镁对红肉火龙果生长及景天酸代谢相关酶活性的影响  

The Influence of Magnesium on the Growth of Red Pitaya and the Activity of Enzymes Related to Citric Acid Metabolism

作　　者：胡静雯 胡文斌[2,3,4] 陈晖 张惠明 曾祥阳 杨福孙 李洪立 HU Jingwen;HU Wenbin;CHEN Hui;ZHANG Huiming;ZENG Xiangyang;YANG Fusun;LI Hongli(School of Tropical Agriculture and Forestry,Hainan University,Haikou,Hainan 570228,China;Tropical Crop Genetic Re-sources Institute,Chinese Academy of Tropical Agricultural Sciences,Haikou,Hainan 571101,China;Key Laboratory of Crop Gene Resources and Germplasm Enhancement in Southern China,Ministry of Agriculture and Affairs,Haikou,Hainan 571101,China;Key Laboratory of Tropical Crops Germplasm Resources Genetic Improvement and Innovation of Hainan Province,Hai-kou,Hainan 571101,China)

机构地区：[1]海南大学热带农林学院,海南海口570228 [2]中国热带农业科学院热带作物品种资源研究所,海南海口571101 [3]农业农村部华南作物基因资源与种质创制重点实验室,海南海口571101 [4]海南省热带作物资源遗传改良与创新重点实验室,海南海口571101

出　　处：《热带作物学报》2024年第12期2607-2616,共10页Chinese Journal of Tropical Crops

基　　金：2024年海南省育种联合攻关项目“国家火龙果育种联合攻关”;海南省重大科技计划项目“热带果树种质资源精准评价与创新利用”(No.ZDKJ2021014);国家科技资源共享服务平台项目“国家热带植物种质资源库”。

摘　　要：火龙果是海南省的特色热带水果,主要种植于海南省红壤中,其交换性镁常年流失,导致一些果园出现镁缺乏现象,影响火龙果生长及产量。镁参与了光合作用及其他代谢过程,为此本研究以国内主要火龙果品种大红为试验材料,采用水培试验,设置0、0.5、2.0、4.0 mmol/L 4个镁浓度梯度,测定镁对火龙果表观形态、生物量以及景天酸代谢相关酶活性变化。结果表明:(1)不同镁浓度处理对火龙果嫩茎长度、宽度、厚度、茎粗和鲜质量产生很大影响,缺镁或镁过量时嫩茎长度、宽度、厚度、茎粗和鲜重均显著小于2.0 mmol/L镁处理,其中缺镁会使火龙果长度、宽度、厚度、茎粗和鲜质量明显下降,以2.0 mmol/L镁浓度条件最适合植株生长;(2)磷酸烯醇式丙酮酸羧化酶PEPC活性随着镁浓度增加呈先增后降趋势,4.0 mmol/L镁浓度处理PEPC活性低于2.0 mmol/L处理,但活性高于0.5、0 mmol/L处理。在第84天,2.0 mmol/L镁浓度下,嫩茎和老茎PEPC活性较其他处理最高分别为90.44±1.40、92.77±0.67 nmol/(min·g),其初步固定CO_(2)的能力远高于其他处理;苹果酸脱氢酶NAD-MDH活性在嫩茎中随镁浓度增加而呈下降趋势,随着处理时间的延长,镁浓度对NAD-MDH的影响逐渐显现,首先在嫩茎中观察到,然后逐渐影响老茎。在第84天,缺镁处理嫩茎和老茎活性最大分别为(12631.82±286.04)nmol/(min·g)、(10500.16±108.34)nmol/(min·g);在2.0 mmol/L镁浓度处理下火龙果嫩茎和老茎的苹果酸酶NAD-ME活性均维持较高水平,总体平均达到28.41~65.87 nmol/(min·g)。(3)缺镁对嫩茎PEPC和NAD-MDH活性影响有显著差异,缺镁降低了PEPC活性,导致草酰乙酸含量减少,限制了CO_(2)转化为苹果酸的过程。夜间苹果酸积累减少,白天光合作用的原料不足,从而降低了有机物的积累能力。因此,国内红肉火龙果培养中最佳镁浓度为2.0 mmol/L,当前火龙果种植区土壤中镁浓度低于此值,因Pitaya fruit is a characteristic tropical fruit of Hainan province,mainly cultivated in the red soil of Hainan province.The exchangeable magnesium is lost throughout the year,leading to magnesium deficiency in some orchards,which affects the growth and yield of pitaya fruit.Magnesium is involved in photosynthesis and other metabolic processes.Therefore,this study took the main domestic variety of pitaya Dahong as the experimental material,using hydroponic experiments,set four magnesium concentration gradients of 0,0.5,2.0,4.0 mmol/L,to determine the changes in the apparent morphology,biomass,and the activity of enzymes related to crassulacean acid metabolism in pitaya fruit.The results showed:(1)Different magnesium concentration treatments had a significant impact on the length,width,thickness,stem thickness,and fresh weight of the tender stems of pitaya fruit.When magnesium is deficient or excessive,the length,width,thickness,stem thickness,and fresh weight of the tender stems are also significantly less than those treated with 2.0 mmol/L.Magnesium deficiency can significantly reduce the length,width,thickness,stem thick-ness,and fresh weight of pitaya fruit.The condition of 2.0 mmol/L magnesium concentration is most suitable for plant growth;(2)The activity of PEPC first increased and then decreased with the increase of magnesium concentration.The activity of PEPC at 4 mmol/L magnesium concentration was lower than at 2.0 mmol/L but higher than at 0.5 mmol/L and 0 mmol/L treatments.after 84 days,under the condition of 2.0 mmol/L magnesium concentration,the PEPC activity in tender and old stems was the highest among other treatments,at 90.44±1.40 and 92.77±0.67 nmol/(min·g),respectively,and its initial CO_(2) fixation ability was much higher than other treatments;The activity of NAD-MDH in tender stems decreased with the increase of magnesium concentration.With the extension of treatment time,the impact of magnesium concentration on NAD-MDH gradually appeared,first observed in tender stems and then gradually a

关 键 词：镁 火龙果 苹果酸酶 苹果酸脱氢酶 磷酸烯醇式丙酮酸羧化酶 

分 类 号：S31[农业科学—作物栽培与耕作技术]