【作者】 张益锋；

【导师】 何平；

【作者基本信息】 西南大学 ， 植物学， 2010， 博士

【摘要】 全球干旱、半干旱地区约占耕地面积的一半,这些地区水分供应不足,森林植被疏稀,生态环境恶化,水土流失严重,自然灾害频繁。而全球气候变化与局部干旱化将导致越来越多的干旱、半干旱地区受到更为严重的干旱胁迫影响。干旱胁迫对植物的影响是多方面的,其中就包括生物量积累和分配、光合色素、保护物质和保护酶系统。平流层臭氧层的衰减会直接导致到达地表的UV-B辐射(280-315 nm)的增强,对植物的生长发育造成不可避免的影响。因此,增强UV-B辐射势必会影响到植物对干旱胁迫的响应或敏感性。金荞麦(Fagopyrum dibotrys (D.Don) Hara)不但是国家Ⅱ级重点保护野生植物,且在药理和临床方面都具有较高的药用价值,由于其药用价值,金荞麦需求量与日俱增。而荞麦(Fagopyrum esculentum Moench.)是一种我国广泛栽培的且具有很高营养价值的作物。本文研究了模拟增强UV-B辐射及干旱胁迫下的金荞麦和荞麦生物量积累与分配、叶光合色素、叶保护物质和保护酶的响应,比较了两种荞麦属植物在上述条件下的可塑性差异,以此探讨增强UV-B辐射对处于干早胁迫下的植物影响,以期为金荞麦的保护利用和荞麦的种植提供理论依据。1)干旱胁迫导致了金荞麦和荞麦各营养器官生物量和总生物量积累降低,且随着干旱胁迫程度的加深,这种降低的趋势越明显。荞麦根生物量配置随干旱胁迫的加重显著升高,金荞麦则无明显规律。金荞麦和荞麦茎生物配配置和叶生物量配置有随着干早胁迫程度加深而下降的趋势。大充足水分状况下：增强UV-B辐射显著降低了金荞麦和荞麦根生物量、叶生物量和总生物量积累：增强的UV-B辐射同样降低了金荞麦茎生物量积累,而荞麦茎生物量积累对增强的UV-B辐射却不敏感：增强UV-B辐射还使荞麦花序生物量积累提高了；增强的UV-B辐射降低了金荞麦根生物量配置,而荞麦根生物量配置对增强的UV-B辐射并不敏感；增强的UV-B辐射能提高金荞麦和荞麦茎生物量配置；金荞麦叶生物量配置对增强的UV-B辐射不敏感,而增强UV-B辐射降低了荞麦叶生物量配置；增强的UV-B辐射能提高荞麦花序生物量配置。在中度干旱胁迫下：增强的UV-B辐射提高了金荞麦和荞麦根生物量积累；增强的UV-B辐射能使金荞麦和荞麦茎生物量积累得到提高,但这种影响只在特定的处理时间点上达到显著水平；增强的UV-B辐射能使得金荞麦叶生物量积累先降低后升高,却增加了荞麦叶生物量积累；增强UV-B辐射使荞麦花序生物量积累升高；增强UV-B辐射能提高金荞麦根生物量配置,却降低了荞麦根生物量配置；金荞麦和荞麦茎生物量配置对增强UV-B辐射不敏感；金荞麦叶生物量配置对增强的UV-B辐射不敏感,而增强UV-B辐射大特定时期能提高荞麦叶生物量配置：荞麦花序生物量配置对增强的UV-B辐射不敏感。在重度干旱胁迫下：增强的UV-B辐射也提高了金荞麦和荞麦根生物量积累；增强的UV-B辐射能使金荞麦和荞麦茎生物量积累得到一定提高,但这种影响只在特定的处理时间点上达到显著水平；金荞麦叶生物量对增强的UV-B辐射并不敏感,增强的UV-B辐射却显著增强了荞麦叶生物量积累；增强的UV-B辐射使荞麦花序生物量积累升高了；金荞麦根生物量配置对增强UV-B辐射不敏感,增强的UV-B辐射却提高了荞麦根生物量配置；增强UV-B辐射对金荞麦和荞麦茎生物量配置无显著影响；金荞麦叶生物量配置对增强UV-B的辐射不敏感,而增强UV-B辐射显著提高了荞麦叶生物量配置；增强的UV-B辐射降低了荞麦花序生物量配置。从生物量综合特征可塑性指数来看,UV-B辐射或干旱处理中金荞麦生物量综合特征可塑性比荞麦要高,金荞麦在生物量综合特征方面表现出比荞麦更高的可塑性。2)金荞麦和荞麦叶叶绿素a含量、叶绿素b含量和总叶绿素含量都随干旱程度的加重而降低：在充足水分状况下,增强的UV-B辐射降低了金荞麦和荞麦叶绿素a含量、叶绿素b含量和总叶绿素含量；而在干旱胁迫下,除金荞麦叶绿素a含量对增强的UV-B辐射不敏感外,增强的UV-B辐射都能提高荞麦叶绿素a含量、金荞麦和荞麦叶绿素b含量和总叶绿素含量。金荞麦叶绿素a/叶绿素b随干旱胁迫程度的加重而降低,在处理中期最为明显：中度干旱胁迫在处理中期提高了荞麦叶绿素a/叶绿素b；无论是充足水分还是干旱胁迫条件下,叶绿素a/叶绿素b比值对增强的UV-B辐射都不敏感。金荞麦和荞麦叶类胡萝卜素含量都随干早胁迫加重而降低；只有在充足水分状况下,增强的UV-B辐射提高了金荞麦叶类胡萝卜素含量,而其它水分状况下,金荞麦和荞麦叶胡萝卜素含量对增强的UV-B辐射不甚敏感。金荞麦和荞麦类胡萝卜素/叶绿素比值在处理中后期基本有随干旱程度的加深而升高的趋势,到后期达到显著水平；在充足水分状况下,增强的UV-B辐射显著提高了金荞麦类胡萝卜素／叶绿素比值,而其它水分状况下,金荞麦和荞麦类胡萝卜素／叶绿素比值对增强的UV-B辐射不甚敏感。从光合色素可塑性指数来看,UV-B辐射或干旱处理中金荞麦光合色素可塑性比荞麦要高,金荞麦在光合色素方面表现出比荞麦更高的可塑性。3)金荞麦和荞麦SOD活性、总黄酮含量、丙二醛含量和可溶性糖含量随干早胁迫的增加而显著上升；POD活性随干旱胁迫的加深而升高,在处理中期达到显著水平,而在处理前期和后期,这种影响似乎有减弱的趋势；在处理前中期游离脯氨酸含量随干旱胁迫的加重而上升,在处理后期则无明显规律；金荞麦可溶性蛋白含量在处理前期随干旱胁迫的加深而升高,而到处理中后期则随干旱胁迫的加深而降低,荞麦可溶性蛋白含量在处理前期随干旱程度的加深而增高,而在处理后期则刚好相反。在充足水分状况下,增强的UV-B辐射处理提高了金荞麦和荞麦叶SOD活性、总黄酮含量、游离脯氨酸含量、丙二醛含量；增强的UV-B辐射在处理前期和后期提高了金荞麦POD活性,荞麦则不同,增强的UV-B辐射在处理后期降低了其POD活性；增强的UV-B辐射在处理前期增加了金荞麦叶可溶性蛋白含量,而在后期则减小了金荞麦和荞麦叶可溶性蛋白含量；增强的UV-B辐射降低了金荞麦和荞麦叶可溶性糖含量。在干早胁迫下,增强的UV-B辐射在处理中期提高了金荞麦SOD活性,而在处理前期和后期却降低了其SOD活性；增强的UV-B辐射在处理后期升高了金荞麦叶P.OD活性,却降低了荞麦叶POD活性；增强的UV-B辐射在处理后期降低了荞麦叶总黄酮含量；增强的UV-B辐射提高了金荞麦叶游离脯氨酸含量,在处理中期降低了荞麦叶游离脯氨酸含量；增强的UV-B辐射提高了金荞麦和荞麦叶丙二醛含量；在中度干旱胁迫下,增强的UV-B辐射提高了金荞麦叶可溶性蛋白含量,而在重度干旱胁迫下,增强的UV-B辐射在处理前中期提高了金荞麦叶可溶性蛋白含量,而在后期则减小了其叶可溶性蛋白含量,而荞麦叶可溶性蛋白含量始终对增强的UV-B辐射不敏感；增强的UV-B辐射显著降低了金荞麦叶可溶性糖含量,而荞麦只在重度干旱胁迫下才有这种影响。在UV-B辐射和干旱处理下,金荞麦在保护酶和保护物质方面表现出比荞麦更高的可塑性。总之,在干旱条件下增强的UV-B辐射不会加剧对金荞麦和荞麦的伤害,而在一定程度上有利于提高两者对干旱的抗性。更多还原

