Search

The present study investigated how foliar zinc (Zn) application affects seedling growth and Zn concentration of rice grown in a Zn-deficient calcareous soil with different soil Zn treatments. Seeds were sown in soil with five rates of Zn (0, 0.02, 0.1, 0.5 and 5.0 mg kg−1 soil) with and without foliar application of 0.5% ZnSO4. Seedlings were harvested at 35 days and separated into (i) the youngest leaves, (ii) the remaining shoot parts and (iii) roots. In soil with no Zn supply, shoot and root dry weight of the rice seedlings were significantly increased by foliar and soil Zn treatments. Plant growth was not clearly increased in low soil Zn treatments, while at each soil Zn treatment, foliar Zn application promoted growth of plants. Plants with adequate Zn supply had the highest Zn concentrations in the youngest leaf. Foliar Zn spray improved Zn concentration of the new growth formed after foliar spraying which shows that Zn is phloem mobile and moved from treated leaves into youngest new leaves. The results indicate clearly in rice seedlings that shoot growth shows more responsive to low Zn than the root growth. The results obtained in the present study are of great interest for proper rice growth in Zn-deficient calcareous soils but needs to be confirmed in other rice genotypes. [ABSTRACT FROM AUTHOR]

Maize (Zea maysL.) is the most widely grown crop in Bosnia and Herzegovina especially in Northwest part of the country. Considering that, the maize is extremely sensitive to micronutrient deficiency the main aim of this study was to asses: (1) micronutrient availability in soil, (2) micronutrient status in silage maize; and (3) the relationship between micronutrient soil availability and maize plant concentration. Soil samples for micronutrient availability (n = 112) were collected from 28 farms in 7 municipalities. Plant available micro- and macro- nutrients in soil were extracted using Mehlich-3, except plant available Se was extracted using 0.1M KH2PO4. Result showed that on average there was no significant difference between different soil types regarding their potential in plant available nutrients. P deficiency was present both, in soil and plants in whole region. Soil extractable P was ranging from 0.003–0.13 g kg−1and total plant P was ranging from 0.79–4.95 g kg−1. Zinc deficiency was observed in two locations both in soil (0.71 mg kg−1; 0.79 mg kg−1) and plant (11.5 mg kg−1; 15.8 mg kg−1). Potential Se soil deficiency was observed on some locations, while Se plant status is not high enough to meet daily requirements of farm animals. Extractable soil nutrients could be used as relatively good predictor of potential soil and plant deficiencies, but soil nutrient interactions and climate conditions are highly effecting the plant uptake potential. [ABSTRACT FROM AUTHOR]

In this work, Macro-Reversible addition fragmentation termination (RAFT) agents based on poly(ethylene glycol) (PEG) possessing different molecular weights and bearing benzoyl xanthate moieties were synthesized by the reaction of PEG potassium xanthate salts with benzoyl chloride, 4-methyl benzoyl chloride and 4-chloro benzoyl chloride. Controlled free radical polymerization of the styrene were carried out in the presence of these macro-RAFT agents using 2,2′-azobisizsobutyronitrile (AIBN) as an initiator to yield PS-b-PEG-b-PS block copolymers. The linear kinetic plot ln [M]o/[M] vs. polymerization time indicated that was first order with reference to monomer concentration. The block copolymerization possessed controlled/living character. The controlled character of the RAFT polymerization of the styrene was confirmed by the formation of narrow polydispersity of the polymers, linear increases in the molecular weight with polymerization time and molecular weight of the products that agreed well with theoretical values. Polymers having relatively narrow molecular weight distributions and predetermined number average molecular weights were obtained by the RAFT polymerization of the styrene. However, molecular weights of the polymers deviated from the theoretical values when low molecular weight RAFT agents are used. The results indicate that PEG benzoyl xanthate RAFT agents can more efficiently control the polymerization comparing methyl or chlorobenzoyl derivatives. The block copolymers were characterized by spectroscopic and GPC methods. [ABSTRACT FROM AUTHOR]

