Leaf Zn Research Articles

Comparison study of zinc nanoparticles and zinc sulphate on wheat growth: From toxicity and zinc biofortification

ZnO nanoparticles (NPs) are studied as a potential solution to alleviate Zn deficiency in human diet due to their special physicochemical properties. However, information for food quality and safety in NP-treated crops is limited. The effects of ZnO NPs and ZnSO4 on germination and growth of wheat (Triticum aestivum L.) were studied in germination and pot experiments. Zn content increased significantly, ZnO NPs were more effective than ZnSO4 at increasing grain Zn content, but less effective at increasing leaf Zn, and no ZnO NPs were detected in the wheat tissues by NP-treatments, indicated by XRD. Both ZnO NPs and ZnSO4 at moderate doses increased grain yield and biomass. Compared with control, the maximum grain yield and biomass of wheat treated with ZnO NPs and ZnSO4 were increased by 56%, 63% and 55%, 72%, respectively. ZnSO4 was more toxic than ZnO NPs at high doses as measured by the inhibitory effects in seed germination, root length, shoot length and dry biomass of seedlings. Structural damage in roots and variation in enzyme activities were greater with ZnSO4 than with ZnO NPs. ZnO NPs did not cause toxicity different from that of ZnSO4, which indicates that ZnO NPs used under the current experimental conditions did not cause Nano specific risks.

Zinc status of apple orchards across apple growing regions of Balochistan

Abstract All plant essential nutrients except Molybdenum are not easily available in alkaline calcareous soils. Among them, the deficiency of micronutrients particularly Zinc and iron is widespread in crops and fruit orchards. For this purpose, a survey study was carried out across five districts of Balochistan viz Kalat, Killa Abdullah, Pishin, Quetta and Ziarat during 2016 aiming to determine both soil and leaf Zn status of apple orchards. The 150 soil and leaf samples were collected and statistically divided them as 30 samples of each district in 3 groups of 10 samples and analysed through one way analysis of variance. The results showed that soil pH of apple orchards was in alkaline range and EC was almost normal with statistically at par differences. While, the AB-DTPA extractable Zn in soil of various apple orchards across five districts revealed that 5, 23 and 2 orchards in Kalat, 3, 24 and 3 in Killa Abdullah, 15 15 and 0.0 in Pishin and Ziarat while 20, 10 and 0.0 in Quetta expressed low, marginal and adequate Zn concentration. The leaf tissue analysis for Zn status indicated that 23.3% apple orchards in Kalat, 6.7% in Killa Abdullah, 33.3% in Pishin, 73.3% in Quetta and 56.7% in district Ziarat were found Zn deficient. Consequently, this study suggest that Zinc supplementation to soil of these orchards are needed while the addition of compost under such alkaline soil also necessary and is considered as one of the best management practices for apple orchards. Keywords: Apple orchards; Leaf Zn concentration; Locations; Soil Zn concentration http://dx.doi.org/10.19045/bspab.2019.80034

Copper-based-zinc-boron foliar fertilizer improved yield, quality, physiological characteristics, and microelement concentration of celery (Apium graveolens L.)

ABSTRACTCelery is one of the most widely cultivated vegetables worldwide. Boron (B), zinc (Zn), and copper (Cu) are essential microelements for plant growth with Cu also important in controlling fungal diseases. But little is known about the combined effects of B, Zn, and Cu fertilizers on celery. A pot experiment was conducted during two growing seasons (2014–2015 and 2015–2016) using a novel foliar fertilizer: a copper-based-zinc-boron foliar fertilizer (Cu-ZnB) based on the Bordeaux mixture (BDM). Celeries were sprayed with water (the control); BDM; 1.0, 1.5 and 2.0 g L−1 copper foliar fertilizer (CFF1, CFF2, and CFF3), and with 1.0, 1.5 and 2.0 g L−1 the Cu-ZnB (Cu-ZnB1, Cu-ZnB2, and Cu-ZnB3). During both seasons, Cu-ZnB1 increased celery yield and decreased disease index, compared with control and BDM treatments. Application of Cu-ZnB1 also increased vitamin C content while reducing nitrate content of celery compared with BDM and increased leaf Zn and B concentration compared with the control, BDM, and CFF1 treatments. Furthermore, Leaf Cu concentration in Cu-ZnB1 treatment was lower by 76.9% compared with BDM. Spraying Cu-ZnB1 also significantly increased SOD, POD, and CAT activities, while decreasing MDA content of functional leaves. By applying Cu-ZnB during 2015–2\\016, soil available Cu concentration was reduced by 24.9–42.2%, compared with BDM. Hence, applying 1.0 g L−1 Cu-ZnB to celery is recommended for enhancing plant nutritional quality and yield; simultaneously, it reduces the levels of Cu in the soil and disease index of celery.

