基于叶绿素叶面分布特征的黄瓜氮镁元素亏缺快速诊断

为了快速、无损诊断作物氮(N)、镁(Mg)营养亏缺,该研究提出一种以叶绿素叶面分布特征诊断黄瓜N、Mg元素亏缺的方法。在设施栽培模式下精确控制N、Mg营养元素的供给,培养黄瓜缺N、缺Mg及对照植株(营养元素正常植株),然后采集对应的高光谱图像并结合化学计量学方法快速、无损检测叶绿素分布。与对照组叶片叶绿素分布相比,缺N叶片的叶绿素含量在整个叶面区域偏低,缺Mg叶片叶绿素在叶脉之间区域含量偏低。鉴于此,提取叶绿素叶面分布特征(叶片所有像素点对应的叶绿素含量均值及标准差)对N、Mg营养元素亏缺进行诊断,对预测集N、Mg元素亏缺正确诊断率达90%。研究结果表明叶绿素叶面分布特征可作为一种黄瓜N、Mg元素亏缺诊断依据。     

缺镁对菜豆幼苗膜脂过氧化及体内活性氧清除酶系统的影响

营养液中培养菜豆幼苗,缺镁菜豆植株生长受抑,生物量显著低于正常供应镁的植株,体内镁浓度和镁的积累总量均较低。严重缺镁黄化叶片中叶绿素含量下降。完整叶绿体的希尔反应值在缺镁与正常植株间无差别。缺镁菜豆植株的根和叶膜造性（以相对电导率表示）增加,叶片中丙二醛含量升高。活性氧清除酶系统:SOD、POD、CAT活性在缺镁菜豆真叶中高于正常植株,老叶中抗坏血醒过氧化物酶（AsA-POD）活性增加程度也较大。     

Increasing root and leaf growth and yield in Mg‐deficient faba beans (Vicia faba) by MgSO4 foliar fertilization

Magnesium (Mg) deficiency reduces yield and quality of crops as Mg is involved in carbohydrate and protein anabolism. Foliar application of MgSO₄ represents a means of ameliorating the nutritional status of crops growing under conditions of deficiency. Foliar Mg application has been demonstrated to increase the chlorophyll concentration and vegetative yield of plants. However, in crop plants used for seed production, the limited number of available studies provides only conflicting results in terms of the efficiency of Mg leaf application on yield and quality. We have examined the effect of increasing Mg foliar application rates on differentially developed leaves and leaf stages with regards to Mg concentration, chlorophyll concentration and biomass formation. Our data reveal that in order to obtain significant effects MgSO₄ concentrations in the spraying solution should be higher than 50 mM, as lower concentrations did not lead to significant changes in the vegetative or generative material. Positive effects of the foliar application on chlorophyll concentration and leaf area were only measured in leaves treated with 200 mM foliar MgSO₄. The application of Mg did not affect the parameters chlorophyll, ion concentration and leaf area in the newly developing leaves, but it had an important influence with regard to yield traits, especially on the formation of pods. The quality of the seeds with regard to the protein concentration was reduced in response to the magnesium deficiency treatment, but the application of foliar magnesium prevented a significant loss of protein.     

高钾供应加剧了水稻叶片缺镁诱导的氧化胁迫

Magnesium （Mg） deficiency in plant affects photosynthesis and many other metabolic processes. Rice （Oryza sativa L. cv. ＇Wuyunjing 7＇） plants were grown in hydroponics culture at three Mg and two potassium （K） levels under greenhouse conditions to examine the induction of oxidative stress and consequent antioxidant responses in rice leaves due to Mg deficiency. At low Mg （0.2 mmol L 1 Mg supply for two weeks after transplanting） and high K （6 mmol L^-1） for 21 days, the rice plants showed severe Mg deficiency and a significant decreases in the dry matter production. The Mg deficiency in leaves decreased chlorophyll concentrations, photosynthetic activity, and soluble protein, but significantly increased the concentrations of soluble sugars and malondialdchyde （MDA） and the activities of superoxide dismutase （SOLD, EC 1.15.1.1）, catalase （CAT, EC 1.11.1.6） and peroxidase （POD, EC 1.11.1.7）. In addition, Mg concentrations in the leaves and in the shoot biomass were negatively related to the activities of the three antioxidative enzymes and the concentration of MDA in leaves. There were very significant interactive effects between Mg and K supplied in the culture solution on shoot biomass yield, chlorophyll content, photosynthesis rate, the activities of SOD, CAT and POD, and MDA content in the leaves of rice. It is suggested that the high K level in the nutrient solution aggravated the effect of low Mg supply-induced Mg deficiency and created the oxidative damage in rice plants.     

