Dissertation > Agricultural Sciences > Gardening > Ornamental Horticulture ( flowers and ornamental trees) > Perennial Flowers > Perennial Flowers Class > Chrysanthemum

Evaluation on Waterlogging Tolerance and Its Mechanisms in Chrysanthemum Morifolium and Its Related Species

Author YinDongMei
Tutor ChenFaZuo
School Nanjing Agricultural College
Course Ornamental Horticulture
Keywords Chrysanthemum Waterlogging stress Anaerobic respiration enzymes Antioxidant enzymes Aerenchyma Ethylene PCD
CLC S682.11
Type PhD thesis
Year 2011
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Chrysanthemum (Chrysanthemum morifolium) is a top ten famous flowers in China and the world one of the four major cut flowers, because of its high ornamental value and unique cultural connotation, widely used in the world within. The chrysanthemum is very sensitive to wet, water logging cultivate new varieties of chrysanthemum breeding has become an important target. Wild germplasm resources carry some cultivated species lack resistance gene, is an important foundation of resistance breeding material. Waterlogging Tolerance at 57 related species of Chrysanthemum species evaluated, discover the excellent flood-tolerant germplasm resources, explore chrysanthemum waterlogging tolerance physiological mechanism of biochemical and morphological anatomy, as well as ethylene under waterlogging stress root aerenchyma formation and ethanol fermentation system. Laid a foundation to promote the innovation of daisy Nailao germplasm and breeding of new varieties. The main findings are as follows: 1. Establishment of a closely related species of chrysanthemum flood-tolerant species seedling stage evaluation system. Daisy-related species based on the potted flooding process phenotypic changes in plants of the genus, waterlogging index is divided into seven; using leaf color, leaf shape, stem color, stem morphology 4 appearance indicators and quantitative grading develop Level score standards and evaluation program, then a comprehensive evaluation of the sum of each index score Waterlogging Tolerance to establish an evaluation system. And 57 closely related species of Chrysanthemum genus Waterlogging Tolerance at the seedling stage identification, of Waterlogging Tolerance identification time flooded six days is appropriate; daisy species closely related species are more sensitive to water logging, most of the material belongs less waterlogging tolerance level, with different provenance Waterlogging Tolerance differences; 8 Waterlogging Tolerance chrysanthemum excellent germplasm initial screening. Two closely related species of the five kinds of chrysanthemum is a plant root activity, chlorophyll content and photosynthetic physiological characteristics and waterlogging stress form of the performance of research and observation, preliminary evaluation compared the ability of waterlogging tolerance. The results show that: waterlogging stress, the root activity of five closely related species of Chrysanthemum genus sharp decline, but the purple flower Chrysanthemum exhibit strong root vigor early duress; five kinds of plant chlorophyll content first and then decreased overall trend; waterlogging stress the 15d when Kii-tidal daisy, bubble Huang Jinju photosynthetic intensity significantly reduced CO2 assimilation declined and turned negative, the leaves have lost the ability to photosynthesize, followed by Oshima wild road daisy and that HE Chuan Chrysanthemum, Medicago Chrysanthemum maintain a certain level of net photosynthetic rate. Waterlogging Tolerance significant difference in the two varieties of chrysanthemum as test materials, and study the impact of the apparent morphology and anaerobic respiration daisy enzyme, antioxidant enzyme activity and endogenous ethylene formation waterlogging stress. The results show that, Waterlogging Tolerance weak chrysanthemum varieties of '05 (13) -13 'serious waterlogging symptoms, stress four days that leaves wilting, chlorosis near the surface of the water leaves yellow and other symptoms waterlogging while Nailao strong '05 (53) -4 'no obvious symptoms of waterlogging stress within eight days, 20 days, flooding a large number of aerial roots at the stem appears, '05 (13) -13' is only a small number of aerial roots hyperplasia . Under waterlogging stress, and '05 (13) -13 'compared to to waterlogging tolerance varieties '05 (53) -4' roots anaerobic respiratory enzymes of ADH, LDH and PDC activity increase is not significant, leaf antioxidant enzymes SOD, CAT APX activity increase significantly. '05 (13)-13'MDA content increased significantly higher than '05 (53) 4 'the, two varieties stem base Endogenous ethylene levels have increased, but waterlogging tolerance varieties '05 (53) 4' the ethylene peak ratio '05 (13) -13 '2 days prior to appear, and the generation amount is '05 (13) -13', 3 times. That higher Department of antioxidant enzymes SOD, CAT, APX and lower anaerobic respiration activity of beneficial enhanced chrysanthemum plants of waterlogging, speculated that the differences of the two varieties of chrysanthemum stem base level of endogenous ethylene may adventitious root formation differences. Waterlogging Tolerance of Medicago Chrysanthemum (C. zawadskii) and waterlogging-sensitive daisy the Brain (C. nankingense) of the genus in the morphology and anatomy and physiological and biochemical indexes under waterlogging stress were observed and measured. The results indicate that the formation of the aerial roots hyperplasia and aerenchyma genus plant waterlogging tolerance mechanism. Waterlogging Tolerance Medicago indicum by morphological and anatomical changes in the structure, and actively adapt to hypoxia adversity, the main way of anaerobic respiration and ethanol fermentation, can maintain a high level of antioxidant enzyme activity and photosynthetic performance, chrysanthemum brain hypoxia Stress the main way of anaerobic respiration is lactic acid fermentation, 2 Waterlogging Tolerance differences. The exogenous ethylene plant roots aerenchyma formation and regulation of ethanol fermentation participating genus: and ethylene promote aerenchyma formation through the regulation of root PCD to avoid hypoxia adversity, to reduce the accumulation of fermentation metabolites, thereby enhancing the chrysanthemum genus waterlogging.

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