【作者】 韩艳婷；

【导师】 石雪晖；

【作者基本信息】 湖南农业大学 ， 果树学， 2011， 博士

【摘要】 镁在植物生理作用中有着其它阳离子不可替代的重要地位,植物体内镁离子水平的高低直接影响植物细胞结构、光合作用、酶活化和活性氧代谢等结构和作用及果实品质。近年来,南方葡萄种植园葡萄缺镁现象日趋严重,造成了葡萄体内镁素营养不足,从而影响了葡萄生长发育及鲜果品质的进一步提高。为解决南方葡萄缺镁问题,探讨镁营养对葡萄生理机制及果实品质的影响,在深入研究湖南地区的葡萄叶片镁含量状况基础上,本研究以我国南方近几年广泛种植的优良欧亚种葡萄(Vitis vinifera L.)‘红地球’(Vitis vinifera L.’Red Globe’)为试材,在不同镁营养水平处理下,对葡萄生长发育、体内营养、生理代谢及果实品质的变化进行了研究。研究结果如下：1.湖南地区7个县(市、区)29个葡萄园叶片的N、P、K、Cu含量基本处于适宜范围,Ca含量处于低量范围,Mg含量基本处于缺乏范围,而Zn含量高于适宜范围,Fe, Mn含量也处于适宜范围或以上,植株普遍存在缺镁现象。2.适量供镁能够促进葡萄新梢、叶片、根生长,稳定器官结构：葡萄植株新梢生长,叶面积、比叶重及干重,根系活力、条数、鲜重及干重,均随镁素处理浓度的增高呈先升后降的趋势,仅缺镁(0 mmol·L-1)处理的新梢、叶片、根尖及根边缘细胞内部结构明显破坏,新梢、叶片叶绿体结构变形,片层减少,叶绿体膜破损。3.供镁浓度影响了葡萄体内营养元素的平衡：(1)缺Mg使葡萄各器官Mg含量在处理期内呈下降趋势,其它施镁处理下均有所升高,过量供Mg时,处理后期又有所下降。(2)随Mg2+浓度的增大,葡萄各器官N、P、K、Ca、Fe、Mn含量变化没有明显的规律性,而Mg、Cu、Zn、S呈先下降后上升的趋势,B含量一直呈下降的趋势,但体内Mg含量与镁处理浓度呈显著正相关水平,与N含量呈显著正相关,表现为协同作用,与K、Ca、Mn、Zn含量呈显著负相关,表现为拮抗作用。(3)营养元素的基本分配规律为：(N)叶片>根>叶柄>茎,(K)叶柄>根>茎>叶片,(Ca、Mn)叶片>叶柄>根>茎,(Mg、B)叶柄>叶片>茎>根,(Fe、S)根>叶片>叶柄>茎,(Cu)叶片>根>茎>叶柄,(Zn)叶片>叶柄>茎>根。4.适宜的Mg2+浓度能够稳定细胞结构、提高叶绿素含量和增强光合作用,提高葡萄对光和CO2的利用能力:(1)Mg2+ 3mmol·L-1处理的叶绿体结构规则,而1 mmol·L-1和0 mmol·L-1处理的叶绿体形状发生变化,被膜损坏,结构解体,基粒片层结构被破坏,叶绿体数和体积减少,基粒数和基粒片层减少。(2)缺镁处理时净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)日变化较弱,其Pn、Gs、Tr的日变化曲线均呈双峰曲线型变化,有光合午休现象,随缺镁程度的加大而升高,胞间CO2浓度(Ci)的日变化与Pn和Gs变化趋势相反。(3)葡萄幼苗叶片的叶绿素a(Chla)和叶绿素b(Chlb)含量、Pn、Tr、Gs、Ci、光饱和点(LSP)、最大净光合速率(Pnmax)、表观量子效率(AQY)、羧化效率(CE)均在镁素水平为3 mmol·L-1时显著高于其它浓度水平；而光补偿点(LCP)、CO2补偿点(CCP)、CO2饱和点(CSP)变化趋势相反,镁素用量同光合特性指标呈正相关关系。5.镁素营养影响葡萄叶片的渗透调节物质、活性氧代谢及保护酶活性,适量施加镁肥(约为3 mmol·L-1)有利于葡萄抗膜脂过氧化胁迫和延缓叶片衰老：葡萄叶片中硝酸还原酶(NR)活性、可溶性蛋白(SP)含量、可溶性糖(SS)、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性均随Mg2+浓度增大呈先上升后下降的趋势,与处理浓度呈正相关；脯氨酸(Pro)含量、丙二醛(MDA)含量、超氧阴离子(O2·-)产生速率、过氧化氢(H202)含量变化趋势相反,与处理浓度呈负相关。6.适量供镁可促进果实生长,增加果皮花色苷、白藜芦醇、果实内源激素、营养元素含量,提高果实内在品质：(1)适镁和高镁时果实的生长呈典型的双“S”型曲线,缺镁下两个快速生长期不明显。(2)适镁时果皮中积累花色苷积累速率均快于缺镁和高镁,花后92d果实成熟时,适量的镁果皮中Res含量显著高于缺镁和高镁。(3)三个处理中果实GA3和IAA含量均在花后64d果实转色时含量最高,CTK和ABA含量均在花后50d果实生长前期含量最高,适量的镁果实GA3、IAA、CTK、ABA在花后50d、64d、92d均高于缺镁和高镁处理。(4)三个处理中葡萄果实内N、P、Mg、Fe、Mn、Cu、Zn含量均在花后92d果实成熟时最高,K、Ca含量均在花后64d果实着色时最高,果实内营养元素均以适量镁处理后的含量最高,其次为高镁处理,缺镁处理最低。(5)适镁可提高果实pH值、糖酸比、可溶性固形物、总糖、维生素C、总蛋白、游离氨基酸含量,降低可滴定酸含量。更多还原

【Abstract】 Magnesium (Mg) which is un-substitutable by other cation plays an important role in the physiological process of plants. Its content affects not only the structure of plant cell, photosynthesis, enzyme activity & metabolism of active oxygen metabolism etc., but also the quality of fruit. In recent years, the deficiency of Mg in Sorthern grape planted soils has often been reported. In case of Mg deficiency, the whole physiological metabolic activity will be largely affected and the growth of plants will be influenced. To solve the problem of Mg deficiency in grape and to investigate the impact of Mg to the growth and the quality of grape, this study analyzes and estimated the Mg content of grape leaves in Hunan. In this study,’Red Globe’grape (Vitis vinifera L.), a great breed of Vitis vinifera which was planted widely in recent years in the south of China, was studied for growth and development, nutrition contents, physiological metabolism and fruit quality in different Mg treatments. The results are as follow:1. The contents