Is the photometric method using acetone extracts to determine chlorophyll concentrations applicable to Mg‐deficient plants?

A conventional photometric method to determine chlorophyll concentrations in maize leaves was evaluated. It was tested whether in Mg‐deficient plant tissue the addition of MgCO₃ during pigment extraction converts protoporphyrin IX into chlorophyll, falsifying concentration measurements. The non‐destructive N‐tester was used as a reference for the destructive chlorophyll determination. It is shown that both methods are valid for the determination of chlorophyll concentration in Mg‐deficient leaves.     

Magnesium deficiency–induced impairment of photosynthesis in leaves of fruiting Citrus reticulata trees accompanied by up‐regulation of antioxidant metabolism to avoid photo‐oxidative damage

Limited data are available on the physiological responses of leaves from fruiting trees to magnesium (Mg) deficiency. Magnesium deficiency–induced effects on photosystem II (PSII) photochemistry in leaves of fruiting (Citrus reticulate cv. Ponkan) trees were assessed by the chlorophyll a fluorescence (OJIP) transient. Magnesium deficiency decreased leaf CO₂ assimilation and carbohydrates, but had no effect on intercellular CO₂ concentration. Activity of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) and concentrations of Chlorophyll (Chl) and carotenoids (Car) decreased to a lesser extent than CO₂ assimilation. Chlorophyll a fluorescence transient from Mg‐deficient leaves had increased O step and decreased P step, accompanied by positive ΔL, ΔK, ΔJ, and ΔI bands. Magnesium deficiency decreased maximum quantum yield of primary photochemistry (F_v/F_m), quantum yield of electron transport from Q<$>_A^‐<$> to the photosystem I (PSI) end electron acceptors (φ_R0), maximum amplitude of IP phase and total performance index (PI_{tot, abs}), but increased deactiviation of oxygen‐evolving complex (OEC) and energy dissipation. Magnesium‐deficient leaves had higher or similar activities of antioxidant enzymes except for lower catalase (CAT) activity, higher or similar concentrations of antioxidant metabolites, and a higher ratio of Car : Chl. Magnesium‐deficiency did not affect concentration of malondialdehyde (MDA) and ratios of ascorbate (ASC) to ASC + dehydroascorbate (DHA) and reduced glutathione (GSH) to GSH + oxidized glutathione (GSSG). In conclusion, Mg deficiency–induced impairment of the whole photosynthetic electron transport chain may be the main factor contributing to decreased CO₂ assimilation. Enhanced energy dissipation and antioxidant metabolism provide sufficient protection to Mg‐deficient leaves against photo‐oxidative damage.     

Distribution of magnesium between chlorophyll and other photosynthetic functions in magnesium deficient “sun”; and “shade”; leaves of poplar

Photosynthesis of attached sun and shade grown leaves of poplar (Populus euramericana (Dode) Guinier cv. ‘Robusta') has been measured at 0.03 and 0.5% CO₂ at light limitation and light saturation. Photosynthetic rates were compared for plants grown at normal and low Mg‐supply and related to leaf Mg content.

