Effect of iron supply and nitrogen form on growth,nutritional status and ferric reducing activity of spinach in nutrient solution culture

This study was carried out in order to give some information that could improve spinach nutritional status and productivity. In this paper, the effect of two N forms (N was added either as 100% nitrate or as 80% nitrate and 20% ammonium) and three Fe levels (0 μM Fe; 20 μM FeEDDHA; 3 μM FeEDDHA + 10 mM NaHCO₃) on the growth, chlorosis symptoms and shoot nutrient element accumulation was studied in spinach plants (var. Viroflay), grown in hydroponics; six treatments and three harvests (at about 20 days interval each, until plants reached their commercial size) were applied in total. The results indicated that under conditions of Fe sufficiency (20 μM Fe), mixed N nutrition induced higher production of dry matter as well as improved Fe, Mn and Zn plant nutritional status. In plants grown under Fe deprivation (0 μM Fe), shoot Fe concentration was not significantly affected by the N form until the end of the experiment despite mixed N nutrition induced higher dry matter production up to harvest 2; plants grown under Fe deprivation and with mixed N nutrition presented also higher shoot Mn and Zn concentration. Under conditions of high concentration of bicarbonates and low level of Fe (3 μM Fe + 10 mM NaHCO₃), the N form had not a significant influence on total dry matter production whereas shoot Fe and Mn accumulation in 100% NO₃-fed plants was found to be significantly reduced compared to mixed N nutrition; regardless of the N form, those plants presented the least dry matter production, highest intensity of leaf chlorosis as well as highest root ferric reducing activity compared to plants grown under Fe deprivation.     

Comparison of three pea cultivars (Pisum sativum) regarding their responses to direct and bicarbonate-induced iron deficiency

The aim of this work was to explore leaf characteristics underlining the difference in the sensitivity of pea cultivars (cv. Kelvedon, Douce and Lincoln) to Fe deficiency. Plants were grown in a greenhouse under controlled conditions in continuously aerated solution. Three treatments were used: 30 μM Fe (+Fe), 0 μM Fe (−Fe); direct deficiency and 30 μM Fe + 10 mM NaHCO₃ (+Fe+Bic); indirect deficiency for 12 days. Growth parameters, iron status, potassium content, chlorophyll fluorescence and photosynthetic capacity were studied. Our results showed that Fe deficiency led to a significant decrease of chlorophyll index (SPAD readings) and bivalent iron content in all Pisum sativum cultivars. The lower reduction was observed in Fe-deficient plants of Kelvedon and Douce. In addition, shoot length and whole plant dry weight were not affected by Fe deficiency in the latter cultivars. Both tolerant cultivars showed higher accumulation of potassium content in their leaves compared with the sensitive one. Moreover, both chlorophyll fluorescence ratios (F_v/F_m and F_v/F₀) were significantly decreased in all cultivars under both Fe deficiency treatments. The photosynthetic electron transport activity was reduced in the sensitive cultivar, especially in the absence of iron. The adverse effect of bicarbonate-induced Fe deficiency on the above mentioned parameters were more pronounced than that of the direct one. The capacity of both tolerant cultivars to preserve adequate chlorophyll synthesis, photosynthetic capacity and plant growth under iron-limiting conditions is related to the suitable nutrition of their leaves in ferrous iron, due to (at least partially) their higher potassium content.     

Foliar application of chlorocholine chloride improves leaf mineral nutrition,antioxidant enzyme activity,and tuber yield of potato (Solanum tuberosum L.)

