Phytosiderophore release in relation to multiple micronutrient metal deficiency in wheat

Phytosiderophore (PS) release, which occurs mainly under iron deficiencies in the representative Poaceae, has been speculated to be a general adaptive response to enhance the acquisition of micronutrient metals. However, it is very common to encounter deficiency of micronutrients other than iron (Fe) in soils and interactions with respect of multi-micronutrient deficiency to effect on PS release are not known. Further, the diurnal rhythm for the release of PS may also be affected under multiple micronutrient deficiency. PS release capacity and PS content of roots and the diurnal rhythm of PS release was measured in selected efficient and inefficient wheat genotypes varied on individual and combined deficiency of Fe, zinc (Zn), copper (Cu) and manganese (Mn) in nutrient solution culture. A nutrient sufficient treatment was also taken as experimental control. Lack of Fe in the nutrient medium caused a significantly higher release of PSs followed by Zn, Mn and Cu in the same order. The diurnal rhythm of PS release was similar in the absence of either of the micronutrients or under their combined deficiency. Micronutrient sufficient control did not release any PS. Fe-use-efficient cultivars produced and released a larger amount of PS and differed from the inefficient cultivars in terms of the PS release but not in the PS biosynthesis in the roots. Thus, indicating that the limitation at the level of release of the PS is responsible for low Fe use efficiency of the Fe deficiency susceptible cultivars. Further, the diurnal variation in the PS release was similar for all the investigated wheat cultivars and did not influence the variation in the Fe use efficiency.     

Nutritional Alleviation of Zinc-Induced Iron Deficiency in Indian Mustard and the Effects on Zinc Phytoremediation

ABSTRACT

Indian mustard (Brassica juncea Czern) is a promising species for the phytoextraction of zinc (Zn), but the effectiveness of this plant can be limited by iron (Fe) deficiency under Zn-contaminated conditions. Our objectives were to determine the effects of root-applied Fe and Zn on plant growth, accumulation of Zn in plant tissues, and development of nutrient deficiencies for B. juncea. In the experiment, B. juncea was supplied 6 levels of iron ethylenediamine dihydroxyphenylacetic acid (Fe-EDDHA; 0.625 to 10.0 mg L^?1) and two levels of Zn (2.0 and 4.0 mg L^?1) for 3 weeks in a solution-culture experiment. Nutrient solution pH decreased with decreasing supply of Fe and increasing supply of Zn in solution, indicating that B. juncea may be an Fe-efficient plant. If plants were supplied 2.0 mg Zn L^?1, plant growth was stimulated by increases in Fe supply, but plant growth was not influenced by Fe treatments if plants were supplied 4.0 mg Zn L^?1. Zinc concentration in roots and shoots was suppressed by increasing levels of Fe in solution. Leaf concentrations of Cu, Mn, and P were suppressed also as Fe supply in solutions increased. Iron additions to the nutrient solution were not effective at increasing the Zn-accumulation potential of B. juncea unless plants were supplied the higher level of Zn in solution culture. Even under these conditions, Fe additions were effective only if supplied at low levels in solution culture (1.25 mg Fe L^?1). Results suggest that Fe fertility has limited potential for enhancing Zn phytoextraction by B. juncea, even if plants suffer a suppression in growth from Fe deficiency.     

Effect of Free Manganese Activity on Yield and Uptake of Micronutrient Cations by Barley and Oat grown in Chelator-buffered Nutrient Solution

The uptake of micronutrient cations in relation to varying activities of Mn²⁺ was studied for barley (Hordeum vulgare L. var. Thule) and oat (Avena sativa L. var. Biri) grown in chelator buffered nutrient solution. Free activities of Mn²⁺ were calculated by using the chemical speciation programme GEOCHEM-PC. Manganese deficient conditions induced elevated concentrations of Zn and Fe in shoots of both species. The corresponding antagonistic relationship between Mn and Cu could only be seen in barley. The observed antagonistic relationships were only valid as long as the plant growth was limited by Mn deficiency. The Mn concentration in both plant species increased significantly with increasing Mn²⁺ activity in the nutrient solution. The concentration of Mn in the shoots of oat was higher than for barley except under severe Mn deficiency where it was found equal for both species. Manganese was accumulated in the roots of barley at high Mn²⁺ activity. The different shoot concentrations of Mn between barley and oat are therefore attributed to the extent of Mn translocation from roots to shoots. Manganese deficiency induced a significant increase in the shoot to root ratio in both species.     