Photosynthetic rates at high CO₂ level were affected at Mg concentration lower than about 50 μmoles/g dry leaf tissue at both photosynthetic irradiations. This was paralleled by a decrease in chlorophyll concentration. At a low CO₂ level photosynthesis was affected at the same Mg concentration but the degree of the inhibition was higher. This indicates that synthesis of chlorophyll as well as CO₂ fixation are affected at the same “critical”; Mg concentration.

Shade leaves contain more chlorophyll per unit leaf weight than sun leaves but the percentual‐ decrease of chlorophyll in Mg deficient leaves Is similar for sun and shade leaves at the same Mg leaf concentration. As a consequence, in Mg deficient shade leaves extraordinary high portions of leaf Mg are bound to chlorophyll (up to 57%; in contrast: up to 37% in sun leaves).     

Distribution of nutrient elements along the maize leaf: Alteration by iron deficiency

Distribution often elements along the maize leaf and the effect of iron (Fe) deficiency on these distributions were studied using plants grown in nutrient solution. In both the control and Fe‐deficient leaves, the concentrations of Fe, calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), and boron (B) increased and only that of potassium (K) decreased from leaf base to the leaf tip. Nitrogen (N) and copper (Cu) were the only two elements which showed no gradient of concentration along the entire leaf. Iron deficiency decreased the concentration of Fe by the same extent along the entire leaf length. However, it differentially accentuated the uneven distribution of some elements along the leaf length. For example, Fe deficiency increased the concentrations of Cu and N somewhat uniformly along the whole length the leaf; those of P and K were increased only along the lower two‐thirds of the leaves; and those of Ca, Mg, B, Zn, and Mn mostly along the upper one‐half to one‐third of the leaf length. Potassium was the only element whose concentration was lower at leaf tip than at the leaf base under both Fe‐sufficient and Fe‐deficient conditions. My results indicate that the basal half of maize leaf may be a more suitable part for diagnostic purposes since the concentration of most elements is less subject to alteration in this region, especially if a latent or obvious Fe deficiency is present. In view of these observations, the use of the entire maize leaf for diagnostic purposes may have to be reevaluated.     

硝普钠对黄瓜幼苗缺镁和硝酸盐胁迫的缓解效应

【目的】设施栽培中土壤次生盐渍化严重,导致植株出现缺镁失绿症状。通过研究硝酸盐胁迫下外源NO供体(硝普钠,SNP)对缺镁黄瓜幼苗生长的影响,探究硝酸盐胁迫下外源NO对缺镁黄瓜幼苗的胁迫缓解效应,为解决设施生产中黄瓜幼苗的缺镁失绿症状提供理论指导。【方法】采用水培的方式培养黄瓜幼苗,幼苗长至三叶一心时进行处理。营养液采用山崎配方,镁离子浓度设两个水平为2 mmol/L(正常浓度)和1 mmol/L(缺镁胁迫);硝酸盐浓度设两个水平为14 mmol/L(正常浓度)和140 mmol/L(硝酸盐胁迫);硝酸盐和镁正常浓度为对照。用0.1mmol/L SNP分别缓解缺镁胁迫、硝酸盐胁迫以及缺镁和硝酸盐双重胁迫,用0.1 mmol/L SF(铁氰化钠)处理,观察SNP反应产物的影响;NO-3由Ca(NO3)2·4H2O和KNO3提供,各占1/2,p H由H2SO4调节,保持在5.5 6.5。【结果】1)缺镁胁迫下,黄瓜幼苗株高和叶面积增加值、干物质增长量较正常处理的黄瓜幼苗显著降低;电解质渗漏率、丙二醛含量和可溶性蛋白含量较正常处理的黄瓜幼苗显著升高。缺镁处理的黄瓜幼苗根茎叶中镁离子含量、叶片光合色素含量、光合特性指标、叶绿素荧光及抗氧化酶活性与正常处理的黄瓜幼苗相比明显降低。2)硝酸盐胁迫下,黄瓜幼苗株高和叶面积增加值、干物质增长量、黄瓜幼苗根茎叶中镁离子含量、叶片光合色素含量、光合特性指标、叶绿素荧光及抗氧化酶活性较正常处理的黄瓜幼苗显著降低;电解质渗漏率、丙二醛含量和可溶性蛋白含量较正常处理的黄瓜幼苗显著升高。3)缺镁和硝酸盐双重胁迫下,黄瓜幼苗的相关生长指标和抗逆指标较正常处理的黄瓜幼苗降低或增大更为显著。4)缺镁胁迫,硝酸盐胁迫以及缺镁和硝酸盐双重胁迫下,外施0.1 mmol/L SNP处理的黄瓜幼苗,株高和叶面积增加值、干物质增长量、幼苗根茎叶中镁离子含量、叶片光合色素含量、光合特性指标、叶绿素荧光、可溶性蛋白含量及抗氧化酶活性较未添加SNP处理的黄瓜幼苗显著提高,电解质渗漏率和丙二醛含量则明显降低。外施0.1 mmol/L SF则没有表现出明显的作用。【结论】硝酸盐胁迫下缺镁黄瓜幼苗生长受到明显抑制,出现失绿症状,通过添加0.1 mmol/L SNP,黄瓜幼苗的生长抑制得到明显缓解,说明在硝酸盐胁迫下外源NO对缺镁黄瓜幼苗的胁迫有显著缓解作用,增强黄瓜幼苗的耐盐性和对镁的吸收能力。     

