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1.
Radish (Raphanus sativus L.) exhibits a high efficiency in the utilization of sparingly‐soluble phosphates. A greenhouse experiment was designed to investigate the growth response of radish to different phosphorus (P) sources and the nutrient status of the rhizosphere associated with radish growth and nutrient absorption. Radish plants were grown in pots with the roots confined in rhizobags, in such a manner that the concentration of roots was very high within the rhizobag. The rhizosphere soils and non‐rhizosphere soils were analyzed separately for active silicon (Si), aluminum (Al), iron (Fe), and manganese (Mn) using Tamm's solution and for “available”; P using the Bray P1 extraction reagent. The radish growth response was mostly attributable to phosphate amount and availability, and the lime level used in the experiment. Concentrations of active Fe, Si, Al, and Mn were reduced in the rhizosphere, especially when lime and rock phosphate (Ps) were added. Available soil P was accumulated in the rhizosphere under lime and Ps addition, whereas its concentration was reduced with the zero lime treatment. Phosphorus utilization, characterized by P accumulation in shoots, was in accordance with the concentration pattern for “available”; P in the rhizosphere, but not with the growth response of radish itself. The calcium (Ca) concentration of the shoot followed the same trend as the radish growth. There was an antagonism between potassium (K) and Ca absorption as well as between Ca and magnesium (Mg) absorption. With the addition of P, shoot Mn concentration increased, while shoot Fe and Al concentrations increased with no lime addition but decreased with lime addition. The high P efficiency of radish is discussed from the view of rhizosphere chemistry. The high Mn efficiency of radish may be influenced by the same rhizosphere processes that are involved in its high P efficiency. It was concluded that rhizosphere processes and the status of nutrients determined the nutrient efficiency of radish and thus influenced its growth response and nutrient uptake.  相似文献   

2.
A greenhouse experiment was conducted to study the effects of cadmium (Cd) on growth, biomass yield, and Cd uptake in three radish (Raphanus sativus L.) varieties at the Indian Institute of Horticultural Research, Bangalore, India, during 2008–2009. Plants were subjected to different Cd levels by application of cadmium nitrate [Cd (NO3)2] at the rates of 0, 50, 100, and 200 mg Cd kg?1 soil. Length and fresh and dry biomass yields of shoots and roots decreased because of the phytotoxic effect of Cd. Among three varieties, Japanese White Long showed the greatest sensitivity to Cd toxicity. The accumulation of Cd in shoots and roots was greatest in Japanese White Long, which had greater bioconcentration factor values. Variety Arka Nishanth recorded lower bioconcentration factor values and greater transfer coefficient values, indicating lower Cd accumulation in root tubers in this variety. Hence, variety Arka Nishanth can be preferred in Cd-contaminated soils.  相似文献   

3.
Radish (Raphanus sativus cv. Akamaru‐Hatsukadaikon) was grown for several experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of radish shoots were observed. Two‐dimensional thin layer chromatography (TLC) and gas chromatography‐mass spectrometry (GC‐MS) analysis revealed the presence of endogenous indole‐3‐acetic acid (IAA) in Zn‐deficient radish shoots. An estimate has been made of alkali‐labile (1 and 7N NaOH) IAA in Zn‐deficient radish shoots with the use of gas chromatography (GC). The level of 7N NaOH‐labile IAA (peptidic + ester + free) and IN NaOH‐labile IAA (ester + free) in Zn‐deficient radish shoots was almost the same as that of control radish shoots. These results suggest that Zn nutrition did not affect the level of endogenous IAA in radish shoots.  相似文献   