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.     

IRON IS REQUIRED FOR THE INDUCTION OF ROOT FERRIC CHELATE REDUCTASE ACTIVITY IN IRON-DEFICIENT TOMATO

Two mutants of tomato and their corresponding wild-type genotypes, Tfer/TFER and chloronerva/Bonner Beste, were grown in nutrient solution under conditions leading to iron (Fe) deficiency. Iron deficiency caused decreases in growth, leaf chlorosis, and changes in the morphology of roots. Ferric chelate reductase activities of whole roots were generally lower in Fe-deficient plants than in control, Fe-sufficient plants. Plants grown for 7 days without Fe, however, had transient increases in whole root ferric chelate reductase activity after the addition of small amounts of Fe (2 μM) to the nutrient solution. Also, adding sequential 0.5 μM Fe pulses to the nutrient solution led to high whole root ferric chelate reductase activities. Similar results were obtained with a protocol using excised root tips instead of whole root systems to measure ferric chelate reductase activities. The protocol using root tips generally gave higher ferric chelate reductase rates than the method using whole roots, due to the localized expression of the enzyme in the distal root zones.     

Influence of ferredoxin levels on nitrate reductase activity in iron deficient lemon leaves

The relationship between nitrate reductase activity and ferredoxin levels in lemon tree leaves was studied. The experiments were carried out on leaves from full‐nutrient sufficient trees as the reference, and on leaves from trees with several nutritional stresses, mainly iron chlorosis from trees growing under Fe‐stressed conditions.

Iron deficiency reduced leaf ferredoxin concentration and consequently decreased nitrate reductase activity. Fe(II) infiltration treatments of intact leaves, as well as several incubation assays, permit to deduce the dependence of the enzymatic nitrate reduction of the leaf ferredoxin levels.     

Enhanced Mn accumulation by snapbean cultivars under FE stress

Iron deficiency in dicots is accompanied by an increased potential for Fe uptake and translocation. The mechanisms responsible for these changes in metabolism (Fe‐stress response) provide for the adaptation of Fe‐efficient genotypes to conditions which limit the availability of Fe. Previous studies indicated that when Fe‐stress response is initiated, the uptake of Mn, as well as Fe, is enhanced in Fe efficient species such as sunflower. The present study was conducted to determine the relationship between Fe‐stress response and Mn uptake in snapbean (Phaseolus vulgaris L., cvs. Bush Blue Lake 290, Bush Blue Lake 274). The plants were grown in complete nutrient solutions containing 0.02 to 0.52 mg L^‐1 Mn, at acid or alkaline pH. Iron stress was induced with 0.22 mg l‐¹ Fe(EDDHA) (molar ratio 1:1 or 1:2), high P (14.3 mg L‐¹) and excess CaCO_3. Bush Blue Lake 290 ('BBL 290') was more sensitive than Bush Blue Lake 274 ('BBL 274') to Mn toxicity in acid (pH 5.2) nutrient solutions with adequate Fe. Under alkaline conditions, Mn accumulation by ‘BBL 290’ snapbean was increased dramatically with Fe stress, while a moderate Increase was found for ‘BBL 274’. Foliar symptoms of Mn toxicity, observed on Fe stressed ‘BBL 290’, increased in severity at higher Mn (0.06 to 0.26 mg L^‐1 ) concentrations. It was concluded that the magnitude of the enhanced Mn uptake was related to the intensity of Fe stress response as well as the cultivar sensitivity to Mn.     