Ekmeklik ve Makarnalık Buğdaylara Uygulanan Çinko Dozlarının Kadmiyum Alımına Etkisi

Bu çalışmanın amacı, yüksek Cd konsantrasyonuna sahip toprağa çinko (Zn) uygulamaları ile ekmeklik ve makarnalık buğdayın Cd alımına olan etkisini araştırmaktır. Çalışma sera koşullarında Zn noksanlığına sahip kireç içeriği yüksek bir toprakta tesadüf blokları deneme desenine göre dört tekerrürlü olarak gerçekleştirilmiştir. Denemede Cd uygulamaları 0 (Cd 0) ve 10 (Cd10) mg kg-1 Cd dozlarında uygulanmıştır. Çinko uygulamaları ise topraktan 0 (Zn 0) ve 10 (Zn 10) mg kg-1 Zn ile toprak + yapraktan (Zn10+3Y; Zn10+8Y) olacak şekilde yapılmıştır. Yapraktan Zn uygulamalarına sapa kalkma döneminde başlanmış ve haftada 1 defa olmak üzere 3 ve 8 defa yapraktan %0,1 dozunda ZnSO4.7H2O uygulaması yapılmıştır. Bitkiler tane olgunluk döneminde hasat edilmiş ve tanelerde Zn ve Cd konsantrasyonları belirlenmiştir. Elde edilen sonuçlardan topraktan ve toprak+yapraktan Zn uygulamaları ile ekmeklik ve makarnalık buğdayların tane Zn konsantrasyonlarında önemli artışların olduğu görülmüştür. Toprağa Cd uygulaması ile Karacadağ çeşidine göre Harran-95 çeşidinin tanesinde daha fazla Cd birikimi olduğu görülmüştür. Karacadağ çeşidinin kontrol koşullarında 31 μg kg-1 olan Cd konsantrasyonu, Cd 10 koşullarında 3.616 μg kg-1‘e, Harran çeşidinin ise 70 μg kg-1 tane Cd konsantrasyonu Cd10 koşullarında 8.434 μg kg-1‘e yükseldiği görülmüştür. Bununla birlikte, toprak, toprak + yapraktan Zn uygulamaları, makarnalık buğday çeşitlerinin tane Cd konsantrasyonlarını önemli ölçüde azaltmıştır. Haran-95 çeşidinin Cd 10 koşullarında 8.434 μg kg-1 olan tane Cd konsantrasyonu, Zn10 koşullarında 6.464 μg kg-1‘a, Zn10+3Y koşullarında 7.932 μg kg-1‘a, Zn10+8Y koşullarında ise 6.745 μg kg-1‘a düşmüştür. Sonuçlardan makarnalık buğday çeşidinin ekmeklik buğday çeşidine göre topraktan daha fazla Cd aldığı görülmüştür. Bunun yanında topraktan ve yapraktan Zn uygulamaları ile makarnalık buğday çeşidinin Cd alımında daha fazla azalma olduğu görülmüştür.

Phenolic metabolism and related heavy metal tolerance mechanism in Kandelia Obovata under Cd and Zn stress

In the present study, a set of pot culture experiments was conducted to reveal how the metabolism process of phenolic compounds was affected by cadmium (Cd) and zinc (Zn) and to further uncover heavy metal tolerance mechanisms in Kandelia obovata. After 60d of treatment, the biomass and chlorophyll a content in the leaves were suppressed, but total phenolic compounds in roots and leaves were improved by the increasing gradient of Cd or Zn concentrations; Total phenolic compounds significantly increased by 3.6–44.6% in the roots, and by 0.4–126.6% in the leaves. At the meantime, the activity of Shikimate dehydrogenase (SKDH), cinnamyl alcohol dehydrogenase (CAD), and polyphenol oxidase (PPO) in the roots increased by 11.2–307.6%, 12.4–175.4% and − 2.7–392.8%, and the results were 3.4–69.5%, 1.7–40.0%, 16.0–99.7% in the leaves. Higher toxicity of Cd than Zn, as well as slight alleviating effect of 100 mg kg−1 Zn on 2.5 mg kg−1 Cd were found. Additionally, a significantly positive correlation coefficients for relationship between phenolic metabolism related enzyme activity and Cd/Zn contamination levels was found, and leaf SKDH, leaf CAD, and leaf PPO activities were moderately correlated with leaf Cd (r = 0.39, r = 0.43, and r = 0.57, respectively) and leaf Zn (r = 0.44, r = 0.41, r = 0.19, respectively) content, which indicate that Cd and Zn play a previously unrecognized but major role in phenolic compounds synthesis, transport, and metabolism in K. obovata. The results also provided evidence that the application of high levels of Cd and Zn was accompanied by three phenolic metabolism pathways participating in heavy metal tolerance process.

