植物镁素营养诊断及镁肥施用

本文对近些年来有关镁素营养诊断及镁肥施用问题作了综述。主要内容包括：缺镁时植物的外部形态表现及内部结构变化、植物镁素化学分析诊断和生物化学方法诊断以及镁肥施用技术和国内镁肥使用状况。     

土壤镁素和镁肥施用的研究

本文综述了土壤镁素，植物镁素营养以及镁肥施用方面的研究成果，土壤镁素可分为矿物态、非交换态、交换态、水记和有机态等５种形态，它们对植物的有效性不同，非交换性镁的释放量很低，难以满足作物对镁素的需求，在酸性较强的土壤上施用缓产性镁肥对作物具有良好的效应。镁对碳水化合物，蛋白质，脂肪等物质代谢及能量转化有相当重要的作用，作物对镁素的吸收受到环境因素，特别是阳离子竞争效应的影响。     

镁肥与添加剂施用后土壤镁迁移与淋洗特征研究

通过室内土柱试验,模拟了镁肥及不同用量添加剂包括生物质炭、有机肥、石灰施用土壤后镁素的有效性及迁移淋溶特征.结果表明:施用添加剂后均不同程度提高施肥土层(0～15 cm)土壤pH.施用镁肥、生物质炭、50％需求量石灰与3.3、6.6 g/kg有机肥后,施肥土层交换性镁含量显著增加,而10 g/kg有机肥与100％、20...     

基于土壤钙镁比的毕节植烟区镁肥施用分区研究

当前植烟区土壤镁肥施用主要依据土壤有效镁含量水平及其空间分布特征确定,但很少考虑到土壤钙镁比(有效钙含量/有效镁含量)对土壤镁素供应的现实影响,这必然对镁肥施用效果产生不利影响。本研究以毕节植烟区为例,基于大样本土壤采样数据,综合考虑土壤有效镁含量水平、土壤钙镁比及两者的空间分布特征,通过图形叠加和栅格运算,科学划定植烟区土壤镁肥宜施等级及分区。研究表明,毕节植烟区土壤有效镁平均含量为278.1 mg·kg^-1,土壤钙镁比均值为14.5,空间上均呈现较强的波动性。从空间插值图看,土壤有效镁含量以适宜等级为主,占到毕节植烟区面积的69%,土壤钙镁比分布以10～20和5～10两等级为主,且各等级交错分布。基于土壤有效镁含量和钙镁比获得的土壤镁肥宜施等级图中,适宜和较适宜施用镁肥面积分别为69.0%和10.5%,不适宜施用面积为19.0%,而极适宜和极不适宜面积比例仅分别为1.3%和0.2%。若仅考虑土壤有效镁含量得到的宜施等级分布与考虑钙镁比的宜施等级分布存在很大差异,这说明在制定镁肥施用方案时,若不考虑钙镁比对土壤镁素供应的影响,得到的镁肥宜施等级分区会产生较大的偏...     

秸秆还田下施镁对土壤交换镁及春玉米镁素积累和产量的影响

于2017—2019年在吉林省农安县设置大田试验,采用双因素裂区设计,主区为秸秆还田J(12000 kg/hm^2)、秸秆不还田W,副区为施镁M3(施纯镁10 kg/hm^2)、不施镁M0,包含JM3(秸秆+镁肥)、JM0(秸秆+无镁肥)、WM3(无秸秆+镁肥)、WM0(常规)4个处理。结果表明:玉米生育期,土壤交换镁含量逐渐降低,至成熟期,JM3处理土壤交换镁含量比WM3、JM0、WM0分别提高6.59%,8.47%,14.09%。施用镁肥促进玉米植株对镁素养分的吸收,秸秆还田配施镁肥进一步增加了玉米植株对镁素养分的吸收,WM3处理玉米镁素积累量比WM0平均提高12.30%;JM3处理的镁素积累量比WM3、JM0、WM0处理分别提高9.79%,15.99%,23.28%。春玉米干物质积累量随着生育期的进行逐渐增加,施镁肥能提高干物质积累量与春玉米产量,在成熟期WM3(无秸秆+镁肥)的干物质积累量与产量分别比WM0(常规)提高5.30%与4.38%,JM3(秸秆+镁肥)的干物质积累量与产量比WM0(常规)分别提高11.50%与5.52%。综上可以得出,施用镁肥可以显著提高土壤交换镁含量,促进春玉米植株对镁素养分的吸收,增加干物质积累量及提高春玉米产量。秸秆还田配施镁肥不但可以提高土壤交换镁含量,保持土壤镁素在整个玉米生育期的持续有效供应,还进一步促进春玉米植株对镁素的吸收,提高了干物质积累量及春玉米产量。     

