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1.
Summary Radiotracer studies revealed that the mechanism of zinc uptake was not purely non-metabolic. The over all uptake of Zn by intact plant ofPisum sativum L. (Var. T-163) occurred through an initial nonmetabolic phase followed by a metabolically mediated absorption. The translocation of zinc from plant roots to shoot was more sensitive to metabolic inhibitors and thus was a metabolic function.Research Publication No. 1541/116/0 through Experiment Station, G. B. Pant University, Pantnagar-263145, India. 相似文献
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3.
G. Janardana Rao G. Govindaraju Niranjali Sivasithamparam E. R. B. Shanmugasundaram 《Plant and Soil》1982,66(1):121-123
The mycotoxins citrinin, patulin and terreic acid are absorbed by rice seedling roots and translocated to shoots. Ten day analysis of toxin treated plants showed persistence of citrinin, patulin and terreic acid. All three toxins at a concentration of 100 ppm showed phytotoxic activity indicating terreic acid in addition to citrinin and patulin as phytotoxins. 相似文献
4.
Uptake of zinc by rye,bread wheat and durum wheat cultivars differing in zinc efficiency 总被引:5,自引:0,他引:5
Effect of zinc (Zn) nutritional status on uptake of inorganic 65Zn was studied in rye (Secale cereale, cv. Aslim), three bread wheat (Triticum aestivum, cvs. Dagdas, Bezostaja, BDME-10)
and durum wheat (Triticum durum, cv. Kunduru-1149) cultivars grown for 13 days in nutrient solution under controlled environmental
conditions. The cultivars were selected based on their response to Zn deficiency and to Zn fertilization in calcareous soils
under field conditions. When grown in Zn-deficient calcareous soil in the field, the rye cultivar had the highest, and the
durum wheat the lowest Zn efficiency. Among the bread wheats, BDME-10 showed higher susceptibility to Zn deficiency and Bezostaja
and Dagdas were less affected by Zn deficiency. Similarly to field conditions, in nutrient solution visual Zn deficiency symptoms
(i.e. necrotic lesions on leaf blade) appeared to be more severe in Kunduru-1149 and BDME-10 and less severe in rye cultivar
Aslim. Under Zn deficiency, shoot concentrations of Zn were similar between all cultivars. Cultivars with adequate Zn supply
did not differ in uptake and root-to-shoot translocation rate of 65Zn, but under Zn deficiency there were distinct differences; rye showed the highest rate of Zn uptake and the durum wheat
the lowest. In the case of bread wheat cultivars, 65Zn uptake rate was about the same and not related to their differential Zn efficiency. Under Zn deficiency, rye had the highest
rate of root-to-shoot translocation of 65Zn, while all bread and durum wheat cultivars were similar in their capacity to translocate 65Zn from roots to shoots. When Zn2+ activity in uptake solution ranged between 117 p M and 34550 pM, Zn-efficient and Zn-inefficient bread wheat genotypes were
again similar in uptake and root-to-shoot translocation rate of 65Zn.
The results indicate that high Zn efficiency of rye can be attributed to its greater Zn uptake capacity from soils. The inability
of the durum wheat cultivar Kunduru-1149 to have a high Zn uptake capacity seems to be an important reason for its Zn inefficiency.
Differential Zn efficiency between the bread wheat cultivars used in this study is not related to their capacity to take up
inorganic Zn.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
5.