Growth and mineral content of coriander (Coriandrum sativum L.) plants under mild salinity with different salts

Soil salinity is a complex issue in which various anions and cations contribute to have a general adverse effect on plant growth. In the present study, effects of salinity from various salts including sodium chloride (NaCl), potassium chloride + sodium chloride + calcium chloride (KCl + NaCl + CaCl2), potassium sulfate + magnesium nitrate (K2SO4 + Mg(NO3)2) at two electric conductivities (EC) of 2 and 4 dS m−1 of irrigation water, and a distilled water control were evaluated on coriander plants (Coriandrum sativum L.). At EC = 2, all salts increased plant yield (shoot fresh weight) than control. Most growth traits including plant height, shoot fresh and dry weight, leaf SPAD value and vitamin C, leaf K, Mg and P concentrations were increased by K2SO4 + MgNO3, and remained unchanged by KCl + NaCl + CaCl2 treatment (except reduced plant height). Leaf’s zinc concentration reduced by either treatment. Even sodium chloride at EC = 2 showed some beneficial effects on leaf chlorophyll index, root fresh weight, leaf’s calcium and phosphorus concentration; however, most traits remained unchanged than control. Treatment of plants with NaCl or KCl + NaCl + CaCl2 at either EC increased the number of flowered shoots and leaf proline content than control. Most growth and quality traits including leaf minerals and vitamin C content were reduced by NaCl at EC = 4; however, shoot fresh and dry weights remained unchanged than control. Plant root fresh weight increased by NaCl at EC = 2 and decreased at EC = 4 than control. At EC = 4, shoot dry weight was increased and leaf Ca, P, Zn and Mn were decreased by KCl + NaCl + CaCl2, whereas shoot dry weight, leaf SPAD value and vitamin C content, leaf Mg and P were increased and leaf Zn was decreased by K2SO4 + MgNO3 than control. The results indicate that in contrast to sodium chloride, the salinity effects of other salts can not be detrimental on coriander plant growth.

Zinc pulverization alleviates the adverse effect of water deficit on plant growth, yield and nutrient acquisition in grapevines (Vitis vinifera L.)

Grapevine (Vitis vinifera L.) is an important dryland pulse crop in many parts of the world. However, productivity and quality are often limited by periods of water deficit. In a number of drought regions, drought is accompanied with zinc (Zn) deficiency, one of the most serious problems causing significant decreases in yield and quality in viticulture. In spite of this fact, possible effect of Zn treatment to alleviate the adverse effect of water stress on grapevines has not been studied. A pot culture research was designed under controlled glasshouse condition with the objective to investigate the effects of Zn pulverization on growth, physiology and nutrient acquisition of grapevine cultivars ‘Italia’ and ‘Alphonse Lavallée’ subjected to different irrigation levels. Six years old grapevines of the cultivars grafted on a drought tolerant rootstock Richter 99 (Berlandieri x Rupestris) were cultivated in pots (70 L) and subjected to two different irrigation regimes, FI-100% (replenishing the substrate water storage up to field capacity) and DI (40% of FI). Half of the vines for each irrigation group received leaf Zn pulverization (1%) twice (prior to flowering and berry set). DI caused overall decreases in shoot and leaf developments of cultivars, while Zn pulverization had alleviating effects on such vegetative growth in general. Generally, leaf chlorophyll content of the vines was also improved by Zn under both FI and DI conditions. Spraying of the leaves and green bunches with chelated Zn supported the grapevines of both cultivars ‘Italia’ and ‘Alphonse Lavallée’ in varying degrees by improving acquisition of many plant nutrients, promoting the vegetative and generative developments. Considering the overall response of the vines to Zn pulverization with a particular concern to DI condition, improved shoot and leaf growth, greener leaves, enhanced berry development and vine yield allow us to recommend Zn spraying as an environmentally friendly and sustainable cultural practice under drought stress which has been increasing with global climate change.