In southern China, potatoes (Solanum tuberosum L.) are grown in the late season and the crops are often subjected to low temperature stress particularly during the tuber bulking stage. Exogenous chlorocholine chloride (CCC) treatment has been found to improve crop performance under suboptimal growth conditions; however, the physiological mechanisms underlying the beneficial effects have not been fully understood. The objective of this study was to investigate the effects of CCC treatment on mineral nutrition, antioxidant enzyme system, and tuber yield of potato (cv. Zhongshu 3) under field conditions. The plants were foliar sprayed twice with 1.5, 2.0 and 2.5 g l⁻¹ CCC at 24 and 28 days after emergence (DAE), respectively; and plants without CCC treatment were serviced as control. Leaf samples were collected on 56 DAE for determination of mineral nutrition contents and antioxidant enzyme activity. Results showed that 1.5 and 2.0 g l⁻¹ CCC treatments significantly increased the contents of P, K, Ca, Mg, Fe, Mn, Zn and Cu in potato leaves. These treatments also increased superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT) activities in the leaves. A positive linear relationship was found between SOD activity and the content of Fe + Mn + Zn + Cu. Tuber yield was significantly increased by CCC treatment. It is concluded that treatment with certain concentration of CCC (e.g. 1.5–2.0 g l⁻¹) improves mineral nutrition and SOD, POD and CAT activities in potato leaves; which might have contributed to the higher tuber yield of the crop grown under suboptimal conditions.     

Effects of exogenous salicylic acid and nitric oxide on lipid peroxidation and antioxidant enzyme activities in leaves of Brassica napus L. under nickel stress

The effects of nickel in combination with salicylic acid (SA) and sodium nitroprusside (SNP), a donor of nitric oxide (NO) on 21-day-old canola plants were evaluated. Exposure to 0.5 mM NiCl₂·6H₂O for 10 days resulted in toxicity symptoms such as chlorosis and necrosis at leaves. Addition of 0.2 mM SA or 0.2 mM SNP slightly reduced the toxic effects of nickel. After application of both SA and NO, these symptoms considerably decreased. Treatment with Ni resulted in a decrease in dry weight of roots and shoots and chlorophyll content of leaves. In Ni-treated plants, level of lipoxygenase activity and malondialdehyde (MDA), H₂O₂ and proline contents significantly increased, while the activities of the antioxidant enzymes such as catalase, guaiacol peroxidase and ascorbate peroxidase decreased in leaves. The results indicated that Ni caused an oxidative stress in canola plants. The Ni-stressed plants exposed to SA or NO, especially to SA + NO, exhibited an improved growth as compared to Ni-treated plants. SA or NO, especially both together considerably reduced root-to-shoot translocation of Ni and increased the activities of the antioxidant enzymes in leaves of Ni-stressed plants. Interaction of SA and NO improved the chlorophyll content and decreased the level of lipid peroxidation, H₂O₂ and proline accumulation in leaves. These results suggest that SA or NO in particular their combination counteract the negative effects of Ni on canola plants.     

半根供铁对苹果砧木幼苗生长的影响

利用分根技术在水培条件下研究了半根供铁对苹果砧木幼苗生长的影响。结果表明,一半根系供铁不仅未影响植株对铁营养的需求,甚至在处理初期植株的铁吸收总量和铁吸收速率还略有提高。一半根系供铁苹果砧木小金海堂和山定子叶片活性铁质量分数均未降低,而且与对照相比无叶片黄化的现象。因此,通过半根供铁的方式来改善苹果砧木幼苗的生长,为进一步研究砧木缺铁适应性反应的调控部位打下基础,也为今后缺铁的矫正和提高铁素利用效率提供了一条新的思路。     

Nickel supplementation effect on the growth,urease activity and urea and nitrate concentrations in lettuce supplied with different nitrogen sources

Effect of nickel (Ni) in the nutrient solution on yield, N metabolism, and nitrate content of leafy vegetables is poorly understood. The aim of this nutrient solution culture experiment was to investigate the effects of Ni supplementation on the nitrogen (N) metabolism and growth of lettuce (Lactuca sativa L. cv. Baker) with either urea or nitrate as the N source. Nickel supplement at 0.04 μM reduced urea toxicity to the urea-fed plants. Addition of Ni to the nutrient solution significantly increased the leaves and root growth of the urea-fed lettuce plants while it increased the growth of lettuce plants fed with nitrate only at N level of 20 mM. At N level of 20 mM, the leaves fresh weight of the urea-fed plants promoted by Ni supplement was comparable with the nitrate-fed plants untreated with Ni. Nickel supplementation increased the leaf total N concentrations in the urea-fed plants, although the nitrate-fed plants accumulated greater N in their leaves compared with urea treated plants at without Ni treatment. Nickel addition decreased the concentrations of leaf urea-N in the urea-fed plants and NO₃-N in the nitrate-fed plants. Nickel addition enhanced urease activity in the leaves of urea-fed plants. The results indicated Ni supplementation enhances the growth of the urea-fed lettuce plants while it has role in decreasing leaf nitrate concentration and thus, improving the health quality of the nitrate-fed plants.     

