Accumulation and utilization efficiency of potassium in ramie varieties

Difference in nutrient utilization efficiency of genotypes of crops is attracting more and more attention of plant nutrition and breeding scientists. This experiment was carried out to reveal whether genotypic variation of potassium (K.) utilization efficiency exists in ramie [Boehmeria nivea (L.) Gaud.], by measuring K concentrations and accumulations in different organs in relation to the dry matter and fiber productivity of six field growing ramie varieties with evident dissimilarity in growth vigor. Potassium concentration decreased in leaves, petioles and seeding organ, but increased in stem wood and in the raw fiber of high raw fiber yield (RFY) varieties at the late growth stage. For different parts, stem bark attained the largest K concentration, followed in order by petiole, stem wood, seeding organs, raw fiber and leaves. Potassium concentration of stem wood, bark and raw fiber, respectively, demonstrated positive and significant correlation with RFY. Potassium utilization efficiency declined by harvest time. The results suggested that the ramie varieties with high biomass and RFY and K consumption such as Xiyeqing can be planted under the condition of abundant K resource, while Nindu‐Ramie variety may be used as high K efficient genetic resource for its ratios of RFY (g) and biomass (g) to K consumption (g) are over 25 and 114, respectively, in spite of its low biomass and RFY.     

Potassium‐transport rate from root to shoot unrelated to potassium‐use efficiency in tomato grown under low‐potassium stress

Four tomato (Lycopersicon esculentum Mill.) strains (203, 474, 546, and 576) that are equally efficient in potassium (K) absorption, but different in efficiency of K use were studied using a continuously flowing solution culture to determine the importance of K‐transport rate from root to shoot in relation to K‐use efficiency. Strains 203 and 546 are inefficient in K use, ratios of K in shoots to roots were found to be three times higher than those of the two K‐use efficient strains 474 and 576 when grown under low‐K stress (0.1 mM). In addition, both the K concentrations and rates of K flow in xylem exudates of decapitated strains 203 and 546 were significantly higher than those of strains 474 and 576. These results suggest that high rates of K transport from roots to shoots are unrelated to K‐use efficiency in the tomato strains grown under low‐K stress. Further studies of K distributions in leaves and stems found that K concentrations in matured leaves and stems of the two efficient strains 474 and 576 were markedly lower than those of the two inefficient strains 203 and 546, while K in young and expanding leaves of the efficient strains were significantly higher than those of the inefficient strains, indicating that the ability to mobilize K from matured leaves to young and expanding leaves is an important factor that contributes to K‐use efficiency in tomato plants grown under low‐K stress.     

Salinity tolerance and sodium localization in mycorrhizal strawberry plants

ABSTRACT

Salinity stress alleviation through arbuscular mycorrhizal fungi (AMF) application and sodium (Na) localization in strawberry plants were investigated. A greenhouse experiment in a completely randomized design with three replications revealed AMF (Gigaspora margarita) association alleviated salinity stress (200 mM NaCl). AMF inoculated plants had greater dry weight, maintained chlorophyll content, and decreased leaves browning compared to the control under salinity stress. The Na⁺ concentration and Na⁺/K⁺ ratio were found lower in the following organs, young and old leaflets and petioles, main roots and lateral roots of mycorrhizal plants than the control. The scanning electron microscope and energy dispersive x-ray spectroscopy (SEM-EDX) analysis of Na in old petiole and main root tissues revealed, excess Na localized in the vascular bundle margin of old petioles and main roots of both the control and mycorrhizal plants. So, suppression of Na absorption through roots might be the mechanism of salt stress alleviation in mycorrhizal plants than to the control Na localization. The higher cellulose and lignin contents in the cell wall of mycorrhizal roots act as the apoplastic barrier which might be suppressing Na influx.     