Activities of Iron‐Containing Enzymes in Leaves of Two Tomato Genotypes Differing in Their Resistance to Fe Chlorosis

Abstract

Two tomato (Lycopersicon esculentum Mill., cvs. Pakmor and Target) genotypes differing in resistance to iron (Fe) deficiency were grown in nutrient solution under controlled environmental conditions over 50 days to study the relationships between severity of leaf chlorosis, total concentration of Fe, and activities of Fe‐containing enzymes in leaves. The activities of Fe‐containing enzymes ascorbate peroxidase, catalase, and guaiacol peroxidase, and additionaly the activity of glutathione reductase, an enzyme that does not contain Fe, were measured. Plants were supplied with 2 × 10^?7 M (Fe deficient) and 10^?4 M (Fe sufficient) FeEDTA, respectively. Leaf chlorosis appeared more rapidly and severely in Target (Fe deficiency senstive genotype) than Pakmor (Fe deficiency resistant genotype). On day 50, Pakmor had 2‐fold more chlorophyll than Target under Fe deficiency, while at adequate supply of Fe the two genotypes were very similar in chlorophyll concentration. Despite distinct differences in development of leaf chlorosis and chlorophyll concentrations, Pakmor and Target were very similar in concentrations of total Fe under Fe deficiency. In contrast to Fe concentration, activities of Fe‐containing enzymes were closely related to the severity of leaf chlorosis. The Fe‐containing enzymes studied, especially catalase, showed a close relationship with the concentration of chlorophyll and thus differential sensitivity of tomato genotypes to Fe deficiency. Glutathione reductase did not show relationship between Fe deficiency chlorosis and enzyme activity. The results confirm that measurement of Fe‐containing enzymes in leaves is more reliable than the total concentration of Fe for characterization of Fe nutritional status of plants and for assessing genotypical differences in resistance to Fe deficiency. It appears that Fe deficiency‐resistant genotype contains more physiologically available Fe in tissues than the genotype with high sensitivity to Fe deficiency.     

Image changes in chlorophyll fluorescence of cucumber leaves in response to iron deficiency and resupply