4.
Ammonium nutrition of radish plants (Raphanus sativus L.) suppresses their accumulation of Ca. The objective of this study was to determine the critical Ca concentration of radish in order to assess if NH4 + nutrition induces Ca deficiency in this crop. Cultivar Cherry Belle was grown in sand culture in a greenhouse. Nitrogen was provided as nitrate or ammonium salts, and Ca was varied from 1 to 200 mg/liter in solution. With N03’ nutrition, plant growth increased curvilinearly with increased Ca in solution. Calcium accumulation in shoots was a good index of relative root (edible radish) growth. The critical Ca concentration in shoots for optimum root growth was 2% of the dry matter. With NH4+ nutrition, plant growth declined linearly with increased Ca in solution and with Ca accumulation in the shoots. A critical Ca concentration could not be determined for plants grown with NH4 + nutrition. The antagonism between Ca and NH4 + nutrition could not be explained by deficiencies or toxicities of other elements.  相似文献   

5.
Different origin composts and a digestate from a biogas plant and their respective alkali soluble (SBO) and insoluble (IOR) fractions have been tested as organic fertilizers in growth media. The materials have been characterized by determination of pH, salinity, C, N, P, and K content. A preliminary evaluation of the possible phytoxicity has been performed by determination of the germination indexes of cress (Lepidium sativum), white mustard (Sinapsis alba) and radish (Raphanus sativus). Most of the materials did not promote the germination of the seeds. Notwithstanding these negative results, the materials were also used as partial peat substitute in a commercial substrate to test the growth of marigold (Tagetes patula), radish (Raphanus sativus), and spinach (Spinacia oleracea). The dimension and dry weight of the plants grown on the substrate mixed with the composts, the digestate or the SBOs were similar to those observed on the substrate. Moreover, most of the SOBs provoked the increase of the dry weight of the roots of the radishes, therefore an increase of the quality. The insoluble fractions (IOR) from the composts allowed a growth of the plants similar to that obtained with a commercial substrate. In contrast, the IOR obtained from the digestate was phytotoxic.  相似文献   

6.
A radish and a grass species were grown in identical substrates either unpolluted or polluted by tungsten (W) at 1, 5, and 10 μg/g levels of watering solutions during 1 month under controlled laboratory conditions. Initially, at 4.1 μg/g, the W content in grass leaves reached 16 μg/g at the highest rate of W supply to the substrate. For radish, the content of W reached 22 and 29 μg/g in the leaves and roots, respectively. The overall W pollution increased significantly the mobility of major elements from substrate to grass leaves, especially at the 5 μg/g pollution level, whereas the W impact on radish leaves resulted in an increase of most contents, only Mn remaining unaffected. The roots from polluted radishes were enriched in Si by 21% and Al by 42% at low pollution, and in Si by 15% at high supply, whereas the uptake of the other elements remained unchanged. It looks like the W pollution at the levels chosen does not impact the transfer of the major and trace elements from roots to leaves of Raphanus sativus. Alternatively, metallic trace elements (Ba, Ni, Cr, Zn, W, Co) of the Raphanus sativus and Chloris gayana leaves outline similar content changes depending on the amount of W pollution. The total rare-earth element contents of the leaves of Raphanus sativus grown in the polluted substrates are lower than those of the leaves from unpolluted substrate. Their normalization in the leaves and roots of Raphanus sativus from the polluted substrates to those of the radish from non-polluted substrate provides flat patterns for both with a positive Eu anomaly for leaves, as for those of the grass and a negative Gd anomaly for roots. Also, addition of soluble W to the substrates induced an increase in the bacterial activity of the soil.  相似文献   

7.
The fate of allelochemicals in the soil environment largely determines the expression of allelopathy in the natural environment. In allelopathy research, the sorption of allelochemicals onto soil particles has been less well studied than their degradation. A study was carried out to evaluate the growth of cucumber (Cucumis sativus var Marketmore 76) and radish (Raphanus sativus var Crimson giant) in soil amended with 1, 5, 10 and 20 mg l–1 benzoic acid as model allelopathic substance. Growth of both cucumber and radish was not inhibited in soil amended with benzoic acid. A labeled study indicates that sorption of benzoic acid onto soil particles increases with concentration. Benzoic acid isotherms of both soils were non-linear, with an N value of 0.875 for a garden soil and 0.891 for a garden soil + sand, and they may explain the reason for the limited allelopathic effect of benzoic acid at concentrations often recorded in natural soil.  相似文献   