红壤区土壤中镁肥肥效的研究

虽然早在一个世纪以前,就已经知道镁是植物正常生长所必需的养分之一,但道到本世纪三十年代才开始施用镁肥.最近,对镁的作用和镁肥施用间题.给予了较大的注意^p[1,2].这是由于镁在植物营养上的重要作用日益为人们所了解;以往认为是由病害所引起的一些症状,查明了往往是由镁素缺乏而引起;随着氮、磷、钾等化学肥料的大量施用,农作物产量增加,但由于没有相应地施用镁肥,加剧了土壤中镁素的缺乏.在某些国家,过去随钾肥可带入一些镁素,但后来由于肥料的精制提纯,这种无意的施用也停业了,因而作物缺镁症状增多.     

灌水、石灰和镁肥水平对玉米干物质积累和镁素利用的影响

研究了2种灌水水平、3种石灰水平和3种镁肥水平对玉米干物质积累及镁(Mg)素利用的影响。结果表明,灌水能提高玉米干物质积累和玉米对Mg的吸收;施用石灰不明显影响玉米干物质积累,但降低玉米对Mg的吸收,增加土壤对Mg的固定,对Mg肥表观有效率的影响因施用量不同而有所不同。施用Mg肥在一定程度上提高玉米干物质积累,明显增加Mg的吸收和土壤交换性Mg含量。因此玉米对Mg的吸收利用不仅受到土壤Mg供应水平的制约,而且也受到灌水、施用石灰等因素的影响。     

山西省主要类型土壤镁素供应状况及镁肥施用效果

采用田间调查、土壤盆栽和大田试验相结合的方法,研究山西省主要类型土壤镁素供应状况及镁肥施用效果.结果表明,山西省主要类型土壤耕层(0-20 cm)交换性镁含量在78.1～641.8 mg/kg范围内.平均含量为255.1 mg/kg.不同类型土壤交换性镁含量高低依次为潮土>褐土>栗褐土>石灰性褐土>黄绵土>褐土性土.土壤交换性镁含量与土壤主要化学性质密切相关.生物消耗试验表明,褐土和石灰性褐土的镁生物有效性较高,其次是褐土性土和黄绵土,栗褐土和潮土的镁生物有效性最低.与不施镁肥相比,施镁大豆增产2.77%～9.04%,玉米增产2.98%～10.21%;大豆籽粒粗蛋白含量提高4.56%～7.52%,玉米籽粒粗蛋白、总淀粉和总糖含量分别提高9.96%～15.36%,2.41%～6.42%和8.52～12.50%.相关分析表明,大豆籽粒中镁含量与籽粒产量、粗蛋白和粗脂肪含量呈显著线性正相关;玉米籽粒中镁含量与籽粒产量呈显著线性正相关,与粗蛋白含量呈曲线关系,而与粗脂肪含量呈现显著线性负相关.研究表明,山西省主要类型土壤交换性镁含量处于较高水平,不同类型土壤交换性镁含量及生物有效性存在显著差异,籽粒中镁与籽粒蛋白质和脂肪含量密切相关,适量施用镁肥可提高农作物产量、改善营养品质.     

漳州香蕉园土壤镁素分布状况及施镁效应研究

121个蕉园土壤样品(0～40cm土层)分析结果表明，漳州缺镁蕉园土壤占36．4％，在缺镁地块上进行了为期二年的定位试验，以探讨施用不同镁肥的效果，结果表明：施用不同镁肥处理比对照的香蕉产量都有不同程度的提高，增长效果达显著水平：香蕉施用Mg(OH)2处理比不施用镁肥(对照)处理的产量增长达到极显著水平，两年分别增产10．18％和10．52％。因此，在缺镁蕉园施肥上应适量而又平衡的施用镁肥。     