Response of four olive (Olea europaea L.) cultivars to six B concentrations: Growth performance,nutrient status and gas exchange parameters

A greenhouse experiment was conducted to study the effects of boron (B) on growth, nutrient status, B distribution and gas exchange parameters of olive plants (Olea europaea L.). One-year-old own-rooted olive plants of the Greek cultivars Megaritiki, Chondrolia Chalkidikis, Amfissis and Kalamon were grown in a sand–perlite medium and irrigated with nutrient solutions containing: 0.27, 0.5, 1, 2.5, 5 and 10 mg L⁻¹ B (0.27 and 10 mg L⁻¹ were considered as control and excess B treatment, respectively). After culturing for 185 days, leaves and stems (from basal and apical part of the shoots) and roots were separately sampled. Our results showed that the final number of leaves per plant was negatively correlated with B concentration in the nutrient solution. Furthermore, in B10.0 treatment, ‘Megaritiki’ had decreased length and number of lateral stems, ‘Chondrolia Chalkidikis’ and ‘Amfissis’ showed decreased length of lateral stems and ‘Kalamon’ decreased length of lateral stems and plant height. In general, dry weight of stems and leaves was not significantly correlated with B concentration in the nutrient solution. B concentration in leaves and stems was linearly correlated with B supply. A linear correlation existed between B concentration of the nutrient solution and that of leaves and stems. At the end of the experiment, B levels in the leaves and stems of B0.27 and B0.5 treatments did not differ significantly. In general, the increase of B concentration in the nutrient solution, negatively affected the nitrogen (N) concentration of leaves and stems while phosphorus (P) and iron (Fe) concentrations were not affected. Furthermore, potassium (K) and calcium (Ca) concentration in stems of plants supplied with 10 mg L⁻¹ B was decreased. In addition, high B supply resulted in increased magnesium (Mg) and manganese (Mn) concentrations in ‘Chondrolia Chalkidikis’ and ‘Amfissis’ and in the decrease of zinc (Zn) concentrations, in all plants. A significant decline in photosynthetic rate at the end of the experiment was observed in the B5.0 treatment regardless of cultivar.     

Mineral nutrition of jojoba explants in vitro under sodium chloride salinity

Jojoba (Simmondsia chinensis (Link) Schneider) explants were cultured in vitro on a basal medium supplemented with sodium chloride up to 169 mM during the proliferation stage. At the second and third month of salinity stress, the mineral nutrition (macro- and micro-elements) of the explants was assessed. Explants accumulated significant amounts of sodium and chloride (jojoba is an ‘includer’) while potassium, manganese, phosphorus and nitrate concentration was reduced. The concentration of the other elements did not exhibit significant changes. Each level of salinity stress affected the nutrient status of the explants distinctively. Jojoba explants tolerate salinity up to a level of sodium chloride concentration (113 mM), without showing any stress symptoms. Above this level, the salinity stress impact was observed as succulence and chlorosis of leaves and shoots.     

Putting back what we take out,but how much?: Phosphorus and nitrogen additions to farmed Leucadendron ‘Safari Sunset’ and Leucospermum ‘Succession’ (Proteaceae)

