, Loring, and a less susceptible cultivar, Redhaven. Four hundred and three strains of Leucostoma were isolated from cankers in three southwest Michigan orchards where 'Loring' occurred adjacent to 'Redhaven' in side-by-side plots. Based on colony morphology and small nuclear rDNA size polymorphisms, three cryptic species were detected; 89% of the isolates were identified as L. persoonii phenetic group 1, 10% were L. cincta group 4, and 1% were L. persoonii group 2. Pathogen profiles differed significantly between cankers on small branches of 'Loring' and 'Redhaven', and between cankers on small branches and trunks. Of 1,232 random pairings among isolates of L. persoonii group 1, 95% were vegetatively incompatible. A minimum of 11 and a maximum of 17 maternal lines were identified based upon mitochondrial DNA restriction fragment length polymorphisms among 69 isolates of L. persoonii group 1 from one split-cultivar block of 72 trees. Vegetative compatibility loci were randomly associated with maternal lines. Evidence of clonality was absent in L. persoonii group 1, as no correlation occurred between these two sets of independent genetic markers and no genotype was over-represented. The number of cryptic species, the number of maternal lines, and the frequency of incompatibility within maternal lines indicate that considerable genetic variation exists within the Leucostoma populations in Michigan peach orchards, and that sexual recombination is common. 相似文献
959.
ABSTRACT During gel (gum) formation in angiosperm trees, fibrillar material accumulated in protective layers of xylem parenchyma cells before being secreted across half-bordered pit membranes into vessel elements. Immunogold labeling demonstrated that this fibrillar material was mainly composed of partially esterified pectic polysaccharides. The primary wall of expanding tyloses, an extension of the parenchyma protective layer, secreted similar pectic substances to completely block vessel elements. In most studies, these occluding structures were reported to be formed in response to causative factors such as aging processes, injuries, or infections. Current observations support the view that partial to complete embolism, which almost always accompanies these factors, might be the main cause triggering the formation of vessel occlusions. Whereas pectin seems to be the basic component of gels (gums) and of the external layer of tyloses, other substances, such as phenols, were also detected either as a part of these plugs or as accumulations beside them in vessels. Finally, it is proposed that the term 'gel' instead of 'gum' be used in future studies to describe the occluding material secreted by ray and paratracheal parenchyma cells. 相似文献
960.
rep-PCR-Mediated Genomic Fingerprinting: A Rapid and Effective Method to Identify Clavibacter michiganensis 总被引:1,自引:0,他引:1
Louws FJ Bell J Medina-Mora CM Smart CD Opgenorth D Ishimaru CA Hausbeck MK de Bruijn FJ Fulbright DW 《Phytopathology》1998,88(8):862-868
ABSTRACT The genomic DNA fingerprinting technique known as repetitive-sequence-based polymerase chain reaction (rep-PCR) was evaluated as a tool to differentiate subspecies of Clavibacter michiganensis, with special emphasis on C. michiganensis subsp. michiganensis, the pathogen responsible for bacterial canker of tomato. DNA primers (REP, ERIC, and BOX), corresponding to conserved repetitive element motifs in the genomes of diverse bacterial species, were used to generate genomic fingerprints of C. michiganensis subsp. michiganensis, C. michiganensis subsp. sepedonicus, C. michiganensis subsp. nebraskensis, C. michiganensis subsp. tessellarius, and C. michiganensis subsp. insidiosum. The rep-PCR-generated patterns of DNA fragments observed after agarose gel electrophoresis support the current division of C. michiganensis into five subspecies. In addition, the rep-PCR fingerprints identified at least four types (A, B, C, and D) within C. michiganensis subsp. michiganensis based on limited DNA polymorphisms; the ability to differentiate individual strains may be of potential use in studies on the epidemiology and host-pathogen interactions of this organism. In addition, we have recovered from diseased tomato plants a relatively large number of naturally occurring avirulent C. michiganensis subsp. michiganensis strains with rep-PCR fingerprints identical to those of virulent C. michiganensis subsp. michiganensis strains. 相似文献