Physiological responses of grapevine callus cultures to iron deficiency

Grapevine is considered a ‘Strategy I’ plant because it performs some peculiar biochemical and physiological responses when grown under iron (Fe) deficiency stress conditions. Callus cultures were started from leaf and internode cuts of micropropagated plantlets of two grapevine genotypes well known for their Fe‐chlorosis characteristic: Vitis riparia a very susceptible genotype and Vitis berlandieri a resistant one. Modification of NADH: ferric (Fe³⁺) reductase activity was spectrophotometrically evaluated by following the formation of the complex ferrous (Fe²⁺)‐(BPDS)₃, while the malic and citric acid production were determined in callus cultures grown both in the presence (+Fe) and absence (‐Fe) of Fe. Moreover, a microsomal fraction was isolated from the calli to evaluate the H⁺‐ATPase and the Fe³⁺‐EDTA reductase activities. As expected, calli of the Fe‐efficient genotype (V. berlandieri) was able to enhance Fe³⁺‐EDTA reductase activity when growing under Fe deficiency while the Fe‐chlorosis susceptible V. riparia could not or did it with lower efficiency. Therefore, the H⁺‐ATPase assay showed a higher enzymatic activity in the microsomal fraction isolated from Vitis berlandieri grown without Fe with respect to its control (+Fe). Organic acid determination gave quite contradictory results, specially regarding malic acid which, under our study conditions, seemed not to be linked with the strategies of response to Fe deficiency.     

Rootstock Effect on Nutrient Concentration of Sweet Cherry Leaves

The present investigation aimed to study the leaf mineral composition of sweet cherry trees on different rootstocks, since the literature data on uptake efficiency of different rootstocks is inconsistent. Results confirmed the different uptake efficiency of rootstocks. The efficiency of ‘GiSelA 6’ root is emphasized in uptake and supply of leaves with nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), boron (B), and manganese (Mn), but trees on this rootstock tend to develop calcium (Ca), magnesium (Mg), and copper (Cu) deficiencies. The Prunus mahaleb rootstocks on calcareous sandy soil are efficient supplier of N, P, K, Ca, Mg, Fe, and Cu, but this root tends to develop Zn, B, and Mn deficiencies. Prunus avium seedling as rootstock proved to be less efficient in supply of leaves by N, P, K, Ca, and Cu. Prunus fruticosa ‘Prob’ root showed tendency in developing several leaf nutrient deficiencies. The applied fertilizer program led to low nutrient levels or even deficiency symptoms in leaves.     

EFFECT OF IRON DEFICIENCY ON ROOT FERRIC CHELATE REDUCTASE,PROTON EXTRUSION,BIOMASS PRODUCTION AND MINERAL ABSORPTION OF CITRUS ROOT STOCK ORANGE JASMINE (MURRAYA EXOTICA L.)

Three-week iron (Fe) deficiency stress experiments were conducted using two citrus root stocks, Fe-deficiency tolerant Orange Jasmine (OJ, Murraya exotica L.) and the sensitive Flying Dragon [FD, Poncirus trifoliata var. monstrosa (T. Ito) Swingle]. Root ferric chelate reductase activity and proton extrusion increased in OJ between 12 and 18 d of stress, whereas there was no change in FD. Dry weight of OJ roots increased in contrast to FD which decreased. The Mn content in OJ remained the same even under Fe stress. Zn content in OJ roots doubled while that of FD increased 4-folds. The shoot/root Fe accumulation ratio increased in OJ while it decreased in FD. OJ apparently has mechanisms for increasing root biomass, controlling Fe reutilization and regulating manganese (Mn) and zinc (Zn) absorption in response to Fe deficiency. These mechanisms could help maintain homeostasis under heavy metal stress, which would be useful for improved growth of economically important citrus species.     