Proteaceae are adapted to low-nutrient soils in the various regions where they occur. However, harvesting of flowering stems for the cut-flower industry must eventually cause soil nutrient depletion sufficient to reduce yields. Different N forms, and N and P concentrations were supplied to two Proteaceae cultivars (Leucadendron ‘Safari Sunset’ and Leucospermum ‘Succession’) in a controlled fertigation experiment, and appropriate concentrations for maximum growth with minimum nutrient accumulation or loss were determined. Small additions of N (0.025–0.1 mM) significantly improved growth of both cultivars growing on Strandveld sandy soil. Larger additions of N (up to 2 mM N) resulted in poor growth (both cultivars) and N accumulation in the soil (Safari Sunset). Small additions of P (<10 μM) significantly improved growth of both cultivars and resulted in no accumulation or loss of P in the soil. Larger additions of P (up to 500 μM) resulted in poor growth, P toxicity symptoms and P leaching from the upper soil layers. Best N forms in descending order of both plant visual appearance and vegetative yield were: urea ≥ ammonium nitrate > ammonium sulphate > calcium nitrate. Phosphorus toxicity symptoms were associated with increased concentrations of leaf P, Ca and Fe. Under conditions of maximum growth (10 μM P and 0.1 mM N) Safari Sunset removed 18 ± 0.6 g N, 1.5 ± 0.1 g P, 5.3 ± 0.6 g K and Succession removed 5.5 ± 0.2 g N, 0.3 ± 0.02 g P, 3.1 ± 0.5 g K over 6 months. At maximum growth, plants acquired more N and P amounts than were supplied, but supplying higher N and P concentrations adversely affected growth. Thus, a more complex or slow-release form of N and P than urea and soluble phosphate, respectively, may provide enough N and P to replace losses from the farm soil at the low concentrations required for proteas.     

The effect of nitrate and plant size on nitrate uptake and in vitro nitrate reductase activity in strawberry (Fragaria × ananassa cv. Selva)

Nitrogen plays a major role in the growth and yield of strawberry. For optimizing nitrogen fertilizer application, it is necessary to understand the response of strawberry to nitrogen supply. The objective of this study was to determine the effect of nitrate supply and plant size on strawberry nitrate uptake and nitrate reductase activity (NRA). Strawberry plants cv. Selva were grown under growth chamber conditions in nutrient solutions containing 0, 0.1, 0.25, 0.7 or 4 mM nitrate. Cumulative nitrate uptake increased with the increase in nitrate supply. Increasing nitrate concentrations from 0 to 0.25 mM decreased leaf NRA; however, further increases to 4 mM nitrate restored NRA to activities observed at 0 mM nitrate. The activity of NADH- and NADPH-dependent NR was similar at every external nitrate concentration. Activity of NR was greater in the smallest plants and decreased as plant size increased. However, increasing external nitrate concentration increased nitrate uptake, but had not the same effect on nitrate reductase activity, showing that NRA and nitrate uptake are not necessarily correlated.     

铁肥品种和施肥方式对黄化苹果树复绿和铁含量的影响

铁胁迫致苹果黄叶时,对根系输铁液能在较短时间内提高叶片叶绿素和铁的含量,从而达到复绿的效果。在Ｆｅ Ｃｉｔｒｉｃ ａｃｉｄ、Ｆｅ ＥＤＴＡ 和Ｆｅ Ｎ 三种铁肥中,Ｆｅ Ｎ 是适宜根系输液的铁肥品种,主干强力高压注射铁肥复绿较慢,叶面喷布效果不显著。     

Mobilization of nitrogen in the olive bearing shoots after foliar application of urea

Mature ‘on’ and ‘off’ ‘Manzanillo’ olives trees with three healthy branches of 10–12 cm in diameter were selected to determine changes in nitrogen levels in the bearing shoots after foliar application of urea. Each selected branch of each tree received one of the following treatments: (i) control without urea application; (ii) foliar application of urea to all the current-season leaves; and (iii) foliar application of urea to all the one-year-old leaves. Urea was applied in May, four days after full bloom in the ‘on’ year trees. Each treated leaf was immersed in a test tube containing a 4% urea solution and 0.1% Tween 20 for 5 s. Bearing shoots, composed of both one-year stems and leaves and current-season stems and leaves, were collected at intervals from the beginning of the experiment until 64 days after urea application. Nitrogen was determined in stems and leaves from each part of the bearing shoot, and in fruits during the ‘on’ year. Nitrogen uptake from the leaves was rapidly mobilized from the older to the current-season leaves of the bearing shoot, and thereafter to other storage organs of the tree or to the fruit, which is the largest nitrogen sink in the bearing shoot. No translocation of nitrogen from the current-season leaves to older leaves was observed. The rapid translocation of nitrogen from the younger leaves to other storage organs of the tree could explain the insensitivity of leaf analysis to detect excess nitrogen, since mature leaves from current-season shoots must be sampled to determine the nutritional status of the tree. The failure of leaf analysis to detect excess nitrogen may be a cause of nitrogen over-fertilization in olive orchards.     

