UV-B辐射下茉莉酸甲酯对铁皮石斛生长和主要活性成分的影响研究

发布时间：2018-03-09 08:04

本文选题：铁皮石斛　切入点：UV-B辐射　出处：《广东药科大学》2017年硕士论文　论文类型：学位论文

【摘要】：本课题组前期研究发现,UV-B辐射能影响铁皮石斛苗的生长和活性成分的含量。茉莉酸甲酯是植物受到外界刺激时反应最迅速的信号分子,参与植物生长发育的各个过程以提高植物对逆境的适应性。本论文探讨了UV-B辐射下茉莉酸甲酯对铁皮石斛生长和主要活性成分的影响,实验方案及结果如下:本实验以铁皮石斛组培苗为研究对象,在能造成铁皮石斛苗伤害的UV-B辐射剂量下(15.6μW·cm-2)下,以MS为培养基,外源添加浓度为5mmol/L的茉莉酸甲酯,然后分别进行持续3、6、9、12小时的UV-B照射。考察铁皮石斛苗的光合色素含量、抗氧化酶活性以及主要活性成分的变化,然后选择该浓度茉莉酸甲酯能缓解UV-B辐射伤害及提高其活性成分含量的合适时间,进行8天周期性UV-B辐射实验。考察不同浓度的茉莉酸甲酯对铁皮石斛周期性UV-B辐照的响应。各实验处理中,喷施不同浓度的茉莉酸甲酯后,立即进行每天6小时的UV-B照射,茉莉酸甲酯浓度分别为:0 mmol/L(简称UV-B)、1 mmol/L(简称UV-B+MeJA1,下同)、2.5 mmol/L(UV-B+MeJA2.5)、5 mmol/L(UV-B+MeJA5)、7.5 mmol/L(UV-B+MeJA7.5)、10 mmol/L(UV-B+MeJA10)。在实验的第2、4、6、8天,分别通过考察铁皮石斛苗的萌蘖数、叶片破坏率、光合色素含量、抗氧化酶活性以及主要活性成分的变化,以研究茉莉酸甲酯对铁皮石斛周期性UV-B辐射的响应持续时间和浓度。在此基础上,探讨UV-B辐射下,茉莉酸甲酯对两个抗逆性存在明显差异的铁皮石斛品种的影响是否存在差异。主要结果如下:(1)短时间UV-B辐射下茉莉酸甲酯对铁皮石斛的影响在UV-B持续照射下,铁皮石斛苗的光合色素含量减少,而添加茉莉酸甲酯能提高光合色素的含量。UV-B+MeJA组的POD、CAT含量明显高于CK和UV-B组,其含量分别较CK增加40%、55%、55%,且丙二醛含量较CK低,总多糖的含量较CK和UV-B组显著增加(P0.05)。在实验处理3、6、9、12小时后其含量较CK增加568%、307%、47%、38%。随着时间的延长,而UV-B+MeJA组总黄酮含量在3小时含量较CK低,在6小时后含量逐渐增加。在实验处理6小时后,UV-B+MeJA叶绿素a含量较CK显著增加(P0.05),含量较CK增加38.2%。同时铁皮石斛苗叶绿素b、类胡萝卜素含量逐渐增加。(2)周期性UV-B照射下茉莉酸甲酯对铁皮石斛的影响UV-B照射下,不同浓度的茉莉酸甲酯对铁皮石斛苗叶片的影响程度不一样。随着茉莉酸甲酯浓度的提高,对UV-B辐射造成的叶片破坏缓解能力降低。在照射的第8天,不同浓度茉莉酸甲酯,对叶片的破坏率分别是100%、87.9%、51%、84.4%、83%、100%。其中UV-B+MeJA5组的叶片破坏率最小。此外,UV-B+MeJA1、UV-B+MeJA2.5、UV-B+MeJA5、UV-B+MeJA7.5和UV-B+MeJA10组萌蘖数前期增加,但在后期萌蘖受阻;而UV-B+MeJA2.5和UV-B+MeJA5组的萌蘖数在呈缓慢上升的趋势。在实验处理的前6天,铁皮石斛苗光合色素含量增加较多;在实验处理的6天后铁皮石斛苗光合色素含量降低。同时,不同浓度的茉莉酸甲酯对铁皮石斛苗的光合色素含量影响不同,UV-B+MeJA5和UV-B+MeJA7.5组光合色素含量始终高于UV-B、UV-B+MeJA1、UV-B+MeJA2.5和UV-B+MeJA10组。UV-B+MeJA5和UV-B+MeJA7.5组中的抗氧化酶活性较UV-B显著增加(P0.05)。此外,UV-B+MeJA1、UV-B+MeJA2.5和UV-B+MeJA5的MDA含量均较UV-B低,UV-B+MeJA7.5和UV-B+MeJA10处理组的MDA含量较高。可见低浓度的茉莉酸甲酯在一定程度上可以减轻UV-B辐射对膜脂过氧化产生的伤害。对铁皮石斛主要活性成分的影响:在实验处理的第4天,UV-B+MeJA5和UV-B+MeJA7.5组总多糖含量大于UV-B组(P0.05),其含量分别为UV-B组的108%和105%。此外,在实验处理的第2、4、6天时,UV-B+MeJA2.5的总黄酮含量分别为UV-B组的86%、106%、41%。在实验处理第2天时,UV-B+MeJA5处理中总黄酮影响不显著(P0.05),在实验处理第2、6天总黄酮含量分别为UV-B的100%和40%。(3)UV-B辐射下,两个铁皮石斛品种对外源茉莉酸甲酯的响应两个品种的铁皮石斛苗在UV-B照射下用茉莉酸甲酯处理,光合色素含量增加。铁皮石斛YQ-2品种的光合色素含量、抗氧化酶活性较YH-1品种铁皮石斛增加较大。YH-1和YQ-2多糖含量变化不显著,而YH-1品种黄酮含量较YQ-2高。综上所述,在UV-B照射下,不同浓度的茉莉酸甲酯在不同的时间内,对铁皮石斛苗生长和主要活性成分的作用不一样。高浓度的茉莉酸甲酯不利于铁皮石斛苗的生长,而且使得铁皮石斛的活性成分减少;茉莉酸甲酯的浓度适当降低,如UV-B+MeJA5,铁皮石斛的多糖和黄酮含量较UV-B显著提高,且有利于缓解UV-B辐射对铁皮石斛苗生长的伤害作用;茉莉酸甲酯浓度过低,如UV-B+MeJA2.5,铁皮石斛苗的多糖和黄酮含量则增加,但铁皮石斛苗的生长受阻。因此当茉莉酸甲酯浓度为5 mmol/L(UV-B+MeJA5)时可以减轻UV-B照射对铁皮石斛苗的伤害作用,并提高铁皮石斛的总多糖和黄酮含量。同时研究发现茉莉酸甲酯对抗UV-B辐射存在时间效应。在6天内添加茉莉酸甲酯能通过提高铁皮石斛苗的光合色素含量、保护酶活性、主要活性成分,缓解UV-B辐射的伤害。在照射6天后,铁皮石斛光合色素含量、保护酶活性、主要活性产物均降低。本实验发现对于抗逆性不同的铁皮石斛品种,其对光合色素含量、保护酶的影响不同。抗逆性越强的保护酶活性上升幅度越大,且膜脂过氧化程度较低。
[Abstract]:Our previous studies showed that UV-B radiation can affect the content of seedling growth of Dendrobium candidum and active ingredients. Methyl jasmonate in plants is stimulated by the outside signal molecules when the most rapid response, are involved in the process of plant growth and development in order to improve the adaptability of plants to stress. This paper discusses the UV-B radiation effects of Methyl Jasmonate on the growth of Dendrobium candidum and the main active ingredient, the experimental scheme and results are as follows: in this experiment, the plantlet of Dendrobium officinale as the research object, the radiation dose can cause UV-B damage of Dendrobium seedlings under (15.6 W cm-2), in MS medium, concentration of exogenous methyl jasmonate 5mmol/L. Then, last 3,6,9,12 hours UV-B irradiation. The influences of Dendrobium