【作者】 田彦彦；

【导师】 杨秋生； 李永华；

【作者基本信息】 河南农业大学 ， 园林植物与观赏园艺， 2009， 硕士

【摘要】 本试验以秋菊晚花品种‘祥云’和早花品种‘唐宇金秋’为试材,对干旱及低温胁迫下菊花叶片的一系列生理指标和光合特性进行了测定,通过对不同菊花品种逆境胁迫下一些生理指标和光合指标与菊花抗逆性之间的关系的研究,探索菊花的抗性机理,并通过外源物质水杨酸的施用,研究水杨酸改善菊花抗寒性的作用机制,为菊花抗寒性研究提供理论基础和实践依据。研究表明:(1)干旱胁迫试验中,由对照到重度干旱,‘祥云’和‘唐宇金秋’叶片含水量分别下降了18.35%、15.81%,差异极显著,无论是下降幅度还是速度‘唐宇金秋’都小于‘祥云’,说明‘唐宇金秋’的抗旱保水能力强于‘祥云’。干旱胁迫造成‘祥云’和‘唐宇金秋’叶片中叶绿素含量的显著下降,重度胁迫后,‘唐宇金秋’叶绿素含量是‘祥云’的3.05倍,较高的叶绿素含量保证了‘唐宇金秋’具有较高的光合作用,从而减小了干旱胁迫对‘唐宇金秋’的影响。(2)干旱胁迫试验中,由对照到重度干旱,‘祥云’和‘唐宇金秋’叶片相对电导率分别上升了23.53%、8.95%,说明干旱对‘祥云’的细胞膜的伤害程度远大于‘唐宇金秋’。丙二醛含量变化趋势与电导率相似,从对照到重度干旱,‘祥云’增加了84.86%,‘唐宇金秋’增加了55.34%。重度胁迫时,‘祥云’MDA含量比‘唐宇金秋’高18.65%,表明‘唐宇金秋’细胞质膜受伤害程度较小。(3)干旱胁迫时,‘祥云’和‘唐宇金秋’叶片可溶性糖含量分别上升了117%、55%,脯氨酸含量分别上升了120.40%、50.69%,说明在遭遇干旱胁迫时,‘祥云’和‘唐宇金秋’都是主要通过诱导可溶性糖和脯氨酸,提高植物体抵抗逆境的能力。(4)在干旱胁迫中,从对照到重度干旱,‘祥云’和‘唐宇金秋’SOD活性分别上升了62.88%和90.96%,POD活性分别上升了40.48%和52.77%,保护酶活性的上升有利于清除植物体内有害的自由基,减少膜脂过氧化,保护膜系统免受伤害。(5)干旱胁迫中,与对照相比,重度胁迫时‘祥云’和‘唐宇金秋’的光补偿点分别上升了201.87%和890.38%,光饱和点先升后降,气孔导度分别下降了23.12%和15.92%,蒸腾速率分别下降了11.82%和15.92%。在各胁迫程度下,‘唐宇金秋’都有较低的光补偿点和较高的光饱和点,说明其对环境的适应能力比较强。(6)低温对菊花叶绿素含量影响较大,-4℃时‘祥云’CK叶绿素含量下降了30.23%,差异极显著,-8℃时‘唐宇金秋’CK叶绿素含量与4℃相比下降了37.75%,差异极显著。在4℃、0℃、-4℃和-8℃条件下,‘唐宇金秋’SA叶片中叶绿素含量比‘唐宇金秋’CK分别高了40.4%、26.06%、32.88%和42.00%,差异都极显著,表明水杨酸可部分缓解叶绿素含量下降,提高‘唐宇金秋’抗寒性。(7)在低温胁迫试验中,-8℃时,‘祥云’CK电导率比‘祥云’SA高38.79%,‘唐宇金秋’CK电导率比‘唐宇金秋’SA高26.61%,达到显著水平,表明在较低温度胁迫下水杨酸可显著提高菊花抗寒性,而在其它温度水平下,‘祥云’和‘唐宇金秋’叶片相对电导率差异均不显著。低温胁迫试验中,‘祥云’CK、‘祥云’SA、‘唐宇金秋’CK和‘唐宇金秋’SA叶片中丙二醛含量变化趋势与电导率相似,‘唐宇金秋’细胞膜膜脂过氧化程度高于‘祥云’,水杨酸降低了‘祥云’和‘唐宇金秋’的膜脂过氧化程度,差异不显著。(8)低温试验中,4℃时,‘唐宇金秋’CK可溶性糖含量为‘祥云’CK的19.84%,‘唐宇金秋’SA可溶性糖含量为‘祥云’SA的36.84%,-8℃‘唐宇金秋’CK可溶性糖含量为‘祥云’CK的205.47%,‘唐宇金秋’SA可溶性糖含量为‘祥云’SA的150.54%,表明‘唐宇金秋’可溶性糖含量上升速度较快;-8℃时‘祥云’SA可溶性糖含量比‘祥云’CK高138.79%,‘唐宇金秋’SA可溶性糖含量比‘唐宇金秋’CK高58.56%,水杨酸能够增加细胞可溶性糖含量,提高植物抗寒性,‘祥云’的应用效果要优于‘唐宇金秋’。低温胁迫中,-8℃时‘祥云’SA脯氨酸含量为‘祥云’CK的1.55倍,‘唐宇金秋’SA脯氨酸含量为‘唐宇金秋’CK的1.76倍,差异都达到显著水平,表明水杨酸在低温,尤其是零下低温时对提高植物体内游离脯氨酸含量,提高植物抗寒性效果显著。(9)在低温胁迫试验中,‘祥云’SA叶片SOD活性随着温度的降低而升高,最大值是最小值的2.73倍,‘祥云’CK、‘唐宇金秋’CK与‘唐宇金秋’SA叶片SOD活性均在-4℃时达到最大值,然后下降;‘祥云’CK、‘祥云’SA、‘唐宇金秋’CK与‘唐宇金秋’SA叶片APX活性均呈先升后降的趋势,在-4℃与-8℃时,‘祥云’SA叶片APX活性分别比‘祥云’CK高137.01%和153.26%,‘唐宇金秋’SA叶片APX活性分别比‘唐宇金秋’CK高84.10%和100.23%,结果表明水杨酸在零下低温对菊花APX活性影响显著。(10)低温胁迫下,与4℃相比,-8℃时,‘祥云’CK、‘祥云’SA、‘唐宇金秋’CK和‘唐宇金秋’SA净光合速率分别下降了83.75%、37.13%、90.76%和85.33%,差异都达到了显著水平。4℃时,‘祥云’CK净光合速率仅比‘唐宇金秋’CK高0.33%,-8℃‘祥云’CK净光合速率比‘唐宇金秋’CK高76.47%,差异显著,这可能与晚花品种的特性有关。(11)不同菊花品种其抗逆性也不同,主要表现在叶绿素、电导率、丙二醛、可溶性糖、脯氨酸、各种酶活性及净光合速率等方面,‘唐宇金秋’有较强的抗旱性,而‘祥云’有较强的抗寒性,这可能与品种特性有关。水杨酸可从多方面缓解低温对菊花造成的影响,从而提高菊花的抗寒性。更多还原

【Abstract】 Take autumn Chrysanthemum early-flowering variety‘Tangyujinqiu’and late-flowering variety‘Xiangyun’as materials, this experiment determined a series of physiological indices and photosynthetic characteristics of the Chrysanthemum leaves under drought and low-temperature stress. By studying the relationship between physiological and photosynthesis indices and the resistance of different species of Chrysanthemum under adversity stress, this paper probed the resistance mechanism, what’s more, by applying allogenic material salicylic acid, the action mechanism of salicylic acid on improving Chrysanthemum’s cold resistance was studied, which are hoped to provide the theoretical and practical basis for the further research. Studies shows:(1) In drought stress tests, from contrast to severe drought, the RWC in leaves of‘Xiangyun’and‘Tangyujinqiu’decreased 18.35%、15.81% respectively, which was significant.