‘南丰蜜橘’缺铁、锰、锌的症状及其光合特性和营养状况研究

为明确‘南丰蜜橘’缺Fe、Mn、Zn元素的症状,揭示其对光合特性和营养状况的影响,以2年生枳砧‘南丰蜜橘’幼苗为试验材料,进行砂培盆栽缺素试验。结果表明,缺Fe处理后,‘南丰蜜橘’初级新叶呈现黄绿化,但叶脉仍为绿色,次级新叶淡黄色,新出小叶甚至为白色,叶脉也呈白色,有的次级新梢茎尖枯死,且较正常新叶变得小而狭长;缺Mn处理后,初级新叶叶脉间出现肋骨状突起,突起部位黄化;次级新叶叶脉呈绿色网状,脉间失绿,有的叶片出现褐色斑点;缺Zn处理下,初级新叶出现黄色斑点,后期斑点连成片呈现不规则的黄化区域,次级新叶则出现黄化失绿,有大量黄化斑点,同时伴有小叶簇生症状,且次级新叶显著变小,长宽比显著上升。缺Fe、Mn和Zn均显著降低了‘南丰蜜橘’初级新叶的叶绿素含量,但各处理的降幅存在显著差异(缺Fe缺Mn缺Zn)。缺Fe处理下的老叶和初级新叶,以及缺Mn和Zn处理下的初级新叶叶片光合作用均受到显著抑制。缺Fe、Mn和Zn处理后,除显著降低植株各部位Fe、Mn和Zn的含量,对其他矿质元素的含量也有不同程度的影响。     

苹果不同施肥方式对铁的吸收、运输与分配的影响

 红色邻二氮杂菲铁示踪结果表明: 二价铁肥根系输液以二价态由根被动吸收, 由靠近形成层的木质部, 运输到根、茎、叶及其主脉内, 运输速度每小时可达数十厘米。室内营养液培养的八棱海棠苗用⁵⁹Fe示踪, 结果表明, 断根中分配的⁵⁹Fe为19.3% , 叶中70.9% , 断1、2、3条根⁵⁹Fe在叶中分配的比例分别为57.9%、63.6%和68.0%。铁肥树干强力高压注射以二价铁沿中央木质部的导管运输, 大部分向下运往根系, 根中贮存大量的铁, 向上运输稍难。运输速度每小时达数百厘米, 矫正缺铁失绿症的速度比根系输液慢, 但由于根中贮存大量的铁, 持效期较长。铁可以通过枝条和叶片进入树体并且运输。     

Physiological and biochemical responses for two cultivars of Pisum sativum (“Merveille de Kelvedon” and “Lincoln”) to iron deficiency conditions

The aim of this work was to compare the tolerance and the physiological responses to Fe deficiency of two Pisum sativum cultivars (“Merveille de kelvedon” and “Lincoln”) commonly cultivated in Tunisia. We studied the effects of Fe deficiency on: (i) chlorophyll content, relative growth rate (RGR) and Fe status, (ii) rhizosphere acidification, (iii) changes under Fe-deficient conditions in the activities of two root enzymes, the first related to the proton extrusion (H⁺-ATPase) and the second to iron reduction mechanism (Fe(III)-chelate-reductase: FCR). Three treatments were used: C, control, complete nutrient solution (CNS) containing 30 μM Fe; DD, direct deficiency, CNS without iron; ID, indirect deficiency, CNS containing 30 μM Fe + lime. Fe deficiency led to a significant decrease of chlorophyll content in both cultivars. The below reduction was observed in Fe-deficient plants of Merveille de Kelvedon. In addition, relative growth of shoots and whole plant was not affected by Fe deficiency. H⁺-ATPase and FCR activities were more stimulated in Merveille de Kelvedon than in Lincoln, under DD and ID Fe deficiency. The capacity of this cultivar to maintain plant growth and to preserve adequate chlorophyll synthesis under iron-limiting conditions is related to its better Fe-use efficiency, in addition to its high acidification and root reducing capacities. This allows us to suggest that Merveille de Kelvedon is more effective in overcoming Fe deficiency than Lincoln.     

Chlorocholine chloride application effects on photosynthetic capacity and photoassimilates partitioning in potato (Solanum tuberosum L.)