8.
Abstract

The elemental distribution between the leaves and roots of mature radish (Raphanus sativus cv Cherry Belle) plants grown in the greenhouse with various concentrations of nutrient solution B or Ca was determined to assess the role of phloem in the provision of nutrients to the root, and the retranslocation of B under deficient conditions. The relative composition and accumulation of elements in different parts, and the ratio of their concentrations in leaves:roots were used as a measure of their uptake, relative mobility and retranslocation. The data indicate that B, but not Ca is retranslocated in the phloem to the roots when that particular element was in short supply in the nutrient solution. B deficiency induced brown heart disorder in radish roots but the severity was dependent on the degree of deficiency below 28 μg g‐l DM in the root. These symptoms were alleviated when the root B concentrations were enhanced by foliar applications of B. It is concluded that radish responded to B deficiency in a fashion similar to that reported previously for rutabaga and that it might serve as a time‐saving model system for examining the mechanisms responsible for brown heart in rutabaga.  相似文献   

9.
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10.
Abstract

Captan [N‐(trichloromethylthio)‐4‐cyclo‐hexene‐l, 2‐dicarboximide] and benomy1[methyl 1‐(butylcarbamoyl)‐2‐benzimidazolecarbamate] were evaluated as nitrification inhibitors and compared with nitrapyrin [2‐chloro‐6‐(trichloromethyl)pyridine]. Nitrapyrin, captan, and benorayl were applied at 0, 20, 40, and 60 mg/kg with three nitrogen sources, KNO3, (NH4)2SO4, and urea, at 300 mg N/kg to ‘Cherry Belle’ radish (Raphanus sativusL). Nitrapyrin and captan inhibited nitrification effectively, but benomyl was not an effective inhibitor. Growth of radish roots and shoots was restricted with application of nitrapyrin and captan combined with (NH4)2SO4or urea relative to the comparable KNO3treatments. The concentrations of Ca, Mg, and NO3‐N in plants, especially in shoots, fell, and the percentage of ? was increased with the addition of nitrapyrin and captan. Benomyl did not affect plant growth or composition  相似文献   

11.
Summary Hydroxamate siderophores (HS) are microbially produced, ferric-specific chelates, known to occur in soil, and to be capable of providing iron to higher plants. This study examined the potential for HS to influence the diffusion of both iron and phosphorus to plant roots in soil.The HS desferrioxamine-B (DFOB) and desferriferrichrome (ferrichrome) were compared with the synthetic chelates ethylenediamine [di(o-hydroxyphenylacetic)acid] (EDDHA) and ethylenediamine-tetraacetic acid (EDTA), and citrate, oxalate, and distilled water in their ability to increase diffusion of iron using a simulated root technique. Chelate solutions were pumped through porous fiber bundles imbedded in soil previously labeled with55Fe. In a sandy loam of pH 7.5,55Fe diffusion caused by 10–4 M DFOB was twice that of water, but similar to that caused by 10–4 M EDDHA. However, 10–3 M EDDHA resulted in greater diffusion than 10-3 M DFOB. The diffusions resulting from equimolar quantities of citrate, oxalate, and EDTA were similar to that with distilled water. In a clay soil of pH 5.2 previously labeled with55Fe and32 P, the response in55Fe diffusion to chelate treatments was: 10–4 M EDDHA > 10–4 M ferrichrome > 10–3 M DFOB > 10–4 M DFOB > water. Both ferrichrome and EDDHA caused2 P diffusion to increase substantially over that of distilled water. These results suggest that hydroxamate siderophores present in the rhizosphere could effectively increase the level of soluble iron for root uptake and possibly increase phosphorus uptake by solubilization of phosphorus from iron phosphates at acid pH.  相似文献   