Foliar nutrient applications to ‘Wonderful’ pomegranate (Punica granatum L.). II. Effects on leaf nutrient status and fruit split, yield and size

Abstract Though pomegranates are beginning to be farmed more intensively, little is known about pomegranate leaf nutrient concentrations or the effects of foliar nutrient applications on those concentrations, including for one of the industry’s standard cultivars, Wonderful. Foliar nutrient applications could potentially be used in commercial pomegranate production, not only to improve plant nutrient status, but also to prevent physiological disorders, such as pomegranate fruit split, the most important physiological disorder in pomegranate production. Pomegranate trees at two ‘Wonderful’ commercial orchards were treated with foliar applications of zinc sulfate (ZnSO4; 0.3%, 0.4%, and 0.5%), magnesium sulfate (MgSO4; 1%, 2%, and 3%), potassium nitrate (KNO3; 1%, 2%, and 3%), or deionized (DI) water (control). Leaf mineral nutrient concentrations were determined and fruit were analyzed for fruit split incidence, yield, fruit number per tree, fruit diameter, fruit mass, aril mass, and mass of 100 arils. Leaf Zn concentrations were significantly higher in response to all foliar ZnSO4 treatments. Foliar applications of KNO3 resulted in significant increases in leaf N and K concentrations and foliar MgSO4 resulted in a significant increase in leaf S concentration. All foliar fertilizer types resulted in significantly lower fruit split incidence at one of the study sites. The foliar fertilizer treatments did not have a significant effect on fruit number per tree, fruit diameter and mass, mass of all arils in fruit, or mass of 100 arils. The results suggest that foliar ZnSO4, MgSO4, and KNO3 could be used to improve pomegranate nutrient availability and to decrease pomegranate fruit split incidence without negatively impacting fruit yield or size of ‘Wonderful’ pomegranate.

Phosphorus Fertilization Impacts on Corn Yield and Soil Fertility

ABSTRACTOptimization of phosphorus (P) fertilization is important for balancing soil fertility especially in vertisol to support economic crop production. The objective of the study was to determine the impact of P fertilization (1998 to 2014) on crop yield and nutrient uptake, and soil fertility under continuous annually tilled corn (Zea mays L.)-wheat (Triticum aestivum L.) system in semi-arid Mediterranean conditions. The study was conducted on Arik clay (isohyperthermic, fine clay Typic Haploxerert) using randomized complete block design with four replications for each treatment at the research farm of the Dept. of Soil Science and Plant Nutrition, Çukurova University, Adana, Turkey. P fertilizer at 0, 50, 100, 200 kg P2O5 ha−1 as triple superphosphate (TSP), respectively was applied a week before planting corn. Results showed that increasing P fertilization rates significantly decreased the number of mycorrhizal spores associated with corn roots. Similarly, a 10% decrease in corn root mycorrhizal colonization was observed with 200 kg P2O5 ha−1 fertilization. In the control treatment, corn yield was 4.3 Mg ha−1 as compared to 5.6, 5.7 and 6.1 Mg ha−1 in 50, 100 and 200 kg of P2O5/ha, respectively. The relationship between P fertilization and relative yield showed that more than 95% of the corn yield was produced when P applied at 100 kg P2O5 ha−1. While P fertilization significantly increased the leaf N, P, and K contents but decreased the leaf Zn, Fe and Mn contents, as compared with the control. However, P fertilization did not consistently affect the grain N and P contents. Both physiological efficiency- and agronomic efficiency of P fertilization have shown a significant non-linear increase than that of the control. Total organic C (TOC) and total N (TN) concentrations were more than 34 and 26% higher in 100 and 200 kg P2O5 ha−1rates as compared with the control. Likewise, available P (AP), manganese (Mn) and zinc (Zn) concentrations increased with an increase in P fertilization rates. The AP, Mn and Zn contents significantly stratified by P fertilization. Our results suggested that 100 kg P2O5 ha−1 is optimum to sustain Vertisol fertility for supporting economic corn production in the Mediterranean climates of Turkey.