Iron (Fe) is an essential element for plants and its deficiency causes decrease not only in the photosynthetic rate but also in the actual photosystem II efficiency at steady‐state photosynthesis. The aim of this work was to determine the effect of Fe deficiency in plants of Cucumis sativus (L.) in two different experimental conditions. In the first experiment, plants were grown with or without Fe for 7 d. After 7 d, Fe‐deficient plants were resupplied with Fe and sampled after 12 h and 48 h. In the second experiment, plants were grown with Fe in the nutrient solution for 3 d and after this period, Fe was withdrawn and plants sampled after 3 and 6 d. Iron and chlorophyll (Chl) concentration and Chl‐fluorescence imaging were measured. In cucumber leaves subjected to Fe deficiency, fluorescence imaging of Chl a evidenced spatial changes on leaf lamina. Following Fe deficiency both after 7 d (Exp. 1) or 6 d (Exp. 2) leaves showed a slight, nonsignificant decrease in F_v/F_m ratio. However Chl‐fluorescence parameters determined in light conditions showed significant changes which indicate an alteration in the photosynthetic process. Surprisingly, the effect of Fe deficiency was more pronounced in leaves of plant of Exp. 2 as compared to those that had grown in complete absence of Fe (Exp. 1). In the latter case down‐regulated mechanisms preserved leaves from irreversible photoinhibition leading to complete recovery when plants were resupplied with the microelement.     

Critical nitrate levels for squash,cucumber and melon plants

Abstract

Squash (Cucurbita pepo), cucumber (Cucumis sativus) and sweet melon (Cucumis dudain) plants were grown in sand culture with N as the variable and were harvested at the early flowering stage. The plants at this time showed a definite gradation of symptoms from severe to no deficiency of N. The tops were separated into leaves and stems. Leaves were separated into young, mature and old and then subdivided respectively into petioles and blades. The petioles were analyzed for NO₃‐N. The critical NO₃‐N concentration for squash, cucumber and melon on a dry basis was 1000, 2000 and 3000 ppm, respectively. A relatively high concentration of NO₃‐N in the nutrient solution decreased the growth of squash and cucumber plants significantly, but had no effect on melon plants. Melon plants can tolerate relatively high concentrations of N0,‐N in the plant tissues, while squash and cucumber cannot.     

Growth and Physiological Changes in Bitter-Gourd Plants Grown with Variable Calcium Supply in Sand Culture

Bitter-gourd (Momordica charantia L.) cv. ‘Jhallari’ plants were grown in refined sand at graded levels of calcium (Ca) supply ranging from acute deficiency (0.02 mM) to excess (8 mM). Apart from the production of characteristic visible symptoms of the respective stresses, deficient (< 4 mM) or excess (8mM) supply of Ca restricted plant biomass and fruit yield. In leaves, the concentration of chlorophyll, Hill reaction activity and the activities of catalase, peroxidase, acid invertase, ATPase, and α-amylase were reduced, but the activity of acid phosphatase was increased by deficiency of Ca. Excess Ca (8 mM) supply significantly reduced the concentration of chlorophyll, Hill reaction activity and the activity of catalase and increased the specific activities of peroxidase, acid invertase, ATPase, α -amylase, and acid phosphatase. Tissue concentration of Ca in leaves and fruits increased with increase in Ca supply from 0.02 to 8 mM. Tissue concentrations in young leaves representing the thresholds of deficiency or toxicity of Ca are found to be 1.12 and 1.98%, respectively. The critical tissue concentration in these leaves suggestive of severe deficiency of Ca is 0.85%.     

缺硼条件下两种不同砧木“纽荷尔”脐橙矿质元素含量变化的比较

采用溶液培养试验,研究了缺硼对两种不同砧木纽荷尔脐橙硼、锌、钙、镁和钾元素含量变化。结果表明,缺硼显著降低了枳壳砧木纽荷尔脐橙体内硼含量而对锌含量影响不大; 相反,缺硼对枳橙砧木脐橙体内硼含量的影响不是很大,而显著降低了其叶片中锌的含量。这可能是缺硼条件下枳壳砧木脐橙容易出现缺硼症状,而枳橙砧木脐橙容易出现缺锌症状的原因之一。与对照相比,缺硼处理的枳壳砧木脐橙叶的钙含量明显增加; 而根的钾含量明显高于枳橙砧木橙根。这些结果与枳壳砧木脐橙对硼更敏感有一定的关系。缺硼对镁含量的影响两种砧木间基本没有差异。     