漳州香蕉园土壤镁素分布状况及施镁效应研究

12 1个蕉园土壤样品 (0～ 4 0cm土层 )分析结果表明 ,漳州缺镁蕉园土壤占 36 4 % ,在缺镁地块上进行了为期二年的定位试验 ,以探讨施用不同镁肥的效果 ,结果表明 :施用不同镁肥处理比对照的香蕉产量都有不同程度的提高 ,增长效果达显著水平 ;香蕉施用Mg(OH) 2 处理比不施用镁肥 (对照 )处理的产量增长达到极显著水平 ,两年分别增产 10 18%和 10 5 2 %。因此 ,在缺镁蕉园施肥上应适量而又平衡的施用镁肥     

水稻缺镁症及镁肥试验效果初报

水稻生长发育所必需的营养元素 ,除氮、磷、钾外 ,钙、镁、硫也是同等重要的。水稻缺钙、缺硫时有发生 ,而缺镁则稀见报道。针对我市出现较大面积缺镁症状的实际情况 ,经过连续三年的施用镁肥试验 ,取得较好的增产效果。1　缺镁症及发生特点1 998年 6月初 ,在本市陶冲镇联河村发现了早稻黄叶矮缩现象。其主要症状表现为淡绿色 ,分蘖明显减少 ,植株矮小 ,略有披叶 ,严重的全株黄枯 ,发生部位先出现在下部老叶 ,表现为脉间失绿黄化 ,叶尖叶缘发生黄枯。症状多在早稻插秧 7天后开始发生 ,分蘖盛期表现明显 ,拔节后症状减轻消失。经施镁诊断性试…     

The Magnesium Status of Some Fiji Soils

Abstract

Magnesium (Mg) is an essential macronutrient element for all living organisms, but literature reports of Mg deficiency in agriculture and forestry appear regularly. In many tropical areas, Mg is added to soils by using dolomitic limestone and as minor additions through impurities in some fertilizers. Minimal information is available on the Mg status of Fiji soils, and deficiencies have been observed in some crops. This study investigated the Mg status of a range of Fiji soils and found that major agricultural soils of Fiji contain variable amounts of Mg, both in the total concentrations and in the different forms of the element present. The variations can be related to the soil parent materials, degree of weathering, clay content, and mineralogy. Low plant‐available Mg concentrations are present in many of the highly weathered soils with limited reserves present. Development of intensive agriculture should consider Mg when developing fertilizer programs.     

镁原卟啉Ⅸ甲基转移酶研究进展

镁原卟啉Ⅸ甲基转移酶(ChlM)是叶绿素合成过程中的关键酶,对光合自养生物中叶绿素合成、叶绿体的正常发育以及光合作用的顺利进行起到至关重要的作用。ChlM不仅影响着光系统Ⅰ(PSⅠ)和光系统Ⅱ(PSⅡ)的形成以及脱落酸(ABA)的信号转导,还可以通过调控镁螯合酶H亚基基因(ChlH)表达而影响镁螯合酶活性。ChlM的产物可能参与叶绿体到细胞核的反向信号转导,同时,ChlM受到光照、叶绿体内氧化还原状态和叶片中叶酸含量等因素的影响。本文主要综述镁原卟啉Ⅸ甲基转移酶的结构特点、作用机制、酶活性调控及其参与的代谢调节,并展望镁原卟啉Ⅸ甲基转移酶的研究前景,以期为进一步深入研究并提高植物光合效率提供参考。     

Effect of Calcium/Magnesium Ratio in Soil on Magnesium Availability,Yield, and Yield Components of Maize

Abstract

The effect of calcium (Ca)/magnesium (Mg) ratio in the soil on Mg availability, yield, and yield components of maize (Zea mays L.) was investigated both in the greenhouse and the field at eight different Ca/Mg ratios ranging from 1∶1 and 8∶1. In the greenhouse, exchangeable Ca/Mg ratios of 2∶1 to 3∶1 gave optimum yield of maize without Mg‐deficiency symptoms. The Ca/Mg ratios in the soil were positively and significantly correlated with Ca content and negatively and significantly correlated with Mg content. The Ca/Mg ratio in the soil was also positively and significantly correlated with observed Ca/Mg ratio in the maize plant tissue. The Ca/Mg ratio in the soil could be a limiting factor for Mg nutrition of the maize plant. Under field conditions, exchangeable Ca/Mg ratios in the soil showed no significant effects on the Ca and Mg contents of the maize earleaf. However, optimum maize yield was obtained at an exchangeable Ca/Mg ratio of 6∶1.     