Effects of aged ZnO NPs and soil type on Zn availability, accumulation and toxicity to pea and beet in a greenhouse experiment

Most studies have assessed the toxicity of pristine NPs to plants without considering the likely changes that these NPs will undergo during their residence time in the soil. In this study, we assessed the effects of ZnO NPs (3, 20, and 225 mg Zn kg−1 soil) aged for a year in soil and after a previous crop on the Zn availability in soil, leaf accumulation and toxicity to green pea (Pisum sativum L.) and beet root (Beta vulgaris L). The effects were compared to bulk ZnO and ZnSO4 in two agricultural soils with different pH under greenhouse conditions. The Zn concentration in the plant leaf was 6–12-fold higher in acidic than in calcareous soil that could explain the different effects on plants caused by Zn applications depending on soil type. Thus, in acidic soil, ZnO NPs promoted ROS generation in both plant species with increases from 47% to 130%, increased the MDA content in pea up to 58 ± 8% in plant exposed to ZnSO4 at 225 mg Zn kg−1 soil and altered the ratio of photosynthetic pigments in beet between 12% and 41%, suggesting distressed chloroplast constituents. In calcareous soil, the changes seemed to be related to the supply of Zn in Zn deficient soils, whose principal effect was the 20–65% decrease of ROS levels in treated plants. The available and leaf Zn concentrations did not differ among Zn sources. Likewise, ZnO NPs showed comparable toxic or stimulatory effects to ZnO bulk and Zn salt, with some exceptions where Zn ion showed the highest phytotoxicity and effectiveness as a micronutrient. According to our results, we cannot affirm that NPs pose a higher potential environmental risk than their bulk counterparts after one-year of residence time in soil.

Stress response of Triticum aestivum L. and Brassica juncea L. against heavy metals growing at distillery and tannery wastewater contaminated site

This study aimed to investigate the effects of potentially toxic elements on biochemical parameters in wheat (Triticum aestivum L.) and mustard (Brassica juncea L.) plants growing at distillery and tannery wastewater contaminated sites. The analysis of plants showed the highest accumulation of Fe (361 mg kg−1 in wheat root and 359 mg kg−1 in mustard leaves) followed by Zn, Cr and Mn in leaf>shoot>root. Further, the Chl-a, b, and carotenoids content was also found high in plant samples. Results also showed that photosynthetic content in wheat and mustard growing at tannery wastewater contaminated sites was Chl-a 3.92, 4.53 (mg g_1 fw), Chl-b 2.39, 1.29 (mg g_1 fw) and carotenoids 0.28, 0.32 (mg g_1 fw), respectively. Whereas, photosynthetic content in these plants with distillery waste was as Chl-a 3.43, 4.88 (mg g_1 fw), Chl-b 1.12, 2.05 (mg g_1 fw) and carotenoids 0.24, 0.29 (mg g_1 fw), respectively. In addition, the activity of plant enzymes such as SOD, APx, GPX, MDA, H2O2, and CAT was also higher in selected plants in comparison to control plants. Moreover, the high bioconcentration factor of Zn > 1 (1.29) and translocation factor >10 (10.31) of Cr in tannery wastewater affected mustard plants. This study concluded that industrial wastewaters are the primary sources of metal accumulation in agricultural crops and thus, it should not be discharged into the environment before its proper treatment. Hence, the continuous monitoring of sludge/soil, agricultural plants and water quality are imperative for the impediment of possible health hazards to animal and human beings.

Irrigation and Zn fertilizer management improves Zn phyto‐availability in various rice production systems

AbstractZinc (Zn) is an important micronutrient for rice (Oryza sativa L.) production and its deficiency has been observed in various production systems. High grain Zn concentration is equally important for high rice yield and human health. In this work, the effects of Zn fertilization on seedling growth, grain yield, grain Zn concentration, and their association with root traits were studied under alternate wetting and drying (AWD), aerobic rice (AR), system of rice intensification (SRI), and continuous flooding (CF). Zinc fertilization (15 kg ha−1) improved nursery seedlings chlorophyll and Zn concentrations, root length, and number of roots with highest values observed in CF. At harvesting, maximum plant height, panicle length, total and panicle bearing tillers, and kernel yield were found with Zn addition in AWD and CF rice systems. Mid season drainage provided at maximum tillering and Zn fertilization increased its concentration in leaves, culms, panicles, and grains under CF and AR at physiological maturity. Most of Zn applied was allocated into culms and panicles, nevertheless, a significant increase in grain Zn concentration was also observed in all production systems. Association of leaf Zn with grain Zn concentration was stronger than with culm and panicle Zn. The results indicate that Zn application after rice nursery transplanting is more important for grain Zn enrichment in all rice systems than for increase in grain yield in all systems except AWD where grain yield was also increased. More grain yield in CF and AWD as compared to SRI and AR can also be attributed to decreased spikelet sterility and to better Zn phyto‐availability in these rice systems at physiological maturity.