Foliar Symptomology and Tissue Concentrations of Nutrient‐Deficient Vegetative Strawflower Plants

Abstract

Elemental deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, or boron (N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, or B) were induced in plants of Florabella Pink strawflower [Bracteantha bracteata (Vent.) A. A. Anderberg]. Rooted stem cuttings were planted in 4.87‐L plastic containers and fertilized with a complete modified Hoagland's solution or this solution minus the element that was to be investigated. Plants were harvested for tissue analyses as well as dry weights when initial foliar symptoms were expressed and later under advanced deficiency symptoms. Deficiency symptoms for all treatments were observed within 7 weeks. The most dramatic expression of foliar symptoms occurred with N (chlorotic lower foliage leading to necrotic margins on the mature leaves), Ca (black necrotic spots on the tips of the young leaves), S (uniform chlorosis of young leaves and recently mature leaves), B (thick, leathery, and deformed young leaves), Fe (uniform yellowish‐green chlorosis on the young leaves), and Zn (brownish‐gray necrosis on the tips of the mature leaves). At the initial stage, only Fe‐deficient plants weighed less than the control, whereas K‐, Ca‐, and Mg‐deficient plants had greater dry weights than plants receiving the complete modified Hoagland's solution (control plants). Dry weights of plants treated with solutions not containing N, P, Ca, S, Cu, or Mn were significantly lower when compared with the control plants under an advanced deficiency. Foliar‐tissue concentration data will assist plant‐tissue analysis laboratories in establishing foliar symptom standards for growers.     

不同光强和缺镁胁迫对黄瓜叶片叶绿素荧光特性和活性氧产生的影响

不同光强和镁离子浓度对黄瓜叶片叶绿素荧光特性和活性氧产生的影响研究发现 ,在强光和缺镁胁迫下 ,黄瓜叶片发生了明显的光抑制 ,主要表现为Pn下降 ,叶绿素荧光参数Fv/Fm、Fv/Fo、qP和 qN降低 ;活性氧超氧阴离子产生速率和H2O2以及膜脂过氧化产物MDA增加。这些结果表明 ,缺镁黄瓜叶片在强光下qP和 qN的降低使叶片吸收的过剩光能通过光化学反应途径和非辐射能量途径耗散受阻 ,从而增加了过剩光能所激发的电子用来生成活性氧的比例 ,这在一定程度上可缓解光抑制 ;但其不能被及时清除掉时 ,会加剧光抑制 ,甚至引起光氧化对光合机构造成破坏 ,最终导致叶片的失绿坏死。适当遮荫有利于提高PSII的光化学效率 ,减轻光抑制。     

Calcium nutrition of white rose potato in relation to growth and leaf minerals

Abstract

White Rose potato plants were grown in nutrient solutions containing Ca from 0 to 20 meq/l. After 32 days of growth, 16 plant parts were taken for analysis. The critical level for the immature to the recently matured leaf was determined to be about 0.15% Ca for the petiole and the blade tissues at the breaking point of the transition zone. Ca concentrations of petioles and blades (dry basis) increased with leaf age with the greatest increase in the blade tissues. The petioles of recently matured leaves under severe Ca deficiency were higher in Na, Mg, and PO₄‐P, lower in N0₃‐N and about the same in K concentration in comparison with non‐deficient petioles while the corresponding blades did not differ appreciably. Calcium deficiency has no major effect on the uptake of these minerals since all values were in the adequate range.     