Aluminium Induced Magnesium Deficiency in Oats

It was the objective to study the effect of Al on Mg uptake by plants, precluding as far as possible the effect of Al on root growth. Oat plants were grown in a complete standard nutrient solution without any differential treatment, in order to obtain a set of plants which did not differ in the size, the morphology and the physiology of the root system. After the first harvest at the beginning of the stem elongation stage 4 different treatments were introduced: pH 5.5-6.0, pH 5.5-6.0 without Mg, pH 3.8-4.1, pH 3.8-4.1 + 0.3 mmole Al/l. Apart from these variations the composition of the nutrient solution remained unaltered. After another 10 days 2 vessels of each treatment were harvested. The final harvest was 14 days after the beginning of the differential treatments. The growth (in terms of dry matter yield) of neither the shoots nor the roots was adversely affected by the differential treatments, although the plants in the Al and Mg₀ treatments showed distinct symptoms of nutritional disorder. The plants in the low and the high pH treatments differed neither in Mg uptakte nor in Mg concentration in the plants. However, the addition of Al to the nutrient solution reduced Mg uptake in the shoots to about 30% of that in the Al₀ treatments, while there was a net loss of Mg in the roots in spite of the fact that dry matter increased. This means that net uptake of Mg was less than was translocated to the shoot during the period of differential treatments. With no Al in the nutrient solution the Mg concentration in the shoots declined by 3–8% between the first and the final harvest, whereas it increased by 22–35% in the roots. If, however, Al was added to the nutrient solution the Mg concentration dropped by 46% in the shoots and 70% in the roots. With the exception of Ca in the roots, the differential treatments had no effect on the uptake and concentration of Ca, K and P in the plants. In terms of dry matter the differential treatments did not influence root growth and it was concluded that Al had a direct effect on Mg uptake by either inactivating or competing for uptake sites or carriers.     

Effect of Two Magnesium Fertilizers on Leaf Magnesium Concentration,Yield, and Quality of Potato and Sugar Beet

Twelve field experiments were conducted to study the impacts of calcined magnesite and Kieserite fertilizers on yield, quality and leaf concentrations of magnesium (Mg) in potatoes and sugar beet. The rate of Mg applied was 60 kg Mg ha^?1, and the experiments were realized in six locations for both crop species. There were clear increases in leaf Mg concentration and yield of both crops resulting from application of Mg fertilizers. Mean increase in leaf Mg concentration and crop yield for both species were more pronounced with Kieserite than with calcined magnesite. Sugar concentrations of sugar beet and dry matter yield of potatoes were, however, influenced only slightly by the Mg fertilizers. It seems that superiority of Kieserite to calcined magnesite is related to higher Mg solubility of Kieserite. Use of Mg fertilizers with higher solubility helps to avoid the risk of Mg deficiency and subsequent losses in yield and economic returns.     

生物镁离子转运体研究进展

镁(magnesium) 是生物生长发育必需的核心营养元素之一,也是细胞中含量最多的两价阳离子。镁具有最大的水合半径,最小的离子半径和最大的电荷密度,特殊的理化性质使其在生物体内的转运方式显得尤为重要。以前的研究大多集中在物化结构,生理功能,缺镁病理等方面,并在光合作用,酶的活化,基因组稳定,抑制衰老,减轻铝害和调节氮代谢等研究方面取得了一定的成就,但 Mg2+转运蛋白的晶体结构,Mg2+吸收、转运和体内平衡的分子机理,Mg2+胁迫信号的传导机制等信息仍知之甚少。人们已经从许多生物中克隆了 Mg2+转运相关基因,包括原核生物、低等真核生物、高等真核生物,并对其结构、功能、亚细胞定位进行了分析验证。根据已知镁离子运输体的不同结构或功能,把它们分为 6 个不同的家族:钴抗性蛋白家族(CorA),Mg2+/H+交换体(AtMHX),离子通道,P 型磷酸酶(P-type phosphatase),Mg2+转运体基因家族MgtE (MgtE )和其它镁离子运输家族。同一家族的不同成员之间存在结构或功能的相似性,其中,CorA 家族的镁离子运输体是最基本、研究最深入的运输体,它们广泛的存在于细菌,酵母菌,动物和植物中,能调节镁离子的吸收和外排。本文对已发现的各种 Mg2+转运体的结构功能特点进行了综述,以期为该领域的研究提供一些有益的参考。