of N, P, K, Cu all were in the appropriate range, the Ca content in the low range, the Mg content in the lack range, but the Zn content higher than the suitable range, the Fe, Mn contents in the suitable range or above it of leaves in 7 counties in Hunan Province (cities, districts) in 29 vineyards. Therefore, the widespread leaves yellow in Hunan vineyards was not caused by the deficiency of N、P、K、Fe、M、Cu、Zn, also not possible by the few Ca. But it was related with the Mg lack.2. The rational application of Mg fertilizer could promote the grape shoot, leaf, root growth and significantly stabilize and integrate ultrastructure of various organelles.The growths of new grape shoot elongation, the leaf area, dry weight and root activity, the main root section, the root fresh weight and dry weight were ascend in first and descend at last. When the Mg concentration is 0 mmol·L-1, the new shoots, leaf cells, root tip and root border cells were significantly damaged. New shoots, leaf and chloroplast structure were distortion, the leaf layers reduced and chloroplast membrane damaged, in contrast, no different was observed in other treatments. 3. Therefore, the offering Mg concentration affected the balance of nutrient elements in grapes. (1)In the level of lacking Mg, Mg content of grape organs decreased in the treatment period. As the Mg content increasing to normal, Mg content of all organs were increased with the processing time. If offering excessive Mg, it decreased in the late period of treatment. (2) At different levels of Mg nutrition, the influence was different to N, P, K, Ca, Fe in organs of grape. Mn content varyed degrees, but no obvious regularity. With the Mg2+ concentration increasing, Mg, Cu, Zn, S in different organs decreased first, but then increased. B content showed a downward trend, but there was a remarkable positive correlation between Mg content and Mg concentration, showing synergistic to each other. And there was a significantly positively correlation between Mg content and K, Ca, Mn, Zn showing an antagonism effect.(3) At different levels of Mg nutrition, the basic rules for nutritional elements the allocation in different grape seedling is:(N)leaf> root> petiole>stem, (K) petiole> root> stem> leaf, (Ca, Mn) leaf> petiole> root> stem,(Mg, B) petiole> leaf> stem> root, (Fe, S)root> leaf> petiole> stem, (Cu) leaf> root> stem> petiole, (Zn) leaf> petiole> stem> root.4. Suitable magnesium concentration could not only improve the light and CO2 utilization ability, but accelerated the growth of grape. (1) In the 3 mmol·L-1 Mg2+ treatment, numbers of normal chloroplasts were found that they contain lots of big starch grains, the grana and strom were observed obviously. The chloroplast ultrastructure was not obviously injured in the 5 mmol·L-1 treatment, while in the 0 mmol·L-1 and 1 mmol·L-1 treatment, a series of chloroplast configuration changed, and structure of grana and stroma lamellae were destroyed. (2) The diurnal variation of the photosynthetic rate (Pn)、transpiration rate (Gs) and stomatal conductance (Tr) of Mg fertilizer changed in the double- curve in daytime, indicating there were midday depression, and they