Effect of zinc deficiency in wheat on the release of zinc and iron mobilizing root exudates

The effect of Zn deficiency in wheat (Triticum aestivum L. cv. Ares) on the release of Zn mobilizing root exudates was studied in nutrient solution. Compared to Zn sufficient plants, Zn deficient plants had higher root and lower shoot dry weights. After visual Zn deficiency symptoms in leaves appeared (15–17 day old plants) there was a severalfold increase in the release of root exudates efficient at mobilizing Zn from either a selective cation exchanger (Zn-chelite) or a calcareous soil. The release of these root exudates by Zn deficient plants followed a distinct diurnal rhythm with a maximum between 2 and 8 h after the onset of light. Re-supply of Zn to deficient plants depressed the release of Zn mobilizing root exudates within 12 h to about 50%-, and after 72 h to the level of the control plants (Zn sufficient plants). The root exudates of Zn deficient wheat plants were equally effective at mobilizing Fe from freshly precipitated Fe^III hydroxide as Zn from Zn-chelite. Furthermore, root exudates from Fe deficient wheat plants mobilized Zn from Zn-chelite, as well as Fe from Fe^III hydroxide. Purification of the root exudates and identification by HPLC indicated that under Zn as well as under Fe deficiency, wheat roots of the cv. Ares released the phytosiderophore 2′-deoxymugineic acid. Additional experiments with barley (Hordeum vulgare L. cv. Europa) showed that in this species another phytosiderophore (epi-3-hydroxymugineic acid) was released under both Zn and Fe deficiencies. These results demonstrate that the enhanced release of phytosiderophores by roots of grasses is not a response mechanism specific for Fe deficiency, but also occurs under Zn deficiency. The ecological relevance of enhanced release of phytosiderophore also under Zn deficiency is discussed.     

Iron deficiency stress responses amongst citrus rootstocks

Seedlings of citrus rootstocks differing in lime tolerance were grown in nutrient solution with and without Fe. Proton efflux, release of phenolic compounds and Fe reducing substances and root-mediated reduction of Fe^III in FeEDTA and freshly precipitated Fe(OH)₃ in response to Fe deficiency were determined. Sweet orange, Carrizo citrange and trifoliate orange, the three least tolerant rootstocks used in the study, did not decrease nutrient solution pH in response to Fe deficiency. The more lime tolerant rootstocks, rough lemon, Cleopatra mandarin and sour orange, did decrease nutrient solution pH. But in CaSO₄ solution only sour orange increased H⁺ efflux significantly under Fe deficiency. In response to Fe deficiency, the release of phenolic compounds was increased significantly in rough lemon and Cleopatra mandarin seedlings, while the release of reducing substances was increased significantly in rough lemon, sour orange and trifoliate orange. Rough lemon was the only rootstock to respond to Fe deficiency with an increase in root-mediated reduction of chelated Fe^III at pH 6.5. At pH 8.0, both Fe-deficient rough lemon and Cleopatra mandarin roots reduced higher amounts of Fe^III from freshly precipitated Fe(OH)₃ than Fe-sufficient seedlings. Iron reduction by detached roots of Fe-deficient and Fe-sufficient rough lemon did not follow Michaelis-Menten kinetics at high substrate concentrations. Rates of Fe reduction at low substrate concentrations were inconsistent with the existence of an inducible ferric reductase in response to Fe deficiency.     

Iron deficiency responses in roots of kiwi

Many dicotyledonous species respond to iron (Fe) deficiency by morphological and physiological changes at root level, which are usually defined as Strategy I. Particularly, these latter modifications include a higher acidification of the external medium and the induction of a high root Fe reductase activity. The aim of this work was to investigate the response of kiwi (Actinidia deliciosa cv. Hayward) plants, which often exhibit Fe chlorosis in the field, to Fe deficiency. Actinidia kept for two weeks in nutrient solution without Fe showed visual deficiency symptoms (leaf chlorosis). Moreover, upon prolonged micronutrient shortage shoot, and to a lesser extent, root dry weight accumulation was greatly impaired. Roots of Fe‐deficient Actinidia showed an increased capacity of net proton extrusion and higher ferric ethylenediaminetetraacetate [Fe(III)EDTA] reductase activity as compared to plants grown in the presence of 10 μM Fe(III)EDTA. Localization of the increased acidification and reductase capacity by means of agar‐technique revealed that these activities are both present in the sub‐apical region of the roots. Re‐supply of Fe after two weeks partially reversed the tendency of the roots to acidify the nutrient solution and to reduce Fe(III)EDTA.     