12.
The steel-making slag (SMS), a by-product of steel manufacturing process with an alkaline pH (11–12) and high amount of iron (Fe) and calcium (Ca) oxides, was used to reduce arsenic (As) phytoextractability. The by-product was selected as an alternative to commercial Fe oxides, which can decrease plant uptake, but they are expensive if used as amendments of contaminated arable soils. SMS was applied at rates 0, 2, 4, and 8 Mg ha−1 to an As (1 N HCl-extractable As 25 mg kg−1) contaminated soil prepared by mixing non-contaminated soil and mine tailings and cropped to radish (Raphanus sativa L.) seeding. Calcium hydroxide (Ca(OH)2), a common liming material in Korea, was applied at the same rates for comparison. Steel-making slag more effectively suppressed radish As uptake and increased yield than Ca(OH)2 due to stronger As immobilization because it significantly increased extractable Fe concentration and decreased extractable As. The SMS-treated soil showed an apparent increase in As chemisorbed by Fe and Al oxides and hydroxides of surface soil, As associated at the Fe and Al oxides and hydroxides of internal surfaces of soil aggregates, and Ca-associated As. The steel-making slag can be a good soil amendment to suppress As phytoextractability and improve nutrient balance in As-contaminated soil.  相似文献   

13.
Increasing the mobilization and root uptake of chromium (Cr) by synthetic and plant‐borne chelators might be relevant for the design of phytoremediation strategies on Cr‐contaminated sites. Short‐term uptake studies in maize roots supplied with 51CrCl3 or 51Cr(III)‐EDTA led to higher apoplastic Cr contents in plant roots supplied with 51CrCl3 and in Fe‐sufficient plants relative to Fe‐deficient plants, indicating that Fe stimulated co‐precipitation of Cr. Concentration‐dependent retention of Cr in a methanol:chloroform‐treated cell‐wall fraction was still saturable and in agreement with the predicted tendency of Cr(III) to precipitate as Cr(OH)3. To investigate a possible stimulation of Cr(III) uptake by phytosiderophores, Fe‐deficient maize roots were exposed for 6 d to Cr(III)‐EDTA or Cr(III)‐DMA (2'‐deoxymugineic acid). Relative to plants without Cr supply, the supply of both chelated Cr species in a subtoxic concentration of 1 µM resulted in alleviation of Fe deficiency–induced chlorosis and higher Cr accumulation. Long‐term Cr accumulation from Cr(III)‐DMA was similar to that from Cr(III)‐EDTA, and Cr uptake from both chelates was not altered in the maize mutant ys1, which is defective in metal‐phytosiderophore uptake. We therefore conclude that phytosiderophores increase Cr solubility similar to synthetic chelators like EDTA, but do not additionally contribute to Cr(III) uptake from Cr‐contaminated sites.  相似文献   

14.
Abstract

Mobilization of iron (Fe) chelated by humic acids (HA) of low (HA10,000) and high molecular weight (HA100,000) fractions and its uptake by plants were investigated in growth experiments with sunflower seedlings. The iron chelates (labeled with 59Fe) contained in dialysis bags (mw. cutoff=3500) were placed in minus iron Hoagland solutions as the Fe source and at the same time fulvic acid (FA), EDTA, and low and high molecular weight HA fractions were added in the solutions as mobilizators. Characterization of FA, HA10,000, and HA100,000 were performed by infrared spectroscopy and chemical analysis, e.g., total acidity, COOH, and phenolic‐OH content. Roots and leaves were harvested, dried, and ground for Fe activity determination. Iron contents and pH in the nutrient solutions were measured before and after treatments. The supply of Fe to the plants was apparently sufficient, because no Fe deficiency has been detected in the test plants but during the whole absorption period, the pH of the nutrient solution was about 4.5. The Fe contents in leaves indicated that part of the Fe was rapidly transported from roots to leaves. Judging from the Fe contents in leaves, it was assumed that the small size HA10,000 and EDTA were the most efficient in affecting transport of Fe from root to leaf tissue. FA, HA10,000, and especially HA100,000 were unable to penetrate the dialysis bags and, hence, were effective in Fe mobilization only after the Fe, dissociated from the Fe‐HA chelate, has passed the dialysis membrane into the nutrient solutions. In contrast, the small size EDTA was expected to have penetrated the dialysis bags, permitting mobilization of chelated Fe by ligand exchange inside the bags, and transporting the Fe to the roots. The results suggested that the humic substances used in this study were able to form with the Fe3+ ion complexes that maintained the iron available to the sunflower plants. In the chemical form of Fe.L, where L was FA o HA, the iron within the bags or in solution or in the roots free space, was available for exchange reactions with the natural sunflower plant chelators for its transport to the leaves.  相似文献   