decreased with the decrease of magnesium supply,and diurnal variation of intercellular CO2 concentration (Ci) was contrary to that of Pn and Gs. (3) The content of chlorophyll a(Chla), chlorophyll b(Chlb) and total chlorophyll(Chl(a+b)), the Pn, Tr, Gs, Ci, the light saturation point (LSP), the maximum net photosynthetic rate (Pnmax), apparent quantum yield (AQY) and carboxylation efficiency(CE) were significantly higher than other magnesium treatments, and they increased and then declined with the increasing of magnesium concentration. The change tendency of the ratio of Ch1 a/Ch1 b, light compensation point (LCP), CO2 compensation points (CCP) and CO2 saturation point (CSP) was opposite. There were non-linear positive correlations between Mg application rates and photosynthetic properties.5. Therefore, Mg nutrition affected the qsmotic adjustment, active qxygen metabolism and antioxidant enzymes in grape leaf. The suitable amount of Mg fertilizer (approximately 3 mmol·L-1) could protected the structure and function of cell membrane, and it was beneficial to resist lipid peroxidation and delayed leaf senescence. With the increasing of Mg2+ concentration, nitrate reductase (NR) activity, soluble protein (SP), soluble sugar (SS), superoxide dismutase (SOD) and peroxidase (POD) activity, catalase (CAT) activity in grape leaf were first increased and then decreased, showing a positive correlation with the concentration. But the contents of proline (Pro), malondialdehyde (MDA), superoxide anions (O2·) production rate, hydrogen peroxide (H2O2) were the opposite trend, showing a negative correlation with the concentration.6. The rational application of Mg fertilizer could promote fruit growth, increase fruit anthocyanins, resveratrol, fruit endogenous hormones and nutrient content, and improve fruit quality. (1) Under the appropriate Mg or excess Mg, The growth of Red Globe grape showed a typical double "S" curve, and under magnesium deficiency, the two fast growing periods were not clear. (2) Suitable amount of Mg inproved the content of anthocyanins and resveratrol (Res).The accumulation rate of Anthocyanin under fruit skin was faster with appropriate Mg than with lack and excess Mg. When the 92d after flowering, the content of Res with appropriate Mg was significantly higher than lack and excess Mg. (3) When the color of fruit was changed, GA3 and IAA in the three treatments were the highest in the 64d after flowering. But early fruit growth CTK and ABA were the highest in 50d after flowering. In the fruits with appropriate Mg, GA3, IAA、CTK、ABA were higher than lack or excess Mg treatment in the 50d,64d,92d after flowering. (4)In the three treatments, the content of N, P, Mg, Fe, Mn, Cu, Zn of the mature fruit was the highest in the 92d after flowering. K, Ca content was the highest in the 64d after flowering while the fruit was coloring. All nutrients were the highest in appropriate Mg, followed by high-magnesium treatment. Mg deficiency reatment was the lowest. (5) Suitable magnesium could increase the pH value of the fruit, sugar acid ratio, soluble solids, total sugar, vitamin C, total protein, free amino acid content, lower titratable acid.更多还原