Influence of potassium and magnesium fertilizer application on the yield and nutrient accumulation of maize genotypes under field conditions

The use of maize (Zea mays L.) genotypes that are able to utilize nutrients efficiently is an important strategy in the management of plant nutritional status; it is of particular importance with regard to potassium (K) and magnesium (Mg), due to their high requirement and influence on plant growth. The influence of K and Mg fertilizers on certain growth parameters of maize genotypes TM.815 and KL.72.AA, including length, seed in ear, seed weight growth, and nutrient concentration, was determined under field conditions over two successive years. The aim of the experiment was to study the effect of different rates of K and Mg fertilizers on maize genotype plant growth parameters, grain yield, and nutrient accumulation under field conditions.

A split plot design with three replicates was used and each block contained three treatments of 0, 100, and 200 kg ha^?1 of K₂O and 0, 10, and 20 kg ha^?1 of Mg; K₂SO₄ was used to supply K, and MgSO₄ was used for Mg.

Plants that responded to the K fertilizer had an increase in height, yield, and the concentration of K in the leaves and seeds. The addition of K fertilizer increased the concentration of nitrogen (N), iron (Fe), zinc (Zn), manganese (Mn), and K in the plant leaves and increased seed K concentration. Mg fertilizer increased the concentration of N, Fe, copper, and Mn in the leaves; however, it exerted no significant influence on K concentration. The KL.72.AA maize genotype had a higher mean plant height, number of seeds in ear, yield, and N, K, Fe, and Zn concentrations compared to the TM.815 maize genotype. In the experiment, the K fertilizer exerted a statistically significant effect on the leaf and seed K concentration; however, on a statistical basis, the Mg fertilizer did not affect the Mg concentration.     

Dry matter production,nutrient uptake,and growth of cotton as affected by potassium fertilization

Insufficient potassium (K) nutrition produces detrimental effects on cotton (Gossypium hirsutum L.) lint yield and fiber quality. To further understand the deleterious effects caused by K deficiency, a 2‐yr (1991 and 1992) field study was conducted to determine how dry matter partitioning and nutrient concentrations of various plant tissues for the cotton genotypes, ‘DES 119’ and ‘MD 51 ne’, were altered by varying the application rate of fertilizer K and nitrogen (N). All plots received a preplant application of 112 kg N ha^‐1, and half of the plots were later sidedressed with an additional 38 kg N ha^‐1. Within each N treatment, half the plots received 112 kg K ha^‐1, preplant incorporated, with the remaining plots not receiving any fertilizer K. Dry matter harvests were taken three times in 1991 and two times in 1992. At cutout (slowing of vegetative growth and flowering), plants that received K fertilization had a 14% more leaf area index (LAI), a 3% increase in the number of main stem nodes, and a 2% increase in plant height. However, those plants had a 12% lower specific leaf weight (SLW) than plants receiving no K fertilization. By the end of season, the of K fertilization had resulted in more stem (21%), bur (13%), seed (19%), and lint weight (20%), but harvest index was not affected. Varying the level of N fertilization did not affect any of these dry matter parameters at any harvest. In general, the larger plants produced under K fertilization had reduced concentrations of N, phosphorus (P), magnesium (Mg), and sodium (Na) in the various plant parts. While N uptake efficiency was not affected by K fertility, plants that received K fertilization had increased efficiency of fertilizer N use and of N utilization within the plant. The smaller LAI of the K deficient plants probably reduced the photosynthetic capacity per plant. A reduced assimilation capacity could explain the inefficiency of N use, lint yield reductions, and poorer fiber quality often associated with K deficiencies.     