Overcoming Fe deficiency in guava (Psidium guajava L.) by co-situs application of controlled release fertilizers

Abstract

Among micronutrient deficiencies, Fe deficiency is the most difficult nutritional disorder to prevent in the fruits of trees growing on calcareous soils. In this study, a pot experiment was carried out to evaluate the potential of co-situs application of controlled release fertilizers (CRF) in alleviating Fe deficiency and improving the growth of fruit trees growing on calcareous soil (pH 9.3). Guava (Psidium guajava L.) seedlings were used as test plants because of their sensitivity to Fe deficiency. Treatments consisted of the following: (1) broadcast application of readily soluble Fe, Zn, Cu, B and Mn fertilizers (Control) or (2) co-situs application of CRF containing N, P, K, Mg, Fe, Zn, B, Cu and Mn (Co-situs). For the Control treatment, CRF containing only N, P and K was used. Both treatments received the same amount of all nutrients. Plants were more chlorotic in young leaves under the Control treatment and the Fe content of young leaves was significantly (least significant difference [LSD_0.05]) higher under the Co-situs treatment. Dry matter production of shoots under the Co-situs treatment was 5.2-fold higher than under the Control treatment, and the total accumulations of macro and micronutrients were much higher under the Co-situs treatment than the Control treatment. Total accumulations of N, P, K, Ca and Mg were 5.0, 4.1, 9.6, 3.2 and 2.2-fold higher, respectively, under the Co-situs treatment compared with the Control treatment, and Fe, Zn, Cu and Mn accumulations were 3.2, 4.1, 6.0 and 3.7-fold higher, respectively. Iron deficiency in guava seedlings was successfully alleviated by the co-situs application of controlled fertilizer, proving the high potential of this method in alleviating Fe deficiency in fruit trees growing on calcareous soils.     

INFLUENCE OF ELEVATED PHOSPHORUS LEVELS IN NUTRIENT SOLUTION ON MICRONUTRIENT UPTAKE AND DEFICIENCY SYMPTOM DEVELOPMENT IN STRAWBERRY CULTURED WITH FERTIGATION SYSTEM

The relationship between the total amount of micronutrients absorbed by the above-ground plant tissue and the occurrence of visible micronutrient deficiency symptoms in two strawberry cultivars as influenced by elevated phosphorus (P) levels in fertigation solution was investigated. The plants were cultured with a fertilizer solution containing 0, 0.5, 1, 2, 4, or 6 mM P and tissue nutrient content were determined at 120 days after transplanting. Young leaves of the plants grown with nutrient solution P levels higher than 4 mM and 2 mM, respectively, in ‘Keumhyang’ and ‘Seonhong’, developed interveinal chlorosis. Tissue concentrations (mg·kg^?1 dry weight) of metallic micronutrients [iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn)] in both cultivars did not decrease, but the total amount absorbed by the aboveground plant tissue decreased in the treatments in which nutrient deficiencies were observed. These results indicate that total amount of micronutrients is a better indicator of P-induced micronutrient deficiency.     

Physiological and biochemical changes in young maize plants under iron deficiency: 2. Catalase,peroxidase, and nitrate reductase activities in leaves

Young maize plants, grown hydroponically, were supplied with different amounts (7.5,0.75,0.15, 0.075, and 0 mg Fe/L) of iron (Fe). At 14, 21, and 28 days, in vitro activities of catalase, peroxidase and nitrate reductase in leaves were determined. Strong and complete Fe deficiency resulted in decreased enzyme activities. Under moderate Fe deficiency—often a restoration of the normal activity after an initial reduction—was observed. The rapidity and the degree of reaction to Fe deficiency depended on the enzyme. The ratio peroxydase/catalase activity can not be applied as a reliable tool for diagnosis of Fe deficiency.     