15.
Abstract

The uptake and distribution of 32P from labelled monocalcium phosphate by white radish (Raphanus Sativus) roots at five phosphorus fertilization rates were studied.

After on initial period of degradation (approximately 6 weeks), there is a sharp decline of phosphorus uptake. Graphical representation in Tables and Figures of the phosphorus distribution is presented.  相似文献   

16.
A pot experiment was conducted to determine the effects of the application of composted tea leaves (TC), coffee waste (CC), and kitchen garbage (KC) on the nitrogen and nitrate accumulated in radish (Raphanus sativus L. cv. ‘radicula pers’), Chingensai (Brassica campestris L. cv. ‘Choyo No. 2’), and spinach (Spinacia oleracea L. cv. ‘Ban chu paruku’) as compared with the effect of inorganic 15N labeled fertilizer (IN) application. The compost was applied at the rate of 24 g kg?1 soil, corresponding to about 250 to 300 kg N ha?1; the A value method was used to estimate nitrogen uptake. Dry matter production was significantly higher in the IN and TC treatments than in the KC and CC treatments for all the species and tissue. Of the composts used, TC was most effective in increasing N uptake and N content in the vegetables. The composts derived N recovery as a percentage of total N uptake varied with plant species, 50.8%-62.9% in radish root, 35.3%-60.4% in radish leaf, 29.9%-48.2% in spinach leaf, and 31.3%-54.8% in Chingensai leaf. The N-use efficiencies of IN, TC, CC, and KC were 6.3%, 6.3%, 5.3%, and 6.6% in radish root; 13.6%, 9.7%, 8.4%, and 6.7% in radish leaf; 22.4%, 14.4%, 3.6%, and 5.8% in spinach leaf; and 61.2%, 39.5%, 25.5%, and 21.5% in Chingensai leaf, respectively. Nitrate accumulation in edible portions was highest in plants provided with IN as compared with those grown with composts, and nitrate content in radish root was markedly higher than that in the leaf. It is observed that the fate of compost derived N differed noticeably with vegetable species, plant part, and compost source.  相似文献   

17.
The effects of salicylic acid (SA) on iron (Fe) deficiency in peanut (Arachis hypogaea L.) were studied by adopting the hydroponic experiment. Iron deficiency caused serious chlorosis, inhibited plant growth and dramatically decreased the concentration of Fe in the roots. Furthermore, it decreased the active Fe content and chlorophyll content, and disturbed ionic homeostasis. In addition, Fe deficiency significantly increased the content of malondialdehyde (MDA) and the superoxide anion (O2??) generation rate. Addition of SA increased Fe concentration in the shoots and roots, active Fe content, chlorophyll content, the net photosynthetic rate, and transpiration rate. Moreover, SA supplementation alleviated the excess absorption of manganese (Mn), copper (Cu) and zinc (Zn) induced by Fe deficiency. In addition, the chlorosis symptom was alleviated and the plant growth was improved. Meanwhile, addition of SA increased the activities of catalase (CAT) and peroxidase (POD), and decreased the content of MDA and the O2?? generation rate. These results suggest that exogenous SA can alleviate Fe-deficiency induced chlorosis by promoting the plant growth, improving the efficiency of Fe uptake, translocation and utilization, protecting antioxidant enzymes system, and stimulating mineral element maintenance.  相似文献   