肥料运筹方式对冬油菜生长及产量的影响

以湘杂油763为供试材料,研究了不同肥料运筹方式对冬油菜产量和部分农艺性状的影响。结果表明：氮肥运筹方式对油菜生长的影响较大,以基肥:苗肥:薹肥 = 5:2:3处理的籽粒产量最高,其次是基肥:苗肥:薹肥 = 6:2:2处理,基肥:苗肥:薹肥 = 10:0:0处理的产量最低,其差异达到了显著水平,单株角果数、每角果粒数、绿叶数、茎粗、最大叶长和叶宽、叶片叶绿素含量等指标也有类似的变化趋势,而氮肥运筹方式对千粒重的影响不显著。磷肥和钾肥运筹方式对油菜生长的影响较小,在不同磷钾肥运筹方式下籽粒产量、产量构成因素、茎叶性状均没有显著差异。在本试验所设的8种处理中,以氮肥的基肥:苗肥:薹肥 = 5:2:3、磷肥和钾肥的基肥:苗肥:薹肥 = 10:0:0 处理和氮肥的基肥:苗肥:薹肥 = 5:2:3、磷肥的基肥:苗肥:薹肥 = 6:2:2、钾肥的基肥:苗肥:薹肥 = 10:0:0 处理的籽粒产量并列最高。     

Fertility Response of Potato to Municipal Wastewater and Inorganic Fertilizers

This study evaluated fertilizer contribution of municipal wastewater on potato (Solanum tuberosum L.) cultivation in a split-plot experiment having two factors: water quality with 5 levels and fertilizer with 2 levels. Irrigation by raw wastewater supplied 16, 13, 13, 23, 1.7, and 83% of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), zinc (Zn), and boron (B) requirement of potato, respectively. Wastewater compared to freshwater, improved plant height, vigority, area coverage, leaf area index (LAI), stem per plant, number and weight of tuber per plant, above-ground dry matter (ADM), and tuber yield of potato. Averaged over 3 years, irrigation by 75 and 100% (raw) wastewater with recommended standard fertilizers produced the maximum, but identical, tuber yield. Wastewater raised N, P, and K contents in potato plants and tubers. Irrigation by wastewater could reduce the fertilizer requirement of potato by 10–15%. However, it caused high accumulation of total coliform (TC) and faecal coliform (FC) on potato skin, restricting the use of the produce.     

Effect of aluminium and calcium on growth of wheat seedlings and germination of seeds

Two separate experiments were conducted to investigate the aluminium (Al) and calcium (Ca) effects on wheat seedling growth and on seed germination. Wheat (Tritcum aestivum L, cs Yangmai No. 5) seedlings were grown for a 15‐day period and treated with 0.5 mM Al with low Ca (1 mM Ca) or high Ca (5 mM Ca). The growth of seedlings was signficantly inhibited by Al. Supplement of Ca improved the growth of Al‐treated plants, increased dry matter weight of plant and leaf area, and decreased shoot/root ratio. This showed that Ca ameliorated Al toxicity in wheat. In experiments on seed germination, Al concentrations less than 2 mM in the germinating medium had little or no visible effect on length of shoot and root of germinating seed. The germinating rate of seed was not affected significantly by Al, when Al concentrations lower than 5 mM Al. The addition of 3 mM Ca did not increase the length of shoot and root and germination rate of seeds. Both pretreatments with 6 mM Ca and 1 μM GA had no significant effect on the length of shoot and root and amylolytic activity of Al‐treated germinating seeds. No significant differences were found in the total amylolytic activity in Al‐treated and control seeds two days and five days after germination. The results of Al and Ca effects on seedlings and seed germination showed that Al‐toxicity on germinating seeds was different from on seedling growth. The high concentrations of Al inhibit growth of roots and shoots of germinating seeds by other toxicity mechanism rather than interaction of Al with Ca and mobilization of carbohydrate reserves.     

Influence of seed nitrogen content and biofertilizer priming on wheat germination in salinity stress conditions