【Abstract】 The world’s arid and semi-arid regions account for about half of the arable land. In these areas, there is a shortage of water supply, sparse vegetation and sparse forest, ecological environment deterioratiosn, serious soil erosion, and frequent natural disasters. With global climate changes and local drought, more arid and semi-arid areas will be more seriously affected by drought stress. The influences of drought stress on plants are manifold, including biomass accumulation and allocation, photosynthetic pigments, protective substance and protective enzymes changes. The attenuation of the stratospheric ozone layer will directly lead in the enhancement of UV-B radiation (280-315 nm) onto the earth surface. This will inevitably affect the growth and development of the plants. Therefore, the enhanced UV-B radiation is bound to affect the response or sensitivity of plants toward drought stress.Fagopyrum dibotrys (D.Don) Hara is not only a kind of the national key protected wild plants of gradell, but also a plant with high pharmacological and clinical value. For its medicinal value, there is an increasing demand of the F. dibotrys. Fagopyrum esculentum Moench., with a high nutritional value, is widely cultivated in China. In this paper, the author has observed the influences of enhanced UV-B radiation in simulation and drought stress on the biomass accumulation and allocation, leaf photosynthetic pigments, leaf protective substance and protective enzymes of F. dibotrys and F. esculentum, with a comparison about the plasticity of the two buckwheat species under these conditions, in order to study the impact of the enhanced UV-B radiation on plants under drought stress, and so as to provide a theoretical basis for the protection and use of F. dibotrys and the cultivation of F. esculentum.1) Drought stress made the organs’biomass and total biomass accumulation decrease in F. dibotrys and F. esculentum. The decrease became more obvious with the deepening of drought stress. Biomass allocation to root increased significantly with the increasing of drought stress in F. esculentum while showed no obvious regularity in F. dibotrys. There was a trend that biomass allocation to stem and biomass allocation to leaves decreased with the deepening of drought stress in F. dibotrys and F. esculentum. In conditions of adequate water, enhanced UV-B radiation significantly reduced biomass accumulation to root, biomass accumulation to leaves and total biomass accumulation in F. dibotrys and F. esculentum. Enhanced UV-B radiation also reduced biomass accumulation to stem in F. dibotryswhile that of F. esculentum was not sensitive to it. Enhanced UV-B radiation also made biomass accumulation to inflorescence increase in F. esculentum. Enhanced UV-B radiation reduced biomass allocation to root of F. dibotrys while that of F. esculentum was not sensitive to it. Enhanced UV-B radiation could increase biomass allocation to stem in F. dibotrys and F. esculentum. Biomass allocation to leaves of F. dibotrys was not sensitive to enhanced UV-B radiation which reduced that of F. esculentum. Enhanced UV-B radiation could increase biomass allocation to inflorescence of F. esculentum. In conditions of moderate drought stress, enhanced UV-B radiation increased biomass accumulation to root in F. dibotrys and F. esculentum. Enhanced UV-B radiation could improve biomass accumulation to stem in F. dibotrys and F. esculentum, but this improvement reached a significant level only on specific processing time points. Enhanced UV-B radiation made biomass accumulation to leaves of F. dibotrys first decrease and then increase, but increased that of F. esculentum. Enhanced UV-B radiation increased biomass accumulation to inflorescences in F. esculentum. It increased biomass allocation to root in F. dibotrys but decreased that of F. esculentum. Biomass allocation to stem of F. dibotrys and F. esculentum was not sensitive to the