Synergic effect of arbuscular mycorrhizal fungi and bradyrhizobia on biomass response, element partitioning and metallothionein gene expression of soybean-host under excess soil zinc

The synergic effect of rhizobia (R) and arbuscular mycorrhizal (AM) fungi on the bioproduction, trace element partitioning and metallothionein gene expression of soybean-host was investigated under normal and elevated soil zinc conditions. In a completely randomized 3×4 factorial design, the experimental treatments – Zn addition (0, 200, and 400 mg Zn kg−1 soil) and inoculation (uninoculated control, R, AM, and RAM dual inoculation) were set up in the greenhouse for nine weeks. While the inoculants effectiveness was decreased in 400 mg Zn kg−1 soils, RAM induced significantly higher biomass production under all soil Zn treatments. The biomass response indicated that AM modulated stem and root bioproduction in favor of leaf/pod, while rhizobium favored root production and potentiated AM effect in dual inoculation. The partitioning of Zn and Mn in the hosts indicated synergic effects between AM and R, in RAM plants. Compared with control, AM lowered leaf Zn concentrations by reducing root Zn concentrations and modulating root-to-stem and stem-to-leaf Zn translocations. Compared to AM, RAM plants achieved lower leaf and pod Zn concentrations by mainly reducing root-to-stem Zn translocation. Zn treatment increased leaf and pod Mn in control plants, but symbionts countered this by regulating root-to-stem Mn translocation, especially in RAM. Type 1 metallothionein gene expression in roots was highest in RAM and lowest in control plants, but Zn effects were not dose-dependent. Synergisms in symbionts root colonization, number and greenness of leaves, element partitioning and metallothionein gene expression are indicated as important mechanisms underlying the effective partnership between AM and R, in the dual inoculation.

AtHMA4 Drives Natural Variation in Leaf Zn Concentration of Arabidopsis thaliana.

Zinc (Zn) is an essential element for plant growth and development, and Zn derived from crop plants in the diet is also important for human health. Here, we report that genetic variation in Heavy Metal-ATPase 4 (HMA4) controls natural variation in leaf Zn content. Investigation of the natural variation in leaf Zn content in a world-wide collection of 349 Arabidopsis thaliana wild collected accessions identified two accessions, Van-0 and Fab-2, which accumulate significantly lower Zn when compared with Col-0. Both quantitative trait loci (QTL) analysis and bulked segregant analysis (BSA) identified HMA4 as a strong candidate accounting for this variation in leaf Zn concentration. Genetic complementation experiments confirmed this hypothesis. Sequence analysis revealed that a 1-bp deletion in the third exon of HMA4 from Fab-2 is responsible for the lose of function of HMA4 driving the low Zn observed in Fab-2. Unlike in Fab-2 polymorphisms in the promoter region were found to be responsible for the weak function of HMA4 in Van-0. This is supported by both an expression analysis of HMA4 in Van-0 and through a series of T-DNA insertion mutants which generate truncated HMA4 promoters in the Col-0 background. In addition, we also observed that Fab-2, Van-0 and the hma4-2 null mutant in the Col-0 background show enhanced resistance to a combination of high Zn and high Cd in the growth medium, raising the possibility that variation at HMA4 may play a role in environmental adaptation.

Wheat flag leaf epicuticular wax morphology and composition in response to moderate drought stress are revealed by SEM, FTIR-ATR and synchrotron X-ray spectroscopy.