In order to study the effects of seed nitrogen content and biofertilizer priming on germination indices of wheat seeds under salinity stress, a factorial experiment based on a completely randomized design with four replications was conducted in 2009. Experimental factors consisted of: (1) the application of different nitrogen fertilizer rates (0, 55, 110 and 165 kg ha^?1 N) on parent plants; (2) priming of achieved seeds by biofertilizers (Nitragin, Biophosphorus and distilled water); and (3) different levels of salinity produced by NaCl (0, ?0.4, ?0.8 and ?1.2 MPa). Germination percentage, germination rate, mean germination time, germination index, radicle and plumule length, radicle and plumule dry weight and radicle number per seedling were measured. Nitrogen application increased seed nitrogen content in parent plants. All germination indices decreased with increasing in salinity levels. Biofertilizer priming, especially Nitragin, had a positive effect on germination percentage, radicle number and radicle and plumule length in most salinity levels. The highest values for germination factors were related to achieved seeds from parent plants that were treated with 110 kg ha^?1 N. Overall, application of middle levels of N fertilizer (55 and 110 kg ha^?1 N) on parent plants combined with seed priming with Nitragin biofertilizer improved the germination indices of wheat under salinity stress.     

Effect of location on dwarf French bean (Phaseolus vulgaris L.) seed production and seedling vigour

ABSTRACT

This study examined if dwarf French bean (Phaseolus vulgaris L.) grown at northern latitudes develop seeds with superior yielding potential compared with plants grown at more southern latitudes. Two lines (BND3085 and BND3106) were grown at four sites across latitudes ranging from 52°N to 3°S. BND3085 and BND3106 seeds from Saskatoon grown plants (52°N) had the least damaged seed coats but the highest degree of electrolyte leakage from the seed and the lowest maximum germination rates. The Saskatoon (BND3085 and BND3106) and Nunhem (BND3106) seed lots had the lowest maximum germination rates when germinated at 28°C, 12°C, or when exposed to saline (100?mM NaCl) conditions. Saskatoon BND3085 seed produced plants with the lowest aboveground vegetative and total seed dry matter as well as the lowest pod number per plant. In contrast, plants grown from Saskatoon BND3106 seed produced 1.5-fold more total pods, 1.3-fold more total pods and 1.4-fold higher seed dry matter per plant as compared to plants grown from the Nunhem (51°N) or Arusha seed sources. This resulted in a 2.4–4.5% higher harvest index. These results suggest cultivar-specific dwarf French bean seed propagation at more northern sites may increase the productivity of the resulting crop.     

Comparative yield and chemical composition of soybean and fababean grown on chernozemic soils on the Canadian prairies

Abstract

Soybean (Glycine max (L.) Merrill) and fababean (Vicar faba (L.)) were grown under field conditions on six Orthic Black Chernozemic soils over three years at two levels of fertility. At flowering, full pod and maturity the yield and N, P, K and S composition of harvested plant materials were compared. Application of fertilizer (P, K and S) increased dry matter and seed yields of both crops. At all, growth stages fababeans produced more dry matter than soybean, and at maturity produced higher yields of seed, hull and stalk. However, the ratio of seed: hull: stalk for both crops was similar and constant at 3.8: 1: 4.7 on all soils and at both levels of soil fertility. At the high level of soil fertility, at the flowering and full pod stages, the concentration of N, P, and K in fababean was higher than that in soybean, but both crops had a similar concentration of S. At low fertility both crops had similar concentrations of P, K and S. At maturity, soybean seed had the higher concentrations of the four nutrients. The concentration of P in the hull and stalk of both crops was similar, but fababean hull had a higher concentration of K and soybean stalk a higher concentration of S. Soybean seed also had a higher protein content and yielded more protein per hectare than fababean seed.     

Flowering and podding characteristics on the main stem of soybean grown on varying levels of phosphate nutrition 1

Soybean (Glycine max (L.) Merrill) plants normally abort a high percentage of flowers and pods. This study was conducted to determine the effect of P nutrition on flower and pod abscission in soybean. Williams 82 soybeans were established in hydroponic culture in the greenhouse at four levels of P (0.45 mM, 0.20 mM, 0.10 mM or 0.05 mM), and main stem flowers and pods were counted every two days from flowering to maturity. The two highest P treatments had similar flower production, pod production, pod abortion, seed weight and seeds per pod, but the 0.20 mM P treatment had 20% lower dry matter production and 19% lower seed yield. At P supplies of 0.10 or 0.05 mM, flower production, pod production, flowers per node, pods per node, seed yield, seed number and weight per seed were less (P < 0.05) than at 0.20 mM. Flowers produced per main stem node and seeds per pod were largely unaffected by limited P. Plants supplied 0.10 or 0.05 mM P aborted more flowers and pods than did those supplied 0.45 or 0.20 mM P. At P supply of 0.05 mM, flower, pod and total abortion was 80%, 49% and 90%, respectively. Flower and pod production were 50% and 78% less, while plant dry weight, seed yield and weight per seed were 83%, 90% and 23% less, respectively for the 0.05 mM P treatment compared to control. The data indicate that the primary effect of limited P on reproductive growth of soybean is to increase flower and pod abortion.     