Treatment of potato (Solanum tuberosum L.) with chlorocholine chloride (CCC) applied twice as a foliar spray 25 and 30 days after planting has shown to decrease shoot and stolon growth but increase tuber yield. However, the regulatory role of CCC on translocation of recently fixed photoassimilates into different parts of potato plants has not been fully illustrated. In this study, ¹⁴C-isotope labelling technique was used to estimate the photosynthetic capacity and photoassimilate partitioning among leaves, stems, roots + stolons, and tubers of potted potatoes treated with 1.5 g l⁻¹ CCC. CCC treatment significantly increased tuber dry mass but reduced leaf dry mass. CCC-treated leaves had significantly higher chlorophyll and carotenoid contents and assimilated 22.0% more ¹⁴CO₂ per leaf dry mass than the controls. Compared with the control, CCC treatment reduced the translocation of ¹⁴C-photoassimilates into leaves, stems and roots + stolons but increased that into tubers. CCC-treated leaves exported 14.6% more ¹⁴C-photoassimilates into other parts of the plants. In addition, CCC treatment reduced ¹⁴C-soluble sugar and ¹⁴C-starch accumulation in leaves and stems but enhanced them in tubers and roots + stolons. Collectively, the results indicate that CCC treatment significantly improves the photosynthetic capacity of potato leaves and promotes photoassimilates partitioning into tubers thereby enhancing tuber growth.     

Gas exchange and antioxidant response of sweet pepper to foliar urea spray as affected by ambient temperature

This paper analyses the effect of different air temperatures (10, 20 and 30 °C) on the response of sweet pepper plants (Capsicum annuum L. cv. Herminio) to foliar urea applications after growing plants for 20 day with and without nitrogen (N) applied to the growing substrate. Leaf CO₂ assimilation, chlorophyll fluorescence, root respiration, lipid peroxidation and antioxidative enzymes were analysed. Spraying plants with urea increased leaf CO₂ assimilation of N-deficient plants when applied at 20 or 30 °C, compared with non-sprayed plants. When plants were sprayed with urea at 10 °C chlorophyll fluorescence of leaves was similar to that of plants that were supplied with full N in the nutrient solution. Root respiration was not affected by urea sprays whilst leaf NO₃⁻ concentration was increased by urea but only when it was sprayed at 10 or 20 °C. Lipid peroxidation and ascorbate peroxidase in N-deficient plants were reduced significantly by urea sprays, especially when plants were sprayed at 20 °C with N-limitation in the growing substrate. This study shows that N-limitation in the growing substrate induces a temperature-dependant increase in the activities of antioxidant enzymes in leaves of pepper and applications of foliar urea can be optimised, when applied at the appropriate temperature, to partly replace the N supplied to the roots of sweet pepper.     

Phosphorus toxicity in the Proteaceae: A problem in post-agricultural lands

South African Proteaceae are adapted to the low soil phosphorus (P) concentrations of the Cape Floristic Region. The efficient P uptake by Proteaceae means that these plants experience phosphorus (P) toxicity at lower rhizosphere [P] than crop plants. This is only problematic when cultivating Proteaceae (and many plants from this region) on previously agricultural land with high residual soil [P]. In this study we hypothesize that P toxicity will result in element imbalances in leaves of Proteaceae and information from this study aims to facilitate ameliorative treatments. Phosphorus toxicity was induced on-farm in Leucadendron ‘Safari Sunset’ (Proteaceae) with subsequent mapping of element distribution in non-necrotic leaf tissue using micro particle-induced X-ray emission spectrometry. Phosphate supply up to 0.01 mM in a fertigation solution resulted in increased stem length of Leucadendron ‘Safari Sunset’ while P concentrations in excess of this resulted in decreased stem length, increased leaf [P] up to 0.25% (w/w) and, between 1 mM and 5 mM P supply, typical P toxicity symptoms were observed. High P supply (5 mM P) resulted in increased leaf [P] in most leaf tissues including the epidermis, where calculations from an equilibrium speciation model indicated that there was 30% more dissolved PO₄³⁻ in the epidermis compared to leaves at low P supply (0 mM added P on soil with 34 mg P kg⁻¹). Concomitantly, bundle sheath and epidermal [Ca] were reduced and 10% more Ca was predicted to be adsorbed and precipitated as hydrapatite at high P supply. High P supply resulted in increased leaf [Cl] and [Mn] in all tissues studied; decreased total leaf [Fe], bundle sheath, xylem, phloem and epidermal [Fe] and decreased total leaf [Zn] and xylem and phloem [Zn]. The observed symptoms of P toxicity in Leucadendron ‘Safari Sunset’ (necrosis in some plants, chlorosis and leaf rosetting) co-occurred with (1) excess PO₄³⁻, which may bind Ca in the epidermis (leading eventually to necrosis); (2) reduced [Fe] and increased [Mn] (leading to chlorosis) and (3) reduced total and vascular [Zn] (leading to leaf rosetting).     