Wheat (Triticum aestivum L.) is the largest cereal crop grown in Western Canada where drought during late vegetative and seed filling stages affects plant development and yield. To identify new physiochemical markers associated with drought tolerance, epidermal characteristics of the flag leaf of two wheat cultivars with contrasting drought tolerance were investigated. The drought resistant 'Stettler' had a lower drought susceptibility index, greater harvest index and water-use efficiency than the susceptible 'Superb'. Furthermore, flag leaf width, relative water content and leaf roll were significantly greater in Stettler than in Superb at moderate drought stress (MdS). Visible differences in epicuticular wax density on the adaxial flag leaf surfaces and larger bulliform cells were identified in Stettler as opposed to Superb. Mid-infrared attenuated total internal reflectance spectra revealed that Stettler flag leaves had increased asymmetric and symmetric CH2 but reduced carbonyl esters on its adaxial leaf surface compared to Superb under MdS. X-ray fluorescence spectra revealed a significant increase in total flag leaf Zn concentrations in Stettler in response to MdS. Such information on the microstructural and chemical features of flag leaf may have potential as markers for drought tolerance and thereby accelerate the selection and release of more drought-resistant cultivars.

Horticultural performance and elemental nutrient concentrations on ‘Fuji’ grafted on apple rootstocks under New York State climatic conditions

Abstract A study was carried out to determine the horticultural performance and leaf and fruit elemental nutrient concentrations of 48 apple rootstocks grafted on ‘Fuji’ apple cultivar, and grown on a commercial farm in the Hudson Valley (Milton) New York State, USA from 2005 to 2015. Tree circumference was measured at the end of each year, and fruit yield data were collected from the third year (2007) to the eleventh year (2015). Leaf and fruit macro- and microelements were evaluated at the tenth year of the study. Most of the rootstocks evaluated survived well in the Hudson Valley conditions, with the exception of the Geneva ® (G or CG) rootstocks CG.4002 and CG.5030. The smallest trees were on CG.2034, M.27 and JM.4 and had the lowest cumulative yield and the lowest cumulative number of fruits, and medium to low fruit size, but the highest cumulative yield efficiency (kg cm −2 ). Other rootstocks, such as the dwarfing CG.2002, CG.2426, CG.4008, CG.5757, M.9 and the semi-dwarfing rootstock CG.6006, also had higher yield efficiencies. On the other hand, the medium vigor CG rootstocks such as CG.6001, CG.6253, CG.6976, and CG.8189 had high cumulative yield and high cumulative fruit number, and medium to high yield efficiency. Rootstocks had a significant influence on most of the fruit and leaf mineral concentration (dry weight basis). G.935, G.222 and CG.5257 conferred some of the highest values of fruit boron whereas M.9, M.27 and PiAu51.11 had the lowest. Fruit phosphorous values were closely associated with leaf boron, leaf potassium, and leaf sodium. Fruit calcium was highest in G.214, CG.2406, G.969, JM.4 and CG.5757, while the lowest values were with JM.1, PiAu51.11, and JTE-C. Fruit nitrogen values were lowest in M.7, PiAu51.4, B.54-118, and CG.8534 and the highest values were in the dwarfing rootstock CG.2034 and semi-dwarfing rootstock CG.4011. Weak but significant positive correlations were found between fruit size and leaf and fruit Mg, and leaf C. Significant correlations were found between nutrients: leaf B, P and K were highly positively correlated, and leaf Zn with leaf Mn and leaf Na. A strong positive correlation was found between fruit P and fruit K, fruit P and fruit B, and moderate positive correlation between fruit S and fruit K suggesting similar mechanisms of rootstock induction for these nutrients. These nutrient data are being utilized to customize scion nutrient requirements to rootstock-induced nutrient profiles.

Comparative effect of ZnO NPs, ZnO bulk and ZnSO4 in the antioxidant defences of two plant species growing in two agricultural soils under greenhouse conditions

The present study has investigated the toxicity of ZnO NPs to bean (Phaseolus vulgaris) and tomato (Solanum lycopersicon) crops grown to maturity under greenhouse conditions using an acidic (soil pH5.4) and a calcareous soil (soil pH8.3). The potentially available Zn in the soils and the Zn accumulation in the leaves from NPs applied to the soil (3, 20 and 225mgZnkg−1) and changes in the chlorophylls, carotenoids and oxidative stress biomarkers were measured at 15, 30, 60 and 90days and compared with those caused by bulk ZnO and ZnSO4. The available Zn in the soil and the leaf Zn content did not differ among the Zn chemical species, except in the acidic soil at the highest concentration of Zn applied as Zn ions, where the highest values of the two variables were found. The ZnO NPs showed comparable Zn toxicity or biostimulation to their bulk counterparts and Zn salts, irrespective of certain significant differences suggesting a higher activity of the Zn ion. The treatments altered the photosynthetic pigment concentration and induced oxidative stress in plants. ROS formation was observed at Zn plant concentrations ranging from 590 to 760mgkg−1, but the effects on the rest of the parameters were highly dependent on the plant species, exposure time and especially soil type. In general, the effects were higher in the acidic soil than in the calcareous soil for the bean and the opposite for the tomato. The similar uptakes and toxicities of the different Zn forms suggest that the Zn ions derived from the ZnO NPs exerted a preferential toxicity in plants. However, several results obtained in soils treated with NPs at 3mgZnkg−1 soil indicated that may exist other underlying mechanisms related to the intrinsic nanoparticle properties, especially at low NP concentrations.