Effects of water‐soluble constituents of plant residues on water uptake by seeds

Abstract

There has been strong support for the hypothesis that the adverse effects of plant residues on crop yields are due to phytotoxic compounds derived from these residues. This hypothesis is based largely on studies showing that, when compared with distilled water, aqueous extracts of plant residues have an adverse effect on seed germination and seedling growth. Because seed germination and seedling growth are reduced by a delay in germination resulting from slow uptake of water by seeds, we studied the possibility that the adverse effects of aqueous extracts of plant residues on seed germination and seedling growth might be at least partly due to water uptake by seeds being retarded by water‐soluble constituents of these residues. To test this possibility, we compared the rates of water uptake and germination of seeds of corn (Zea mays L.), soybean [Glycine max. (L.) Merrill], and wheat (Triticum aestivum L.) when these seeds were treated with distilled water and with aqueous extracts of corn, sorghum [Sorghum bicolor (L.) Moench], and wheat residues. We found that the rates of water uptake and germination of seeds treated with aqueous extracts of plant residues were appreciably slower than the corresponding rates for seeds treated with distilled water. This may be due to the water potentials of these extracts (ca. ‐50 kPa) because when seeds of corn, sorghum, and wheat were treated with a solution of polyethylene glycol 8000 having a water potential similar to that of the extracts of plant residues tested, the rates of water uptake and germination were also slower than the corresponding rates for seeds treated with distilled water. These observations suggest that the adverse effects of aqueous extracts of plant residues on seed germination and seedling growth when compared with distilled water may be partly due to constituents of these extracts inducing water potential effects that reduce water uptake by germinating seeds.     

西藏高原环境下印度芥菜型油菜农艺性状的典型相关分析

为了调查西藏高原环境下, 印度芥菜型油菜的农艺性状表现, 本文以引进的20份印度芥菜型油菜为材料, 采用单因素随机区组设计并结合典型相关分析方法, 对其主茎性状(4个变量)、分枝性状(3个变量)、角果性状(3个变量)、生育期性状(4个变量)、产量性状(4个变量)等5组农艺性状(共含18个变量)间的典型相关关系进行了研究。结果表明: 印度芥菜型油菜单株产量主要由单株有效角果数决定; 影响印度芥菜型油菜产量性状最主要因素是角果性状, 其次是分枝性状、生育期性状和主茎性状; 印度芥菜型油菜在产量性状、角果性状、分枝性状、生育期性状、主茎性状等5组性状间均有密切的联系。本文所得结论可为引进印度芥菜型油菜新品种资源的开发和利用提供科学依据。     

红河干热河谷2年生吉贝人工幼林施肥效应研究

为明确吉贝幼林施肥配比及施肥量,采用单因素及N,P,K三因素L9(34)正交设计法,研究了施肥对2a生吉贝造林成活率及生长促进的影响。结果表明:(1)施基肥导致吉贝造林平均成活率下降6.92%以上,尿素200g/株处理与CK0差异显著;(2)施用复合肥400g/株、尿素300g/株处理树高、地茎增量与CK1差异显著,100g/株N+100g/株P+50g/株K、200g/株N+100g/株P+150g/株K组合树高、地茎、冠幅与CK1差异极显著,分枝数与CK1差异显著,除300g/株N+200g/株P+150g/株K组合增效指数小于尿素300g/株处理外,其余组合增效指数大于复合肥400g/株、尿素300g/株处理;(3)极差R比较认为,P肥对树高生长显著,N肥对地茎和冠幅生长较好,而分枝数第1年施K肥较P肥、N肥好,第2年施P肥较K肥、N肥好;(4)N,P,K组合较单因素肥效显著,肥效指数大小可作为吉贝幼林施肥生长快慢的衡量指标。可见,干热河谷吉贝造林以不施基肥为宜,尤其不能施尿素,幼林追肥经济效益显著,1～2a生林可采用100g/株N+100g/株P+100g/株K或200g/株N+100g/株P+150g/株K肥料组合以及复合肥400g/株、尿素300g/株单施。     