enhanced UV-B radiation. Biomass allocation to leaves of F. dibotrys was not sensitive to the enhanced UV-B radiation which could improve biomass allocation to leaves of F. esculentum in a specific period. Biomass allocation to inflorescences of F. esculentum was not sensitive to the enhanced UV-B radiation. In the conditions of severe drought stress, enhanced UV-B radiation also increased biomass accumulation of root in F. dibotrys and F. esculentum. Enhanced UV-B radiation could lead in a certain increase to biomass accumulation to stem in F. dibotrys and F. esculentum, but this effect reached a significant level only on specific points in processing time. Biomass of leaves in F. dibotrys was not sensitive.to enhanced UV-B radiation which significantly increased that of F. esculentum. Enhanced UV-B radiation significantly increased biomass accumulation to inflorescences in F. esculentum. Biomass allocation to root of F. dibotrys was not sensitive to enhanced UV-B radiation which increased that of F. esculentum. Enhanced UV-B radiation had no significant effect on biomass allocation to stem in F. dibotrys and F. esculentum. Biomass allocation to leaves of F. dibotrys was not sensitive to enhanced UV-B radiation which significantly increased that of F. esculentum. Enhanced UV-B radiation reduced biomass allocation to inflorescences in F. esculentum. From the perspective of the phenotypic plasticity index of biomass traits, in UV-B radiation or drought conditions, plasticity of biomass traits of F. esculentum was higher than that of F. dibotrys, and i.e. F. esculentum demonstrated a higher plasticity of biomass traits than F. dibotrys did.2) Chlorophyll a, chlorophyll b and total chlorophyll contents in F. dibotrys and F. esculentum reduced with the severity of drought. In conditions of adequate water, enhanced UV-B radiation reduced chlorophyll a, chlorophyll b and total chlorophyll contents in F. dibotrys and F. esculentum. While under drought stress, chlorophyll a contents of F. dibotrys was not sensitive to enhanced UV-B radiation which could increase chlorophyll a in F. esculentum, chlorophyll b and total chlorophyll contents in F. dibotrys and F. esculentum. The ratios chlorophyll a/ chlorophyll b of F. dibotrys decreased with the severity of drought stress and the decrease was most significantly in the medium-term of the dealing process. Under moderate drought stress, in the medium-term of the dealing process, the ratios of chlorophyll a/chlorophyll b F. esculentum was improved. In whether adequate water or drought stress conditions, the ratios of chlorophyll a/ chlorophyll b was not sensitive to enhanced UV-B radiation. Leaf carotenoid concentratiosns both in F. dibotrys and F. esculentum decreased with deepining drought stress. Only in adequate water conditions, enhanced UV-B radiation increased leaf carotenoid concentratiosns of F. dibotrys. In other water conditions, leaf carotenoid concentratiosns in F. dibotrys and F. esculentum were not very sensitive to enhanced UV-B radiation. In the middle and late dealing process, ratioss of carotenoid/chlorophyll in both F. dibotrys and F. esculentum showed a rising trend with the deepening drought and reached a significant level in the late stage of the dealing process. In adequate water conditions, enhanced UV-B radiation significantly increased ratios of carotenoid/ chlorophyll in F. dibotrys, while in other water conditions, ratioss of carotenoid/chlorophyll in F. dibotrys and