seedlings photosynthetic pigment content, antioxidant enzyme activity changes as well as the main active ingredient, and then select the concentration of methyl jasmonate UV-B can alleviate the radiation injury and improve the content of the active components of the appropriate time for 8 days, the periodic UV-B radiation experiment. The response of different concentration of Methyl Jasmonate on Dendrobium periodic UV-B irradiation. The experimental treatment, different concentration of methyl jasmonate immediately after spraying, 6 hours a day UV-B irradiation the concentration of methyl jasmonate, respectively: 0 mmol/L (UV-B), 1 mmol/L (UV-B+MeJA1, the same below), 2.5 mmol/L (UV-B+MeJA2.5), 5 mmol/L (UV-B+MeJA5), 7.5 mmol/L (UV-B+MeJA7.5), 10 mmol/L (UV-B+MeJA10) in the experiment. The first 2,4,6,8 days, respectively by the number of Dendrobium seedlings sprouting on the damage rate, leaf, photosynthetic pigment content, antioxidant enzyme activity changes as well as the main active ingredient, the study of Methyl Jasmonate on Dendrobium periodic UV-B radiation response duration and concentration. On this basis, to explore the UV-B radiation, Effect of methyl jasmonate has obvious difference of two resistance of Dendrobium species difference. The main results are as follows: (1) a short time under UV-B radiation of Methyl Jasmonate on Dendrobium candidum effect in UV-B continuous irradiation, Dendrobium seedlings photosynthetic pigment content decreased, while the addition of methyl jasmonate can improve the photosynthetic pigment content of.UV-B+MeJA and POD in group CAT was significantly higher than that in CK and UV-B group, the content of CK were increased by 40%, 55%, 55%, and the content of MDA was lower than that of CK, the content of total polysaccharide group increased significantly compared with CK and UV-B (P0.05). In the experiment after 3,6,9,12 hours of treatment the content is CK increased by 568%, 307%, 47%, 38%. with the extension of time, while in UV-B+MeJA group, the content of total flavonoids in 3 hours were lower than those of the CK increased gradually in 6 hours after the content in the experiment. After 6 hours treatment of UV-B+MeJA compared with CK significantly increased the content of chlorophyll a (P0.05), CK content was increased by 38 At the same time.2%. Dendrobium seedlings chlorophyll b, carotenoid content increased gradually. (2) the periodic UV-B irradiation effects of Methyl Jasmonate on Dendrobium UV-B under the irradiation of different concentration of Methyl Jasmonate on Dendrobium Candidium seedlings are not the same. With the increase of the concentration of jasmonic acid methyl ester, to UV-B radiation the blade damage mitigation capability decreased. In eighth days after irradiation, different concentrations of methyl jasmonate, on leaf damage rate were 100%, 87.9%, 51%, 84.4%, 83%, 100%. in the leaves of group UV-B+MeJA5 damage rate is minimum. In addition, UV-B+, MeJA1, UV-B+MeJA2.5, UV-B+MeJA5, UV-B+MeJA7.5 and UV-B+MeJA10 group from the early increase in number but, in the late sprouting and sprouting of UV-B+MeJA2.5 and the number of blocked; group UV-B+MeJA5 increased slowly. In 6 days before the experimental treatment, Dendrobium seedlings photosynthetic pigment content increased; in the 6 Reduce the days of Dendrobium seedlings photosynthetic pigment content. At the same time, different concentration of Methyl Jasmonate on Dendrobium seedlings