西藏高原环境下印度芥菜型油菜农艺性状的典型相关分析

为了调查西藏高原环境下,印度芥菜型油菜的农艺性状表现,本文以引进的20份印度芥菜型油菜为材料,采用单因素随机区组设计并结合典型相关分析方法,对其主茎性状(4个变量)、分枝性状(3个变量)、角果性状(3个变量)、生育期性状(4个变量)、产量性状(4个变量)等5组农艺性状(共含18个变量)间的典型相关关系进行了研究。结果表明:印度芥菜型油菜单株产量主要由单株有效角果数决定;影响印度芥菜型油菜产量性状最主要因素是角果性状,其次是分枝性状、生育期性状和主茎性状;印度芥菜型油菜在产量性状、角果性状、分枝性状、生育期性状、主茎性状等5组性状间均有密切的联系。本文所得结论可为引进印度芥菜型油菜新品种资源的开发和利用提供科学依据。     

Zinc delivery to plants through seed coating with nano-zinc oxide particles

In India, zinc (Zn) has been recognized as the fourth most important yield-limiting nutrient after nitrogen (N), phosphorus (P) and potassium (K). Supplementing the zinc (Zn) requirement of agricultural crops through water soluble zinc sulfate ZnSO₄ fertilizer is a costly management option whereas, utilization of ZnO (water insoluble and a cheaper material) as a source of Zn could be an alternative cost effective option to encourage farmers for wider adoption. In this present investigation, in order to supply the requisite amount of Zn to the plants, a protocol has been developed to coat the seeds of maize (Zea mays L.), soybean (Glycine max L.), pigeon pea (Cajanas cajan L.) and ladies finger (Abelmoschus esculentus L.) with microns scale (<3 µm) and nano-scale (<100 nm) ZnO powder at 25 mg Zn/g seed and at 50 mg Zn/g seed. Different Zn sources, ethyl alcohol, and crude pine oleoresin (POR) were used for coating of seeds. The germination test carried out with coated and uncoated seeds indicated better germination percentage (93–100%) due to ZnO coating as compared to uncoated seeds (80%). Pot culture experiment conducted with coated seeds also revealed that the crop growth with ZnO coated seeds were similar to that observed with soluble Zn treatment applied as zinc sulfate heptahydrate (ZnSO₄·7H₂O) (at 2.5 ppm Zn) which is evident from the periodic SPAD reading taken after 20, 25, 30 and 45 days after sowing. Application of Zn through different sources also enhanced the auxin indole-3-acetic acid (IAA) production in plant roots, which subsequently improved the overall growth. The most important advantage of seed coating with ZnO (both micron/nano-scale) is that it did not exert any osmotic potential at the time of germination of the seed, thus, the total requirement of Zn of the crop can be loaded with the seed effectively through nano-scale ZnO particle.     

Effect of seed phosphorus concentration on nodulation and growth of three common bean cultivars