‘Tangyujinqiu’was lower than‘Xiangyun’both in decline extent and speed, which showed that‘Tangyujinqiu’was better than‘Xiangyun’in drought resistance under drought stress.Chlorophyll content of‘Xiangyun’and‘Tangyujinqiu’is decreased significantly because of drought stress.‘Tangyujinqiu’was 3.05 times of‘Xiangyun’in Chlorophyll content under severe drought stress. High chlorophyll content in‘Tangyujinqiu’guaranteed the high photosynthesis, which could greatly reduce the drought stress influence.(2) Drought stress tests showed: from contrast to severe drought, the relative conductivity of‘Xiangyun’and‘Tangyujinqiu’raised 23.53%、8.95% respectively, which showed that the cell membrane of‘Xiangyun’was hurt more seriously than that of‘Tangyujinqiu’.The change of MDA content was similar to that of the relative conductivity. From contrast to severe drought, the MDA content of‘Xiangyun’and‘Tangyujinqiu’raised 84.86% and 55.34% respectively. Under severe drought stress, the MDA content in‘Xiangyun’was 18.65% higher than in‘Tangyujinqiu’, which showed the cytomembrane of‘Tangyujinqiu’was hurt in a less degree.(3) Under drought stress, the soluble sugar content in leaves of‘Xiangyun’and‘Tangyujinqiu’raised by 117%、55%; the proline content raised by 120.40%、50.69% respectively. It indicated that‘Xiangyun’and‘Tangyujinqiu’could improve their resistances by inducing soluble sugar and praline.(4) From contrast to the severe drought, the activities of SOD of‘Xiangyun’and‘Tangyujinqiu’increased 62.88% and 90.96% respectively, the activities of POD of‘Xiangyun’and‘Tangyujinqiu’increased 40.48% and 52.77% respectively under drought stress. Protective enzyme could help clear up the harmful free radicals in plant body, reduce membrane lipid peroxidation and protect cell membrane system.Under different stress degree, both light compensation point and light saturation point of‘Tangyujinqiu’were quite high, which proved its strong adaptive capacity.(5) In drought stress test, compared with the contrast, LCP of‘Xiangyun’and‘Tangyujinqiu’increased 201.87% and 890.38% respectively; LSP firstly increased and then decreased; Gs decreased 23.12% and 15.92%,Tr decreased 11.82% and 15.92% under severe drought stress.(6) Low temperature led to the declination of chlorophyll content in Chrysanthemum leaves. The chlorophyll content in‘Xiangyun’CK declined 30.23% at the temperature of -4℃, and in‘Tangyujinqiu’CK declined by 37.75% at the temperature of -8℃comparing with that at 4℃. The chlorophyll content of‘Tangyujinqiu’SA was higher than that of‘Tangyujinqiu’CK by 40.4%、26.06%、32.88% and 42.00% respectively. The differences were extremely significant, which showed that salicylic acid could relieve the decline of chlorophyll content and enhance the cold resistance of Chrysanthemum.