F. esculentum were not very sensitive to enhanced UV-B radiation. From the perspective of the plasticity index of photosynthetic pigments, in UV-B radiation or drought conditions, plasticity of photosynthetic pigments in F. dibotrys was higher than that of F. esculentum, and i.e. F. dibotrys demonstrated a higher plasticity of photosynthetic pigments than F. esculentum did.3) SOD activity, total flavonoids contents, MDA contents and soluble sugar contents in F. dibotrys and F. esculentum increased significantly with the deepening drought stress. POD activity rose with the deepening drought stress, reaching a significant level in the medium-term of the dealing process, while in the early and last stages, this effect seemed to wane. In the early and medium stages of the treatment, free proline contents rose with the deepening drought stress but showed no obvious regularity in the later stage. In the early stage of the treatment, soluble protein contents of F. dibotrys rose with the deepening drought stress, but decreased in the medium and late stages. In the early stage of the treatment, soluble protein contents of F. esculentum increased with the severity of the drought, while it was just the opposite issue in the late stage of the treatment. In conditions of adequate water, enhanced UV-B radiation increased SOD activity, total flavonoids contents, free proline contents and MDA contents of F. dibotrys and F. esculentum. In the early and late stages of the treatment, POD activity of F. dibotrys was increased by enhanced UV-B radiation which decreased POD activity of F. esculentum in late stage of the treatment. In the early and late stages of the treatment, soluble protein contents ofF. dibotrys was increased by enhanced UV-B radiation which decreased that of F. esculentum. Enhanced UV-B radiation reduced soluble sugar contents of F. dibotrys and F. esculentum. In conditions of drought stress, enhanced UV-B radiation increased SOD activity of F. dibotrys in the medium-term of the treatment while decreased it in the early and late stages of the treatment. In the late stage of the treatment, enhanced UV-B radiation increased POD activity of F. dibotrys, while decreased that of F. esculentum. Enhanced UV-B radiation decreased total flavonoids contents of F. esculentum in the late stage of the treatment. Enhanced UV-B radiation increased free proline contents of F. dibotrys, while decreased that of F. esculentum in the medium-term of the treatment. Enhanced UV-B radiation increased MDA contents in F. dibotrys and F. esculentum. In conditions of moderate drought stress, enhanced UV-B radiation increased soluble protein contents of F. dibotrys. In the conditions of severe drought stress, enhanced UV-B radiation increased soluble protein contents of F. dibotrys in the early and medium-term of the treatment, but decreased it in the late stage of the treatment. Soluble protein contents of F. esculentum were consistently not sensitive to enhanced UV-B radiation. Enhanced UV-B radiation significantly reduced soluble sugar contents of F. dibotrys, which of F. esculentum was affected only in severe drought stress. In the UV-B radiation and drought treatment, F. dibotrys showed a higher plasticity in protective enzyme and protective substance than of F. esculentum did.In short, enhanced UV-B radiation would not intensify the injury of F. dibotrys and F. emarginatum by drought, but help to improve their resistance to drought to some extent.更多还原