Abstract

An experiment was conducted in the greenhouse to evaluate the effects of seed phosphorus (P) concentration on growth, nodulation, and nitrogen (N) and P accumulation of three common bean (Phaseolus vulgaris L.) cultivars. Seeds were produced under low or high soil P levels, and soaked, or not, in 200 mM KH₂PO₄ solution. The experiment had a 3×3×2×2 factorial block design: three cultivars (ICA Col 10103, Carioca and Honduras 35), three levels of applied P (15, 30 and 45 mg P kg^?1 soil), two native seed P concentrations, and two seed soaking treatments. Plants were harvested at flowering. Soaked seeds increased the number, dry mass and P content of nodules, but did not affect plant growth. Plants originated from seeds with high native P concentration presented higher shoot dry mass and nodule number and mass at every soil P level, and were less responsive to increased soil P supply, than plants from low seed P. In plants from seeds with high P, soil P levels did not alter significantly root dry mass, while in plants from seeds with low P bean cultivars expressed wider differences in root dry mass. The genotypic variability of nodulation was influenced by soil P levels and seed P concentration. Both higher soil or seed P supply enhanced N and P accumulation in shoots. These results indicate that a high seed P concentration produces plants less dependent on soil P supply, and can enhance nodulation and N₂ fixation of common bean. Seed P supply affected the cultivar performance, and should be considered in evaluation of bean genotypes.     

Growth,Yield and Quality Components of Canola Fertilized with Urea and Zeolite

In the present study, integration of nitrogen (N) and zeolite on growth, photosynthesis, yield and yield components, nitrate reductase activity, and plant nutrient content on canola (Brassica napus L. cv. SLM₀₄₆) was evaluated during two growing seasons (2010 and 2011) at East Azerbaijan Research Center for Agriculture and Natural Resources, Tabriz, Iran. The experiment was conducted as a 4?×?5 factorial design with three replications. Different levels of zeolite (0, 4, 8, and 12 ton ha^?1) and nitrogen (N; 0, 150, 200, 250, and 300 kg ha^?1) were added and mixed with soil thoroughly. According to combined analysis of variance, effect of year was significant only on silique number per plant, respiration rate, and iron (Fe) content. Also results indicated that N fertilizer increased plant height, silique number per plant, seed number per silique, 1000-seed weight, and finally seed yield. Similarly, zeolite increased yield and yield components whereas plant height was not affected by zeolite in the second year. Oil yield decreased due to N and zeolite application. In addition, photosynthesis and respiration improved on account of N and zeolite treatments. Nitrate reductase activity significantly was promoted by N and zeolite. Furthermore, micro- and macroelements were affected by N or zeolite application, so that N and zeolite decreased P content whereas N increased N, K, Fe, and zinc. In general our results demonstrated that zeolite application can increase canola growth and production, which may be through increasing N-use efficiency and improving soil physical characteristics.     

Alleviation of noxious effects of cattle ranch composts on wheat seed germination by inoculation with Azospirillum spp.

Two commonly-used composts from dairy cow manure that are used to improve poor structure and fertility of desert soils have inhibitory effects on wheat seed germination, probably as a result of their high levels of humic acids. Inoculation of wheat seeds with two species of the plant growth-promoting bacteria Azospirillum brasilense Cd and A. lipoferum JA4 (separately) prior to sowing in these amended soils improved germination, similar to the natural level of germination of seeds in desert soil without compost amendment. Both compost amendments increased height of wheat seedlings in the range of 20–25%, increased shoot dry weight by 15–19%, but severely decreased (51–54% less) root dry weight. Inoculation of wheat seeds with A. brasilense Cd, but not with A. lipoferum JA4, significantly increased plant growth parameters (height, shoot and root dry weight) over control plants grown in soil-compost mixtures. This bacterial species could survive for a period of 20 days in compost humic acid solution, could increase its population when the humic acids served as the sole carbon source, and may change the composition of humic acids in which it grows. We suggest that inoculation with A. brasilense may alleviate noxious effects on germinating seeds caused by compost application by possibly transforming the composition of humic acids in the compost.     