Zinc (Zn)–efficient wheat genotypes yield well on Zn-deficient soil. In this study, two Chinese wheat genotypes, Kenong9204 and Han6172, and two reference genotypes, Bezostaja (Zn efficient) and BDME10 (Zn inefficient), from Turkey were conducted to measure their physiological responses to Zn deficiency in the greenhouse. Results showed obvious genetic variation among the genotypes with Zn efficiency from 76% to 105%. Bezostaja and Kenong9204 had greater shoot dry weight and accumulated more shoot Zn content than BDME10 and Han6172 without Zn application. In one aspect of enzyme activities, Bezostaja and Kenong9204 presented significantly greater activities of superoxide dismutase while maintaining similar activities of catalase, ascorbate peroxidase, and glutathione reductase compared with inefficient genotypes BDME10 and Han6172 under Zn-deficient condition. Zinc-efficient genotypes are recommended to satisfy the sustainable grain yield in China and other areas, where Zn deficiency in soil is spread and multiple stresses may happen at times. [ABSTRACT FROM PUBLISHER]

This study evaluated how zinc (Zn) concentration of rice (Oryza sativaL.) seed may be increased and subsequent seedling growth improved by foliar Zn application. Eight foliar Zn treatments of 0.5% zinc sulfate (ZnSO4 · 7H2O) were applied to the rice plant at different growth stages. The resulting seeds were germinated to evaluate effects of seed Zn on seedling growth. Foliar Zn increased paddy Zn concentration only when applied after flowering, with larger increases when applications were repeated. The largest increases of up to ten-fold were in the husk, and smaller increases in brown rice Zn. In the first few days of germination, seedlings from seeds with 42 to 67 mg Zn kg−1had longer roots and coleoptiles than those from seeds with 18 mg Zn kg−1, but this effect disappeared later. The benefit of high seed Zn in seedling growth is also indicated by a positive correlation between Zn concentration in germinating seeds and the combined roots and shoot dry weight (r = 0.55,p < 0.05). Zinc in rice grains can be effectively raised by foliar Zn application after flowering, with a potential benefit of this to rice eaters indicated by up to 55% increases of brown rice Zn, and agronomically in more rapid early growth and establishment. [ABSTRACT FROM PUBLISHER]

The low availability of zinc (Zn) in soils and crops affects dietary Zn intake worldwide. This study sought to determine if the natural genetic variation in shoot Zn concentrations ([Zn]Shoot) is sufficient to pursue a crop improvement breeding strategy in a leafy vegetable crop. The gene-pool of Brassica oleracea L. was sampled using a large (n = 376) diversity foundation set (DFS), representing almost all species-wide common allelic variation, and 74 commercial varieties (mostly F1).The DFS genol:ypes were grown at low and high soil phosphorus (P) levels under glasshouse and field conditions, and also in a Zn-deficient soil, with or without Zn-fertilisation, in a glasshouse. Despite the large variation in [Zn]Shoot among genotypes, environment had a profound effect on [Zn]Shoot. The heritability of [Zn]Shoot was significant, but relatively low, among 90 doubled-haploid (DH) lines from a mapping population. While several quantitative trait loci (QTL) associated with [Zn]Shoot occurred on chromosomes C2, C3, CS, C7, and C9, these were generally weak and conditional upon growth conditions. Breeding for [Zn]Shoot in B. oleracea is therefore likely to be challenging. Shoot P concentrations increased substantially in all genotypes under low soil Zn conditions. Conversely, only some genotypes had increased [Zn]Shoot at low soil P levels. Sufficient natural genetic variation may therefore exist to study some of the interactions between Zn and P nutrition. [ABSTRACT FROM AUTHOR]