Soil-applied ZnEDTA: Vegetative Growth, Nut Production, and Nutrient Acquisition of Immature Pecan Trees Grown in an Alkaline, Calcareous Soil

A field study was conducted to evaluate efficacy of soil-applied zinc (Zn) fertilizer on young pecan [Carya illinoinensis (Wangenh.) K. Koch] trees growing in alkaline, calcareous soils. Chelated Zn ethylenediaminetetraacetic acid (ZnEDTA) was applied at rates of 0, 2.2, or 4.4 kg·ha−1 of Zn via injection into irrigation water (fertigation) in microsprinkler irrigated ‘Western’ and ‘Wichita’ trees. Over the 5-year duration of the study, leaf Zn levels were increased from 22 to 35 µg·g−1 in the highest rate of ZnEDTA treatment compared with 7 to 14 µg·g−1 in unfertilized trees. Zn concentrations in shoot and root tissues were also elevated in Zn-treated trees. Zn treatments largely eliminated visible Zn deficiency symptoms, and increased trunk diameter growth compared with untreated trees. Nut yield (in the third through fifth seasons) were also increased as a result of Zn fertilization. No additional benefit in terms of trunk diameter growth or nut yield was observed by adding a higher rate of Zn (4.4 kg·ha−1) vs. the lower rate (2.2 kg·ha−1). ‘Western’ and ‘Wichita’ trees responded similarly to Zn fertigation.

Effect of leaf position on nutrients composition in Litchi (Litchi chinensis Sonn.)

The present study was conducted to explicate the influence of leaflets position on nutrients composition for two commercially growing litchi cultivars ‘calcuttia’ and ‘dehradun’ under sub mountane zone of sub tropics in north India. Samples of leaves were collected in March (September-October flush) from tagged branches after panicle emergence starting from 1st leaflet pair position to 6th leaflet pair from the terminal apex of the shoot. The collected leaf samples were analyzed for N, P, K, Mg, ca, Fe, Zn, cu and Mn concentrations on dry weight basis. Primary macro (N, P, K) leaf nutrients gradually decreased; whereas, secondary nutrients (ca, Mg) were increased in leaflet pair starting from top of the shoot to the lowest pairlet. Among the micro-nutrients, concentrations of Fe and Mn, increased from apex to basal leaflet pair while leaf Zn was decreased. Leaf Cu content showed inconsistent trends with respect to position of pair of leaflets. Wide fluctuations were observed among leaf micro-nutrients content and ‘dehradun’ litchi cultivar possessed higher mean concentrations of leaf nutrients than ‘calcuttia’ cultivar. In general, about 5–6 months old leaves, positioned at 2nd or 3rd pair of leaflet from the shoot apex should be collected in March to assess the leaf indexing in litchi cultivars under northern India conditions.

Assessment of Selected Heavy Metals in Onion Bulb and Onion Leaf (Allium cepa L.), in Selected Areas of Central Rift Valley of Oromia Region Ethiopia

This study was conducted to determine the levels of heavy metals (Pb, Cr, Cd, Fe, Cu, Zn, and Mn) in onion bulb and onion leaf around Mojo, Meki and Ziway areas to assess the concentrations of the heavy metals. The levels of the elements were determined using flame atomic absorption spectrometer. The concentrations of Cr in onion bulb and Fe in onion leaf were above the permissible level (2.3 mg/kg, 425.5 mg/kg) set by FAO/WHO at Mojo (4.87 mg/kg, 1090.40 mg/kg), Meki (4.13 mg/kg, 1836.47 mg/kg) and Ziway (3.33 mg/kg, 764.33 mg/kg) respectively. The results generally indicate that the consumption of these onion bulbs could be the health risk respective to Cr.