Genotypic Differences in Potassium Nutrition in Lowland Rice Hybrids

China imports most of its potassium (K) requirements for crop production. The objective of this study was to evaluate indica rice hybrids for K‐use efficiency. Twenty‐eight indica rice hybrids were evaluated in nutrient solution. The K influx rate was greatest in genotype Weiyou 64 (684.9 nmol K⁺ plant^?1 h^?1) and least in genotype Xie A/909 (457.2 nmol K⁺ plant^?1 h^?1). The K‐use efficiency was greatest in genotype ShanA/909 [81.8 mg dry matter (DM) produced per mg K taken up] and least in genotype Shanyou 64 (55.9 mg mg^?1). The maximum biomass was produced by genotype Shan A/4663‐5 (100.8 mg DM per plant), and the least biomass was produced by genotype Xie A/4663‐4 (59.1 mg DM per plant). These results suggest that K shortage for rice production can be alleviated by using K‐efficient rice genotypes.     

Salinity-Induced Changes in Ion Concentrations of ‘Hass’ Avocado Trees on Three Rootstocks

ABSTRACT

The effect of salinity (1.5, 3.0, 4.5, or 6.0 dS m^{? 1}) on ion concentrations [magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), and chloride (Cl)] of one-year-old ‘Hass’ avocado (Persea americana Mill.) trees on one of three rootstocks [‘Duke 7’ (D7), ‘Toro Canyon’ (TC), or ‘Thomas’ (TH)] was investigated. Concentrations of Mg decreased in roots, stems, and older leaves with increasing substrate salinity. Salinity had no effect on Ca concentration of the trees. Potassium concentrations decreased in roots of all trees and stems of trees on TH. Potassium concentrations either remained unchanged or increased at salinity levels of 3.0 dS m^{? 1} and above in leaves and buds of all trees. Sodium increased in roots and woody organs in trees on all rootstocks. Leaf Na concentrations increased with salinity in trees on D7 and TH, but not TC. Chloride increased in all organs of all trees with increasing salinity, but to the greatest extent in trees on TH and to the least extent in trees on TC. At high substrate salinity concentrations, leaves of trees on TH rootstock had the highest leaf concentrations of Na and Cl, and the highest Na:K ratios. Sodium and chloride concentrations were correlated with necrosis in older leaves of TH, but less so in leaves of trees on TC or D7. Based on percent necrosis in older leaves with increased salinity, trees on TH performed poorest, whereas trees on TC exhibited the greatest salt tolerance. Leaf necrosis was consistently observed at Cl concentrations of 4 mg g^{? 1} or more, and at Na:K ratios of 0.01 or more in older leaves. Chloride concentration and Na:K ratio in older leaves appears to be a useful marker for salinity tolerance screening in avocado rootstocks. The relative tolerance of the various rootstocks appeared to be due primarily to their ability to exclude Na and Cl from the leaves.     

Differential response of corn inbreds to calcium

Abstract

Differential responses were noted among several corn (Zea mays L.) inbreds for Ca when grown in nutrient solutions at varied Ca stresses. Properties of one of the more “Ca‐efficient”; inbreds (Oh43) compared to one of the more “Ca‐inefficient”; inbreds (A251) are reported.

Oh43 produced more dry matter and developed fewer Ca stress symptoms when grown at both low and high Ca or with high Mg and K than A251. Comparable dry matter was produced by Oh43 at 4 times less Ca than A251. Oh43 also produced more dry matter per unit Ca than A251. Oh43 leaves and roots had lower Ca concentrations than A251 leaves and roots. With added Ca to solutions, Mg, K, Mn, Zn, and Cu concentrations decreased more in A251 than in Oh43. A251 contained higher P concentrations than Oh43. Functional and critical Ca concentrations appeared to be lower in Oh43 than in A251. Oh43 should grow and adapt better to Ca stress conditions than A251.     