Multiphase block copolymers having the structure of poly(ε-caprolacton-b-etyhlene glycol-b-styrene-b-ethylene glycol-b-ε-caprolacton) were synthesized from poly(ethylene oxide) possesing azo group in the main chain by the combination of free radical polymerization (FRP) of styrene (S) and ring opening polymerization (ROP) of ε-caprolacton (ε-CL) in one-step. The block copolymers were characterized 1H-NMR and FT-IR spectroscopy and gel permeation chromatography (GPC). 1H-NMR and FT-IR spectroscopy and GPC studies of the obtained polymers indicate that multiphase block copolymers easily formed as a result of combination FRP and ROP in one-step. [ABSTRACT FROM AUTHOR]

Humic acids have many benefits for plant growth and development, and these effects may be maximized if these materials are combined with micronutrient applications. In the present study, pot experiments were conducted to evaluate the effects of zinc (Zn) humate and ZnSO4 on growth of wheat and soybean in a severely Zn‐deficient calcareous soil (DTPA‐Zn: 0.10 mg kg-1 soil). Plants were grown for 24 (wheat) and 28 days (soybean) with 0 or 5 mg kg-1 of Zn as either ZnSO4 or Zn humate. Zinc humate used in the experiments was obtained from Humintech GmbH, Germany, and contained 5% of Zn. When Zn was not supplied, plants rapidly developed visible symptoms of Zn deficiency (e.g., chlorosis and brown patches on young leaves in soybean and necrotic patches on middle‐aged leaves in wheat). Adding Zn humate eliminated Zn‐deficiency symptoms and enhanced dry matter production by 50% in soybean and 120% in wheat. Zinc‐humate and ZnSO4 were similarly effective in increasing dry matter production in wheat; but Zn humate increased soybean dry matter more than ZnSO4. When Zn was not supplied, Zn concentrations were 6 mg kg-1 for wheat and 8 mg kg-1 for soybean. Application of Zn humate and ZnSO4 increased shoot Zn concentration of plants to 36 and 34 mg kg-1 in wheat and to 13 and 18 mg kg-1 in soybean, respectively. The results indicate that soybean and wheat plants can efficiently utilize Zn chelated to humic acid in calcareous soils, and this utilization is comparable to the utilization of Zn from ZnSO4. Under Zn‐deficient soil conditions, plant growth and yield can be maximized by the combined positive effects of Zn and humic acids. [ABSTRACT FROM AUTHOR]

Phosphorus (P) efficiency (relative growth), which is described as the ratio of shoot dry matter or grain yield at deficient P supply to that obtained under adequate P supply, was compared in 25 winter wheat cultivars grown under greenhouse and field conditions with low and adequate P levels in a P-deficient calcareous soil. Adequate P supply resulted in significant increases in shoot dry weight and grain yield under both experimental conditions. In the greenhouse experiment, the increases in shoot dry weight under adequate P supply (80 mg kg−1) were from 0% (cv: C-1252) to 34% (cv: Dagdas). Under field conditions, the cultivars showed much greater variation in their response to adequate P supply (60 kg ha−1): the increases in shoot dry weight and grain yield with adequate P supply were between −2% (cv: Sivas-111/33) and 25% (cv: Kirac-66) for shoot dry matter production at the heading stage and between 0% (cv: Kirkpinar-79) and 76% (cv: Kate A-1) for grain yield at maturity. Almost all cultivars behaved totally different in their response to P deficiency under greenhouse and field conditions. Phosphorus efficiency ratios (relative growth) under greenhouse conditions did not correlate with the P efficiency ratios under field conditions. In general, durum wheat cultivars were found to be more P efficient compared with bread wheat cultivars. The results of this study indicated that there is wide variation in tolerance to P deficiency among wheat cultivars that can be exploited in breeding new wheat cultivars for high P deficiency tolerance. The results also demonstrated that P efficiency was expressed differently among the wheat cultivars when grown under greenhouse and field conditions and, therefore, special attention should be paid to growth conditions in screening wheat for P efficiency. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]