18.
To evaluate the effect of type of phosphate (P) material on reducing soil cadmium (Cd) extractability and radish Cd uptake in the field, two different P materials, fused superphosphate (FSP) and dipotassium phosphate (K2HPO4), were applied at rates of 0, 33.5, 100.5, and 167.5 kg P ha?1 before seeding radish (Raphanus sativa L.) in a Cd-contaminated soil. Plant-available Cd concentration in soil and total Cd uptake by radish increased with increasing FSP application but decreased with K2HPO4. The significant decrease in soil pH and negative charge of soil by FSP application led to an increase in bioavailable Cd fraction in soil and in Cd uptake by radish. However, K2HPO4 increased soil pH and negative charge of soil and decreased bioavailable Cd fractions. Soil pH and negative charge of soil played an important role in controlling Cd uptake by radish in soil to which phosphate was applied.  相似文献   

19.
The effects of humic acids extracted from two commercially‐available products (CP‐A prepared from peat and CP‐B prepared from leonardite) on the growth and mineral nutrition of tomato plants (Lycopersicon esculentum L.) in hydroponics culture were tested at concentrations of 20 and 50 mg L‐1. Both the humic acids tested stimulated plants growth. The CP‐A stimulated only root growth, especially at 20 mg L‐1 [23% and 22% increase over the control, on fresh weight basis (f.w.b.), and dry weight basis (d.w.b.), respectively]. In contrast, CP‐B showed a positive effect on both shoots and roots, especially at 50 mg L‐1 (shoots: 8% and 9% increase over the control; roots: 18% and 16% increase over the control, on f.w.b. and d.w.b., respectively). Total ion uptake by the plants was affected by the two products. In particular, CP‐A showed an increase in the uptake of nitrogen (N), phosphorus (P), iron (Fe), and copper (Cu), whereas, CP‐B showed positive effects for N, P, and Fe uptake. The change in the Fe content was the most appreciable effect on mineral nutrition (CP‐A: 41% and 33% increase over the control for 20 mg L‐1 and 50 mg L‐1 respectively; CP‐B: 31% and 46% increase over the control for 20 mg L‐1 and 50 mg L‐1, respectively). Increases in Fe concentration in the plant roots were especially pronounced (CP‐A: 113% and 123% increases with respect to controls for the 20 mg L‐1 and 50 mg L‐1 treatments; CP‐B: 135% and 161% increases with respect to the control for 20 mg L‐1 and 50 mg L‐1 treatments). On the basis of the current experiments and from evidence in the literature, reduction of Fe3+ to Fe2+ by humic acid is considered as a possibility to explain a higher Fe availability for the plants.  相似文献   

20.
Silicon (Si) can enhance the resistance of plants to many abiotic stresses. To explore whether Si ameliorates Fe2+ toxicity, a hydroponic experiment was performed to investigate whether and how Si detoxifies Fe2+ toxicity in rice (Oryza sativa L.) roots. Results indicated that rice cultivar Tianyou 998 (TY998) showed greater sensitivity to Fe2+ toxicity than rice cultivar Peizataifeng (PZTF). Treatment with 0.1 mmol L-1 Fe2+ inhibited TY998 root elongation and root biomass significantly. Reddish iron plaque was formed on root surface of both cultivars. TY998 had a higher amount of iron plaque than PZTF. Addition of Si to the solution of Fe treatment decreased the amount of iron plaque on root surface by 17.6% to 37.1% and iron uptake in rice roots by 37.0% to 40.3%, and subsequently restored root elongation triggered by Fe2+ toxicity by 13.5% in the TY998. Compared with Fe treatment, the addition of 1 mmol L-1 Si to the solution of Fe treatment increased xylem sap flow by 19.3% to 24.8% and root-shoot Fe transportation by 45.0% to 78.6%. Furthermore, Si addition to the solution of Fe treatment induced root cell wall to thicken. These results suggested that Si could detoxify Fe2+ toxicity and Si-mediated amelioration of Fe2+ toxicity in rice roots was associated with less iron plaque on root surface and more Fe transportation from roots to shoots.  相似文献   

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