Effects of Solution Nitrogen and Plant Density on Annual Grass Seed Biochemistry and Progeny Phenotypic Plasticity

Abstract

Cogenerational phenotypic plasticity compensation to nutrient limitations and shoot densities (light limitation) among individual plants of the same species could provide an increased fitness. Planting density varying between 4 and 16 plants per container and solution nitrogen varying between 5 and 19 mM were used to test phenotypic plastic responses in oat (Avena sativa cv. Montezuma) seed biochemistry and the resulting progeny. Seed Kjeldahl nitrogen (N), magnesium (Mg), and both albumin–globulin (l M NaCl soluble) and prolamin–glutelin (residue) protein fractions were affected by a solution N × plant density interaction. Phosphorus (P) content was influenced by both treatment variables. The protein fractions, P, N, and Mg, in seeds from parent treatments were generally highest in the two higher planting densities. The contents of N, P, Mg, and the prolamin–glutelin fraction were highest at mid‐N (9 mM), except for the 16 plants per container where they were maximal at high‐N (19 mM). In contrast, the albumin–globulin fraction responded linearly to N availability. Seeds per plant decreased while seed weights increased, as plant density increased. The seed content of N, albumin–globulin, prolamin–glutelin, P, and Mg were all negatively associated with the number of seeds per plant. Germination rates of progeny were inversely related to parent plants N treatment. Progeny from the treatment plants (seeds × germination percent) were inversely related, over a five‐fold range, to parent density. Progeny shoot/root ratios (S/R) were directly influenced by the N treatment of parent plants, with progeny from the highest parent N treatment having the highest S/R. Seed N and P content and the prolamin–glutelin protein fraction concentration were correlated with progeny SR. Seed weight was negatively correlated with progeny S/R. Annual grass seed numbers and weights and the allocation of several seed constituents are environmentally influenced by plant density and solution N. These seed biochemical and physiological effects result in a reproductive fitness change and a cogenerational phenotypic plasticity influenced progeny fitness (S/R attribute).     

Physiological response of sunflower seedlings to salinity and potassium supply

Abstract

Sunflower seeds (Helianthus annutis L. cv. Dwarf) were grown only with increasing saline solutions [0, 50, and 100 mM sodium chloride (NaCl)] and potassium (K) supply to determine how salinity and K supply will affect plant germination and growth. Potassium supply under highly saline conditions (100 mM) or nonsaline conditions had a beneficial effect on sunflower seedlings germination which was not significantly altered with moderate salt concentrations (50 mM). During the stage studied, K supply in the absence of salinity increased significantly seedling biomass which reflects what is happening in the aerial part and root. This increase was proportionally higher in the stem than in the leaf with no variations in the foliar surface. In a saline environment, K supply did not markedly alter plant dry matter production, but increased foliar surface with moderate salt concentrations (50 mM) in the root environment.     

Zinc‐biofortified seeds improved seedling growth under zinc deficiency and drought stress in durum wheat

High zinc (Zn) concentration of seeds has beneficial effects both on seed vigor and human nutrition. This study investigated the effect of Zn biofortification on growth of young durum wheat (Triticum durum cv. Yelken) seedlings under varied Zn and water supply. The seeds differing in Zn concentrations were obtained by spraying ZnSO₄ to durum wheat plants at different rates under field conditions. Three groups of seeds were obtained with the following Zn concentrations: 9, 20, and 50 mg Zn kg^?1. The seeds differing in Zn were tested for germination rate, seedling height, shoot dry matter production, and shoot Zn concentration under limited and well irrigated conditions in a Zn‐deficient soil with and without Zn application. In an additional experiment carried out in solution culture, root and shoot growth and superoxide dismutase activity (SOD) of seedlings were studied under low and adequate Zn supply. Low seed Zn concentration resulted in significant decreases in seedling height both in Zn‐deficient and sufficient soil, but more clearly under water‐limited soil condition. Decrease in seed germination due to low seed Zn was also more evident under limited water supply. Increasing seed Zn concentration significantly restored impairments in seedling development. Drought‐induced decrease in seedling growth at a given seed Zn concentration was much higher when soil was Zn‐deficient. Increasing seed Zn concentration also significantly improved SOD activity in seedlings grown under low Zn supply, but not under adequate Zn supply. The results suggest that using Zn‐biofortified seeds assures better seed vigor and seedling growth, particularly when Zn and water are limited in the growth medium. The role of a higher antioxidative potential (i.e., higher SOD activity) is discussed as a possible major factor in better germination and development of seedlings resulting from Zn‐biofortified seeds.