The effect of paclobutrazol on mineral nutrition of apple seedlings 1

Greenhouse grown ‘Golden Delicious’ apple seedlings were treated with soil drenches of paclobutrazol (PP333) at rates equivalent to 0.1, 0.2, 0.4, 0.8, and 1.6 kg of active ingredient (a.i.) ha.^‐1 Eleven weeks after treatment initiation, seedlings were harvested, divided into leaves, stems, and roots, weighed and analyzed for the content of macro‐and microelements. Shoot growth rate, leaf area, and total dry weight showed a decreasing trend with increasing rates of PP333. In contrast, specific leaf weight increased in response to growth regulator treatments. The total amount of N, Zn, and Cu absorbed by seedlings was not affected and that of K, Ca, Mg, and Mn was decreased by PP333 treatments. Concentration of Ca and Mn in leaves, N in roots, and N, Ca, Mg, Mn, Zn, and Cu in stems increased in response to PP333 treatments. The magnitude of these increases were dependent on the rate of growth regulator applied. Potassium was the only element which declined in concentration in leaves and stems; this was true, however, only at the two highest rates of PP333 (0.8 and 1.6 kg ha^‐1) Root K concentration was not affected by PP333 treatments.     

Calcium nutrition of white rose potato in relation to growth and leaf minerals

Abstract

White Rose potato plants were grown in nutrient solutions containing Ca from 0 to 20 meq/l. After 32 days of growth, 16 plant parts were taken for analysis. The critical level for the immature to the recently matured leaf was determined to be about 0.15% Ca for the petiole and the blade tissues at the breaking point of the transition zone. Ca concentrations of petioles and blades (dry basis) increased with leaf age with the greatest increase in the blade tissues. The petioles of recently matured leaves under severe Ca deficiency were higher in Na, Mg, and PO₄‐P, lower in N0₃‐N and about the same in K concentration in comparison with non‐deficient petioles while the corresponding blades did not differ appreciably. Calcium deficiency has no major effect on the uptake of these minerals since all values were in the adequate range.     

Use of Mefluidide to Alter Growth and Nutritive Value of Pearl Millet

Abstract

Pearl millet (Pennisetum americanum L. Leeke) has an inherent rapid growth rate that often presents management problems to achieve optimum utilization by livestock throughout the growing season. Both the rapid spring–summer growth rate and photoperiodism that diminishes growth in late summer—early fall creates the need to use both grazing and mechanical defoliation to have efficient use of forage production. The objectives of this 2‐year field study were to evaluate the effects of a growth regulator, mefluidide (N‐[2, 4‐dimethyl‐5‐([(trifluoromethyl) sulfonyl] amino) phenyl] acetamide), on growth characteristics and nutritive parameters of “Millex 24” pearl millet. Mefluidide was broadcast applied at different rates to determine the effect on dry matter (DM) yield and nutritive value of leaves and stems of pearl millet. Mefluidide reduced DM biomass at each weekly harvest, and at three weeks post‐treatment DM was reduced 3‐fold in Year 1 and 2‐fold in Year 2. Percent leaf, however, was nearly doubled by mefluidide application. Crude protein (CP) of leaves was not affected by mefluidide, however, CP of treated stems was significantly higher (P < 0.05) than untreated pearl millet. Fiber components were lowered (P < 0.05) in treated leaves and stems compared to untreated pearl millet. The 2‐year study showed that mefluidide enhanced nutritive value of pearl millet, but at the expense of DM.     

Potassium Fixation and Release Characteristics of Some Benchmark Soil Series under Rice–Wheat Cropping System in the Indo‐Gangetic Plains of Northwestern India