Selecting Rice Genotypes Tolerant to Zinc Deficiency and Sodicity: Differences in Concentration of Major Cations and Sodium/Potassium Ratio in Leaves

Zinc (Zn) deficiency is a major nutritional problem for rice under sodic conditions. Seedlings (35-d old) of 30 rice genotypes were transplanted in pots at pH₂ 9.8 [diethylene triamine penta acetic acid (DTPA) Zn 1.8 ppm] to identify genotypes tolerant to both sodicity and Zn deficiency. Ten genotypes (group A) showed potential to tolerate both the stresses. Sixteen genotypes (group B) were sensitive to Zn deficiency. However, some of the seedlings of group B genotypes were normal (without Zn deficiency symptoms). Four genotypes (group C) were sensitive to sodicity. Leaves and their leaf sheaths were analyzed at 33 d after transplanting for Ca, Mg, K, and Na. Group A genotypes (CSR-88IR15, CSR-89IR14, IR4630-22-2-5-1-2, and Trichi) had significantly less Na concentrations in their leaves and the leaf sheaths compared to group B genotypes (CSR10, CSR23, CSR-88IR1, 89H1-931098, and IR47538-3B-9-3B-1). The concentration of Na was invariably higher in the leaf sheath than its leaf in both the groups, but reverse was true for Ca, Mg, and K. Zinc deficient plants had relatively higher concentrations of Ca and Mg in their leaves and the leaf sheaths than group A. Concentration of K was somewhat better in group A than group B genotypes. Higher Na/K ratio in group B genotypes compared to group A may be attributed to increased concentrations of Na rather than decreases in K concentrations. Further studies are needed to understand the processes associated with differential uptake of Na and K by Zn deficient plants of group B genotypes resulting in higher Na/K ratio compared to group A genotypes.     

Diagnosis of zinc deficiency in peanut (Arachis hypogaea L.) by plant analysis

Abstract

Critical values of zinc (Zn) concentration in young leaves Here established for the diagnosis of Zn deficiency in peanut by examining the relationship of Zn concentration in leaves to shoot dry matter (DM) at two growth stages of plants grown in pots of Zn deficient sand at seven levels of Zn supply (0, 67, 133, 200 267, 533, and 1067 μg Zn/kg soil). Zinc deficient peanut accumulated reddish pigments in stems, petioles and leaf veins in addition to the more common symptoms of Zn deficiency in plants. Zinc concentrations increased with increasing Zn supply in the blades of the youngest fully expanded leaf (YFEL) and in the blades of the leaves immediately older (YFEL+1) and younger (YFEL‐1) than it: they also increased with increasing Zn supply in the petioles of the YFEL+1 and YFEL and in the basal stem internode but their Zn concentrations Here always much lower than those in the blades. Critical Zn concentrations in the blades of the YFEL and YFEL+1 Here 8–10 mg Zn/kg DM at early pegging and mid pod filling: values for YFEL‐1 were similar but more variable. The blade of the YFEL is recommended for diagnosis of Zn deficiency in peanut and 8–10 mg Zn/kg DM as its critical value.     

Copper Stress Affects Metabolism and Reproductive Yield of Chickpea

To observe the effects of copper (Cu) deficiency on growth, metabolism, and reproductive yield of chickpea (Cicer arietinum L.) cv. ‘13.G-256’, plants were grown in refined sand at deficient (0.1 μM) and adequate Cu (1 μM), supplied as copper sulfate (CuSO₄·5H₂O). At d 35–40, at deficient Cu, the growth of plants were depressed and the young leaflets appeared reduced in size, chlorotic, with narrow pointed tips. The primary branches collapsed later, and secondary branches were stunted with reduced number of leaves. The flowering was disturbed, less flowers matured, as a consequence pods and seeds were reduced, malformed and low in productivity, which lowered biomass and economic yield and is accompanied by decrease in Cu concentration in leaves and seeds. The quality of seeds deteriorated at deficient Cu as the concentration of proteins, carbohydrates (sugars and starch), protein nitrogen were lowered, and phenols, non-protein nitrogen, increased. Whereas in leaves, the concentration of carbohydrates (sugars and starch), phenols, and non-protein nitrogen were elevated and protein nitrogen was reduced. Copper deficiency also alleviated the concentration of chlorophyll (a and b) in leaves. At deficient Cu, the activity of antioxidative enzyme viz. peroxidase along with that of acid phosphatase and ribonuclease increased in leaves, seeds and pod wall of chickpea.