EFFECT OF PETUNIA STOCK PLANT NUTRITIONAL STATUS ON FERTILIZER RESPONSE DURING PROPAGATION

Fertilization strategies during stock plant and cutting production are linked in terms of cutting nutrient levels and quality. Objectives were to evaluate (1) the effect of stock plant nutrition on tissue nutrient concentration and growth during vegetative propagation and (2) response to fertilizer during propagation for cuttings with 4 different initial tissue nutrient concentrations. ‘Supertunia Royal Velvet’ petunia stock plants were grown under constant fertigation of 0, 50, 100 or 200 mg nitrogen (N)^.L^?1 for 21 days. The 200 mg N^.L^?1 solution contained 150 nitrate (NO₃-N), 50 ammonium (NH₄-N), 24 phosphorus (P), 166 potassium (K), 40 calcium (Ca), 20 magnesium (Mg), 0.7 sulfur (S), 1.0 iron (Fe), 0.5 manganese (Mn), 0.5 zinc (Zn), 0.24 copper (Cu), 0.24 boron (B), and 0.1 molybdenum (Mo). Providing a complete fertilizer during propagation of petunia, beginning immediately after sticking of cuttings, reduces the risk of nutrient deficiency. Particularly in situations where fertilizer is not applied early during propagation, stock plants should be managed to ensure unrooted cuttings have adequate nutrient reserves.     

Phytosiderophore release from manganese‐induced iron deficiency in barley

An experiment was conducted in the phytotron with barley (Hordeum vulgare L. cv. Minorimugi) grown in nutrient solution to compare iron (Fe) deficiency caused by the lack of Fe with manganese (Mn)‐induced Fe deficiency. Dark brown spots on older leaves and stems, and interveinal chlorosis on younger leaves were common symptoms of plants grown in either Mn‐toxic or Fe‐deficient treatments. Dry matter yield was affected similarly by Fe deficiency and Mn toxicity. The Mn toxicity significantly decreased the translocation of Fe from roots to shoots, caused root browning, and inhibited Fe absorption. The rate of Fe translocated from roots to shoots in the 25.0 μM Mn (toxic) treatment was similar to the Fe‐deficient treatment. Manganese toxicity, based on the release of phytosiderophore (PS) from roots, decreased from 25.0>250>2.50 uM Mn. The highest release of PS from roots occurred 7 and 14 days after transplanting (DAT) to Mn‐toxic and Fe‐deficient treatments, respectively; but was always higher in the Fe‐deficient treatment than the Mn‐toxic treatments. The release of PS from roots decreased gradually with plant age and with severity of the Mn toxicity symptoms. The PS content in roots followed the PS release pattern.     

Growth and nutrition of Holcus lanatus in bauxite residue amended with combinations of spent mushroom compost and gypsum

Bauxite residues are very slow to naturally vegetate due to nutrient deficiency and high sodicity. In order to test the effectiveness of amendments at promoting revegetation, bauxite residue was amended with varying rates of compost to increase fertility (0, 60, 80 and 120 t ha⁻¹) and gypsum to reduce sodicity (0, 40 and 90 t ha⁻¹). Amended residue was sown with Holcus lanatus, a perennial grass. Following a 1‐year growth period, substrate properties, plant performance and plant nutrient uptake were assessed. Compost application substantially increased substrate N, P, K and Mn concentrations, while gypsum application greatly reduced sodicity and improved nutrient uptake for Mn and P. Compost amendment was essential for sustainable plant growth. Foliar deficiencies in N, P and Mg may persist with lower compost application rates, requiring the addition of supplemental fertiliser for healthy plant growth. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of humic acid and Ca(NO3)2 on nutrient contents in pepper (Capsicum annuum) seedling under salt stress

This study was carried out in order to determine the effects of calcium nitrate (Ca(NO₃)₂) and humic acid (HA) applications on nutrient uptake of pepper seedling under salt stress in a plant growth room. Before sowing Demre variety of pepper seeds, 60?mM NaCI was added to each 300?cm³ pot. The experiment was ended at eighth week after the sowing. Applications of HA significantly affected K, Ca, Fe, Mn, Zn (p?p?3)₂ applications did not show a significant effect on Fe and Cu contents of pepper seedling. However, Ca(NO₃)₂ applications significantly affected N and P contents (p?<.05) and K, Ca, Mn, and Zn contents (p?相似文献