(7) In low-temperature tests, the relative conductivity of‘Xiangyun’CK was 38.79% higher than that of‘Xiangyun’SA, and in‘Tangyujinqiu’CK it was 26.61% higher than in‘Tangyujinqiu’SA at the temperature of -8℃. It’s indicated that salicylic acid can significantly improve the Chrysanthemum cold resistance. But the difference in the relative conductivity was not significant under other low temperatures. Test showed: under low temperatures, the change of MDA content in‘Xiangyun’and‘Tangyujinqiu’was similar to that of the relative conductivity, while the level of epicyte membrane liquid peroxidation in‘Tangyujinqiu’was higher than in‘Xiangyun’. Salicylic acid reduces the membrane liquid peroxidation level, and the differences were not significant.(8) Low temperature test showed: at the temperature of 4℃, the soluble sugar content in leaves of‘Tangyujinqiu’CK was 19.84% that of‘Xiangyun’CK, and the soluble sugar content of‘Tangyujinqiu’SA is 36.84% that of‘Xiangyun’SA; at -8℃, the soluble sugar content of‘Tangyujinqiu’CK is 205.47% that of‘Xiangyun’CK, and the soluble sugar content of‘Tangyujinqiu’SA is 150.54% that of‘Xiangyun’SA, which showed that the soluble sugar content of‘Tangyujinqiu’raised faster. The soluble sugar content of‘Xiangyun’SA is 138.79% higher than that of‘Xiangyun’CK, and the soluble sugar content of‘Tangyujinqiu’SA is 58.56% higher than that of‘Tangyujinqiu’CK. Salicylic acid could increase the soluble sugar content and improve cold resistance greatly, and the effect was more obviously in‘Xiangyun’. Under low temperature stress, the proline content of‘Xiangyun’SA is 55% higher than that of‘Xiangyun’CK, and the proline content of‘Tangyujinqiu’SA was 76% higher than that of‘Tangyujinqiu’CK. The differences were significant, which showed that salicylic acid could improve their cold resistance significantly by increasing the free proline content under low temperature, especially in negative temperature.(9) In low temperature test, the activity of SOD in‘Xiangyun’SA increased as temperature fell, and the maximum was 2.73 times the minimum; the activities of SOD in‘Xiangyun’CK,‘Tangyujinqiu’CK and‘Tangyujinqiu’SA reached the maximum at 4℃, and then dropped down; the activitis of APX in‘Xiangyun’CK,‘Xiangyun’SA,‘Tangyujinqiu’CK and‘Tangyujinqiu’SA increasd firstly and then decreased. At -4℃and -8℃, the activities of APX in‘Xiangyun’SA was 137.01% and 153.26%, higher than that in‘Xiangyun’CK; the activities of APX of‘Tangyujinqiu’SA was 84.10% and 100.23%, higher than that in‘Tangyujinqiu’CK, which showed that salicylic acid could noticeably impact the activity of APX at negative temperature.(10) In low temperature test, comparing with 4℃, Pn of‘Xiangyun’CK,‘Xiangyun’SA,‘Tangyujinqiu’CK and‘Tangyujinqiu’SA fell 83.75%, 37.13%, 90.76% and 85.33% respectively,the differences were significant. Pn of‘Xiangyun’CK was only 0.33% higher than that of‘Tangyujinqiu’CK at 4℃, and‘Xiangyun’CK was 76.47% higher than that of‘Tangyujinqiu’CK at -8℃, the difference is significant, which may be related to the characteristics of late-flowering.(11) The resistances of different Chrysanthemum varieties were different, which are mainly shown in the chlorophyll, conductivity, MDA, soluble sugar, proline, all sorts of enzyme activities and the net photosynthetic rate, etc.‘Tangyujinqiu’presented stronger drought resistance, and‘Xiangyun’presented stronger cold resistance, which may be related to the variety characteristics. Salicylic acid could alleviate the impact of low temperature on Chrysanthemum and enhance its cold resistance.更多还原