Abstract

Potassium (K) fixation and release in soil are important issues in long‐term sustainability of a cropping system. Fixation and release behavior of potassium were studied in the surface and subsurface horizons in five benchmark soil series, viz. Dhar, Gurdaspur, Naura, Ladowal, and Nabha, under rice–wheat cropping system in the Indo‐Gangetic plains of India. Potassium fixation was noted by adding six rates of K varying from 0 to 500 mg kg^?1 soil in plastic beakers while K release characteristics were studied by repeated extractions with 1 M HNO₃ and 1 M NH₄OAc extractants. The initial status of K was satisfactory to adequate. Potassium fixation of added K increased with the rate of added K irrespective of soil mineralogy and soil depth. Soils rich in K (Ladowal and Nabha) fixed lower amounts (18–42%) of added K as compared to Gurdaspur, Dhar, and Naura (44.6–86.4%) soils low in K. The unit fertilizer requirement for unit increase in available K was more in low‐K soils. The study highlights the need for more studies on K fixation in relation to the associated minerals in a particular soil. Potassium‐release parameters such as total extractable K, total step K, and CR‐K varied widely in different soil series, indicating wide variation in the K‐supplying capacity of these soils. K released with 1 M NH₄OAc extractant was 20–33% of that obtained with 1 M HNO₃. Total extractable K using 1 M HNO₃ varied from 213 to 528 mg kg^?1 and NH₄OAc‐extractable K ranged from 71 to 312 mg kg^?1 soil in surface and subsurface layers of different soil series. The Ladowal and Nabha series showed higher rates of K release than Gurdaspur, Dhar, and Naura series, indicating their greater K‐supplying capacity.     

Genotypic variation for potassium efficiency in wild and domesticated watermelons under ample and limited potassium supply

Potassium (K) is an important nutrient for watermelon (Citrullus lanatus Thunb. Matsum. & Nakai). However, there is little knowledge about genetic variations in K efficiency in watermelon. Sixty‐four watermelon genotypes were grown under conditions of ample (6 mM) and limited (0.1 mM) K supply in a glasshouse. Thirty‐eight wild genotypes (C. lanatus var. citroide) and 26 domesticated genotypes (C. lanatus var. lanatus) were cultivated hydroponically for 30 d. Shoot dry weight, shoot K concentration, K uptake, K‐use index (shoot dry weight / shoot K concentration), relative shoot dry weight (shoot dry weight under limited K / shoot dry weight under ample K), and relative shoot K concentration (shoot K concentration under limited K / shoot K concentration under ample K) were determined. Significant differences were observed among genotypes. The K efficiency was classified based on a medium‐efficiency interval which is equivalent to the 95% confidence interval of the mean relative shoot dry weight and relative shoot K concentration. Genotypic data above or below this interval were classified as either K‐efficient or K‐inefficient. We identified eight K‐efficient genotypes, of which four were wild types. Thus, wild watermelons can be used in breeding programs to improve the K efficiency of domesticated watermelons.     

Salinity and Irrigation Method Affect Mineral Ion Relations of Soybean

Abstract

Soybean [Glycine max(L.) Merrill] is moderately salt tolerant, but the method of irrigation used for crop production under saline conditions may influence the uptake and distribution of potentially toxic salts. This field study was conducted to determine the effects of application of saline waters by different methods, namely, drip and above‐canopy sprinkler irrigation, on the ion relations of soybean cultivar “Manokin”. Salinity was imposed by adding NaCl and CaCl₂ (1:1 by weight) to nonsaline irrigation waters. Saline treatments with electrical conductivity (EC _i ) of 4 dS m^?1 were compared with nonsaline controls (EC _i  = 0.5 dS m^?1). Ion concentrations in leaves, stems, roots, and when present, pods were determined at four stages of growth: vegetative, flowering, podding, and grain filling. Both Na⁺ and Cl^? were excluded from the Manokin leaves and stems when plants were drip‐irrigated and the uptake of these ions occurred solely via the root pathway. However, when saline water was applied by sprinkling, the ions entered leaves by both foliar absorption and root uptake and their concentrations in the leaves were about 9‐fold higher than in those under saline drip irrigation. Regardless of treatment, leaf‐K was highest during the vegetative stage, then decreased with plant age as K⁺ was mobilized to meet nutrient demands of the developing reproductive structures.     