photosynthetic pigment content and the effect of different UV-B+MeJA5, UV-B+MeJA7.5 group of photosynthetic pigment content is always higher than that of UV-B, UV-B+MeJA1, UV-B+MeJA2.5 and UV-B+MeJA10.UV-B+ MeJA5 group and UV-B+MeJA7.5 group in the activity of antioxidant enzymes increased significantly (P0.05 compared with UV-B UV-B+MeJA1, MDA). In addition, the content of UV-B+MeJA2.5 and UV-B+MeJA5 were lower than UV-B, UV-B+MeJA7.5 and UV-B+MeJA10 group MDA. High content of methyl jasmonate indicated that low concentration can reduce the UV-B radiation on membrane lipid peroxidation caused damage to a certain extent. The effect of the main active ingredients of Dendrobium candidum: on the fourth day the UV-B+MeJA5 and UV-B+MeJA7.5 group, the total polysaccharide content was higher than that of group UV-B (P0.05), the contents were 108% in group UV-B and 105%. in addition, in the experimental treatment No. 2,4,6 days, the total flavone content of UV-B+MeJA2.5 UV-B group was 86%, 106%, 41%. in the second day, the total flavonoids in the effect of UV-B+MeJA5 treatment was not significant (P0.05), in the first 2,6 days of total flavonoids were 100% for UV-B and 40%. (3) UV-B radiation, two varieties the Dendrobium seedlings under UV-B irradiation with methyl jasmonate response of two Dendrobium species of Exogenous Methyl jasmonate, photosynthetic pigment content increased. Dendrobium YQ-2 variety of photosynthetic pigment content, antioxidant enzyme activity than YH-1 species of Dendrobium officinale increased.YH-1 and YQ-2 change of polysaccharide content was not significant, and the YH-1 content of flavonoids varieties was higher than that of YQ-2. In conclusion, after UV-B irradiation, different concentrations of methyl jasmonate in different time on d.candidum seedling growth and the main active components of the role is not the same. The high concentration of methyl jasmonate to iron Dendrobium seedlings growth, and the active components of Dendrobium decreased; concentration of MeJA reduced, such as UV-B+MeJA5, polysaccharides and flavonoids content of Dendrobium candidum significantly increased compared with UV-B and UV-B, will help alleviate the radiation damage effect on the growth of Dendrobium seedlings; the concentration of methyl jasmonate is too low, such as UV-B+MeJA2.5, multi sugar and flavonoid content of Dendrobium seedlings increased, but the growth of Dendrobium seedlings blocked. So when MeJA concentration was 5 mmol/L (UV-B+MeJA5) can reduce harmful effects of UV-B irradiation on Dendrobium seedlings, and improve the Dendrobium polysaccharide and flavonoids contents. The study also found that methyl jasmonate against UV-B radiation has time effect. The addition of MeJA in 6 days can improve Dendrobium seedlings photosynthetic pigment content, protective enzyme activity, the main active ingredient, alleviate the radiation damage in UV-B. According to 6 days after the shooting, Dendrobium photosynthetic pigment content, protective enzyme activity, the main active products were decreased. The study found that for different resistance of Dendrobium varieties, the photosynthetic pigment content, protective enzyme activity of protective enzymes. The effects of different resistance stronger increase amplitude was bigger, and the membrane lipid peroxidation was low.

【学位授予单位】：广东药科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S567.239

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