Effects of plant growth promoting rhizobacteria (PGPR) on yield,growth and nutrient contents in organically growing raspberry

During 2003 and 2005, plant growth promoting effects of two Bacillus strains OSU-142 (N₂-fixing) and M3 (N₂-fixing and phosphate solubilizing) were tested alone or in combinations on organically grown primocane fruiting raspberry (cv. Heritage) plants in terms of yield, growth, nutrient composition of leaves and variation of soil nutrient element composition in the province of Erzurum, Turkey. The results showed that Bacillus M3 treatment stimulated plant growth and resulted in significant yield increase. Inoculation of raspberry plant roots and rhizosphere with M3 and/or OSU-142 + M3, significantly increased yield (33.9% and 74.9%), cane length (13.6% and 15.0%), number of cluster per cane (25.4% and 28.7%) and number of berries per cane (25.1% and 36.0%) compared with the control, respectively. In addition, N, P and Ca contents of raspberry leaves with OSU-142 + M3 treatment, and Fe and Mn contents of the leaves of raspberry with M3 and OSU-142 + M3 applications significantly improved under organic growing conditions. Bacterial applications also significantly effected soil total N, available P, K, Ca, Mg, Fe, Mn, Zn contents and pH. Available P contents in soil was determined to be increased from 1.55 kg P₂O₅/da at the beginning of the study to 2.83 kg P₂O₅/da by OSU-142, to 5.36 kg P₂O₅/da by M3 and to 4.71 kg P₂O₅/da by OSU-142 + M3 treatments. The results of this study suggest that Bacillus M3 alone or in combination with Bacillus OSU-142 have the potential to increase the yield, growth and nutrition of raspberry plant under organic growing conditions.     

Essential and non-essential element composition of tomato plants fertilized with poultry manure

Poultry manure (PM) must be disposed of from poultry farms, but is a potentially valuable source of macro- and micronutrients for plant growth. The objective of this study was to examine the effects of poultry manure on the growth of tomato (Lycopersicon esculentum) plants. Yields of fruits and vegetative material of plants grown in soil with 0, 10, 20 and 40 g kg⁻¹ PM added were measured. Concentrations of N, P, K, Ca, Mg, S, Fe, Zn, Cu, Mn, Mo, Cl, Si, Br, Rb, Sr and Ba in leaves at flowering and at final harvest and in fruits were determined by polarized energy dispersive X-ray fluorescence (PEDXRF). Poultry manure fertilization improved tomato shoot growth and also fruit yield and increased leaf N concentrations at the harvest stage. In addition, P concentrations of the leaves and fruits were increased as the application rate of PM was increased. Fruit Ca and Mg were significantly reduced by increased rate of PM application, but not to the extent to cause the calcium deficiency disorder blossom end rot. Applied high levels of PM slightly increased the concentrations of leaf Mo and Br at the harvest stage. Poultry manure applications had a positive effect on the concentrations of leaf Zn, Cu, Cl and Rb at both sampling stages, but leaf Si concentration was reduced by PM treatments. The concentrations of Zn and Rb were increased in the fruits by PM treatments, but the concentrations of Br were decreased. Applied PM levels had no significant effects on the concentrations of K, S, Fe, Sr or Ba in tomato plants. It is concluded that the increased fruit yield, and the increased concentration of Zn (an element required in the human diet) and the lowered concentration of potentially harmful Br in the fruit make poultry manure a valuable growing medium for tomato production.