Potassium Uptake and Utilization Efficiency Among Selected Nitrogen-Fixing Tree Legumes Over Time

Nutrients released from tree prunings sustain alley cropping. Potassium (K) uptake and utilization efficiency were monitored over 16 months in Gliricidia sepium, Leucaena leucocephala, and Albizia lebbeck. Tree interspecific variation arose in biomass yields and K nutrition. Tissue potassium concentration narrowed within 0.68–1.15% and varied little among tree parts and species over time. Potassium accumulation increased steadily with tree age and significant differences among trees occurred at all ages. Gliricidia sepium had a higher yield than the others over the first 8 months, after which the uptake pattern declined drastically to become the lowest at harvest. Differential K partitioning within trees occurred as K in leaves, stems, and roots amounted to 18, 35, and 47% in Albizia; 28, 25, and 47% in Gliricidia; and 27, 42, and 31% in Leucaena, respectively. Higher K allocation into Leucaena stems and its low partitioning into Albizia leaves were drawbacks for alley cropping. Potassium utilization efficiency decreased inversely to biomass yield and K uptake over time. It differed significantly among trees with Albizia being the most efficient. Low K returns from tree prunings in alley cropping could be due to its uptake potential and partitioning impairment in each species.     

Growth and Nutrient Absorption of Cape Gooseberry (Physalis Peruviana L.) in Soilless Culture

Cape gooseberry (Physalis peruviana L.) is a solanaceous plant. The growth and time-course of nutrient accumulation of the plant and its partitioning between roots, stems, leaves, and fruits were examined. The study was conducted analyzing two nutrient solutions in soilless culture under greenhouse conditions during two consecutive seasons. The macronutrient contents were analyzed. On average, the yield was 8.9 t·ha^?1. Growth of the plant until 90 d after transplanting obeys an exponential function of time and the relative growth rate for this period was determined. Nitrogen (N) was the element that showed the highest concentration, corresponding to leaves (4.67%), followed by potassium (K) in stems (4.46%). The highest accumulations of N, phosphorous (P), calcium (Ca), and magnesium (Mg) were found in leaves and of K in the stems. Potassium showed the highest nutrient accumulation (29 g·plant^?1) and the highest specific uptake rate.     

施氮对镉胁迫下杂交相思树生长及镉吸收分配的影响

【目的】研究不同水平氮的供应对木本固氮植物杂交相思树适应镉环境胁迫及其生物修复能力的影响,可为有目的地进行相思树栽培提供施肥依据。【方法】以杂交相思树 (Acacia mangium × Acacia auriculiformis) 为试材进行了盆栽试验。Cd2+ 设3个水平(0、30、60 mg/kg),在Cd2+ 30 mg/kg的基础上设施尿素2个水平(0.4、0.8 g/kg) ,共5个处理。研究了杂交相思幼苗的干物质、氮(N)、磷(P)、钾(K)、镉(Cd)的积累和分配规律。【结果】Cd2+ 胁迫显著抑制了杂交相思幼苗根、茎、叶和总干物质的积累,限制了N、P、K等元素的吸收和积累;杂交相思Cd转移系数为0.044～0.224,根Cd含量明显高于茎和叶,并且根部Cd累积能力要大于地上部;但Cd2+ 60 mg/kg胁迫下,杂交相思通过向地上部分转移Cd以更好地适应强胁迫环境。Cd2+ 30 mg/kg胁迫下,高氮 (0.8 g/kg) 较低氮 (0.4 g/kg) 更显著地促进了茎、叶和植株总的P、K积累,而低氮更有效地增加了根的N、P、K积累量;高氮较低氮更显著地提高了茎、叶干重以及干物质在茎叶中的分配比例,低氮则提高了根干重以及干物质在根中的分配比例和根冠比;Cd2+ 胁迫下施氮显著促进了杂交相思对Cd的吸收和积累,提高了Cd转移系数;低氮更显著地促进了根、叶和总Cd的积累,高氮更显著地促进了茎Cd的积累及Cd在茎、叶中的分配比例。【结论】Cd2+ 胁迫下杂交相思通过改变干物质及N、P、K、Cd积累和分配规律以及提高N、P和K利用率的方式,保证根系生长,以更好地适应胁迫环境。低Cd2+ 胁迫下 (30 mg/kg),施氮可缓解杂交相思由镉胁迫所引起的对N、K吸收的抑制,促进杂交相思各器官干物质以及N、P、K、Cd的积累。低施氮量 (尿素 0.4 g/kg) 促进相思树生长的效果更佳,高施氮量 (尿素 0.8 g/kg) 促进Cd向地上部的运转,提高其对Cd生物修复能力。     

Influence of phosphorus limitations on the growth,nutrient partitioning and physiology of mahogany (Swietenia macrophylla King) seedlings

The effects of four rates of phosphorus (P) fertilization (0, 0.56, 5.6 and 56.0 mg l^?1) in soilless medium on the growth and physiology of mahogany seedlings were examined. The greatest response occurred at the 56 mg l^?1 rate, with relatively small differences between other treatments. Biometric parameters increased at the 56 mg l^?1 compared to 0 mg l^?1 rate except root dry mass. Both the concentration and the total content of P and Kjeldahl nitrogen (N) increased in leaves, stems and roots with P application rate. Foliar concentrations of potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn) and sulfur (S) declined, and boron (B) and copper (Cu) increased with P limitations; zinc (Zn) and iron (Fe) were unaffected. Physiological adaptations of mahogany to P limitations include the preferential allocation of carbon (C) to plant roots, and increases in P utilization efficiency, P acquisition efficiency and the concentration of organic acids in xylem fluid. Root phosphatase activity was not influenced by P fertilization.     

Bicarbonate Had Greater Effects Than High pH on Inhibiting Root Growth of Zinc‐Inefficient Rice Genotype

Abstract

Effects of bicarbonate (10 mM as NaHCO₃) and high pH (pH 8 buffered with HEPES) separately on root growth and accumulation of organic acids in the roots of zinc (Zn)‐efficient (IR36) and Zn‐inefficient (IR26) rice genotypes (Oriza sativa L.) were investigated in this study. The results indicated that shoot dry matter yields were decreased more by bicarbonate than by high pH for the Zn‐inefficient genotype, but not affected for the Zn‐efficient genotype. Root dry weights, especially root length, was significantly decreased by bicarbonate and high pH treatments for the Zn‐inefficient genotype, whereas was considerably enhanced by only bicarbonate treatment for the Zn‐efficient rice genotype. The reduction in root growth of the Zn‐inefficient rice genotype and the enhancement of root length in the Zn‐efficient genotype were greater when plants grown with bicarbonate than with high pH treatment. Accumulation of malate, citrate, and fumarate in roots of the two genotypes increased considerably due to both high pH and bicarbonate treatments, but to a greater extent for the Zn‐inefficient than for the Zn‐efficient cultivars. After an 8‐day treatment, more organic acids accumulated in the roots of the Zn‐inefficient genotype (IR26) when plants grown with bicarbonate than at high pH, but this was not the case for the Zn‐efficient genotype. The influence of root growth by bicarbonate appeared to be one of the major factors for the sensitivity of rice genotypes to Zn deficiency in calcareous soils. The greater inhibitory effect of bicarbonate than high pH on root growth of the Zn‐inefficient genotype might result from an excessive accumulation and inefficient compartmentation of organic acids, particularly citrate and malate, in the root cells.     

Managing Citrus Trees to Optimize Dry Mass and Nutrient Partitioning

Abstract

Non‐bearing “Hamlin” orange trees on “Swingle citrumelo” rootstock (32 months‐old) grown on a Candler fine sand (hyperthermic, coated Typic Quartzipsamments) were harvested to estimate dry mass, nitrogen (N), phosphorus (P), and potassium (K) accumulation and partitioning into various parts of the tree. The above parameters were evaluated for trees grown under low or high fertilization rates, using either water soluble granular (WSG), controlled release formulation (CRF), or liquid fertilizer delivered through irrigation water, i.e., fertigation (FRT). Trees were irrigated using under tree sprinklers with a wetting area diameter of 3.0 m. Total dry mass per tree followed the order: CRF > FRT = WSG and FRT > CRF > WSG for the low and high fertilization rates, respectively. Effects of fertilizer source on dry mass of individual tree parts followed the above response pattern with few exceptions. Dry mass of tree parts in relation to total tree dry mass decreased in the order: trunk > branch > leaves > roots. Therefore, the woody portion of the tree represented the major proportion of tree dry mass. Total N content in trees varied from 28.4 to 50.4 g and 41.4 to 82.3 g with different fertilizer sources at the low and high fertilization rates, respectively. The tree total N content decreased in the order: CRF > FRT > WSG and FRT > CRF > WSG at the low and high fertilization rates, respectively. Nitrogen in the leaves represented the major proportion of tree N, regardless of N source or fertilization rate. Total K content of the tree was slightly lower than total N content. Effects of fertilization source on total K content was similar to that of total N content. Total P content in trees was considerably lower than that of either N or K content. Fertilization sources and rates had negligible effects on the P content.     

Glucosinolate profiles in the seeds,leaves and roots of rocket salad (Eruca sativa Mill.) and anti-oxidative activities of intact plant powder and purified 4-methoxyglucobrassicin

Abstract

Six desulfo-glucosinolates (DS-GSLs), DS-glucoraphanin, DS-4-(β-d-glucopyranosyldisulfanyl)butyl GSL, DS-glucoerucin, DS-glucobrassicin, DS-dimeric 4-mercaptobutyl GSL and DS-4-methoxyglucobrassicin, were isolated from rocket salad (Eruca sativa Mill.) By using high-pressure liquid chromatography (HPLC) and identified by their retention times on HPLC and electrospray ionization mass spectrometry (ESI-MS) techniques. Total GSL contents were 125, 11 and 22 µmol g^?1 dry weight (DW) in seeds, leaves and roots, respectively. Two DS-GSLs, namely DS-glucoraphanin and DS-glucoerucin, were the major GSLs in seeds and roots, while DS-glucoraphanin, DS-glucoerucin and DS-dimeric 4-mercaptobutyl GSL were the predominant GSLs in leaves (> 1 µmol g^?1 DW or > 10% of the total GSL content). In addition, the anti-oxidant activity (n = 3) of intact leaf and root powders, whole DS-GSL eluates and purified DS-4-methoxyglucobrassicin were measured using the XYZ-dish method. DS-4-methoxyglucobrassicin showed the greatest anti-oxidant activity value (3.8 unit g^?1 DW), and the value for whole DS-GSL eluates (1.6) was higher than that of intact leaves (1.5) and roots (0.87).     

IMPACT OF SALT STRESS ON MICRONUTRIENTS IN CORDYLINE FRUTICOSA VAR. ‘RED EDGE'

This trial was carried out to study the influence of the nutrient solution on the microelements concentration and distribution in C. fruticosa var. ‘Red Edge' plants. Four treatments were tested: T₁ [control, 1.5 dS m^?1, 14.3 mmol L^?1 sodium chloride (NaCl)], T₂ (2.5 dS m^?1, 22.2 mmol L^?1 NaCl), T₃ (3.5 dS m^?1, 32.7 mmol L^?1 NaCl) and T₄ (4.5 dS m^?1, 38.2 mmol L^?1 NaCl). In roots and stems, iron (Fe) concentrations were lower in the no saline treatment. Stems accumulated more Fe with treatments T₃ and T₄. Copper concentration and extraction were not affected by salinity. The highest manganese (Mn) concentration in roots was observed in T₂, while in petioles was higher in T₃ and T₄. Manganese extraction reached higher levels in the saline treatments in roots and stems, while in petioles it was lower in T₁, T₂ and T₃. In roots, zinc (Zn) concentration was lower with the extreme treatments. Micronutrients concentration in leaves was unaffected by salinity, because an exclusion mechanism that consists on accumulation in roots and stems was developed.