Uptake and transport of foliar applied zinc (65Zn) in bread and durum wheat cultivars differing in zinc efficiency 总被引:5,自引:0,他引:5
Using two bread wheat (Triticum aestivum) and two durum wheat (Triticum durum) cultivars differing in zinc (Zn) efficiency, uptake and translocation of foliar-applied 65Zn were studied to characterize the role of Zn nutritional status of plants on the extent of phloem mobility of Zn and to determine the relationship between phloem mobility of Zn and Zn efficiency of the used wheat cultivars. Irrespective of leaf age and Zn nutritional status of plants, all cultivars showed similar Zn uptake rates with application of 65ZnSO4 to leaf strips in a short-term experiment. Also with supply of 65ZnSO4 by immersing the tip (3 cm) of the oldest leaf of intact plants, no differences in Zn uptake were observed among and within both wheat species. Further, Zn nutritional status did not affect total uptake of foliar applied Zn. However, Zn-deficient plants translocated more 65Zn from the treated leaf to the roots and remainder parts of shoots. In Zn-deficient plants about 40% of the total absorbed 65Zn was translocated from the treated leaf to the roots and remainder parts of shoots within 8 days while in Zn-sufficient plants the proportion of the translocated 65Zn of the total absorbed 65Zn was about 25%. Although differences in Zn efficiency existed between the cultivars did not affect the translocation and distribution of 65Zn between roots and shoots. Bread wheats compared to durum wheats, tended to accumulate more 65Zn in shoots and less 65Zn in roots, particularly under Zn-deficient conditions. The results indicate that differences in expression of Zn efficiency between and within durum and bread wheats are not related to translocation or distribution of foliar-applied 65Zn within plants. Differential compartementation of Zn at the cellular levels is discussed as a possible factor determining genotypic variation in Zn efficiency within wheat. 相似文献
6.
黄瓜初花期与结瓜期叶片可培养内生细菌多样性研究 总被引:1,自引:0,他引:1
【目的】研究黄瓜初花和结瓜两个生长期叶片可培养内生细菌的多样性。【方法】采用叶片表面消毒、菌种分离、16S rDNA序列扩增和系统发育分析进行了系统研究。【结果】两时期黄瓜内生细菌的种类、数量及优势菌的种类都有明显差异。初花期叶片含菌量为(2.6±0.18)106CFU/g鲜重,分离出的38株内生细菌分别属于短小杆菌属(Curtobacterium sp.)、节杆菌属(Arthrobacter sp.)、微杆菌属(Microbacterium sp.)等14个已知属,其中优势种类为短小杆菌属菌株;结瓜期叶片含菌量为(5.2±0.42)105CFU/g鲜重,分离出的43株内生菌分别属于泛菌属(Pantoea sp.)、假单胞菌属(Pseudomonas sp.)、芽孢杆菌属(Bacillus sp.)等11个已知属,其中优势种类为泛菌属菌株。【结论】初花期内生菌含量是结瓜期的5倍,两时期内生菌的种类表现出很强的差异,体现出黄瓜不同生育期可培养内生菌数量和种类的多样性,相关研究为黄瓜促生内生细菌的理论探索和生产应用提供一定的研究基础。 相似文献
7.
Experimental interruption of the root stele of Pisum sativum L. induces in the cortex tissue the development of wound-sieve tubes which bridge the wound and reconnect the vascular stumps. Outside the stele, sieve plates arise from primary pit fields. This origin is confirmed by the distribution of future sieve pores over the original parenchyma cell wall and by remnants of the pitfield cavity in developing sieve plates. Differentiation of wound-sieve elements is similar to that of bundle-sieve elements and includes the chromatolytic disintegration of nuclei as well as the development of typical sieve pores arising from pit-field plasmodesmata. The completion of first woundsieve tubes (indicated by a continuous chain of anilin-blue-positive sieve plates by-passing the wound) was observed 55–62 h after wounding. However, effective translocation, visualized with fluoresceine as a phloem-mobile marker, was not found until 10 h (on average) later. It is suggested that this time delay corresponds to the maturing of the last link within a chain of wound-sieve-tube members. Presumably, enucleate sieve elements with widened pores are a prerequisite for effective phloem translocation.Abbreviations DAPI
4,6-diamidino-2-phenylindole·2 H2O
- ER
endoplasmic reticulum
Preliminary results of this investigation have been presented at the International Phloem Transport Conference in Asilomar, Cal., USA 1985 (cf. Schulz 1986c) 相似文献
8.
Sun JY Jing MY Weng XY Fu LJ Xu ZR Zi NT Wang JF 《Biological trace element research》2005,107(2):153-165
Zinc (Zn) is an essential nutrient that is required in humans and animals for many physiological functions, including immune
and antioxidant function, growth, and reproduction. The present study was performed to investigate the effects of three Zn
levels, including Zn adequate (35.94 mg/kg, as a control), Zn deficiency (3.15 mg/kg), and Zn overload (347.50 mg/kg) in growing
male rats for 6 wk. This allowed for evaluation of the effects that these Zn levels might have on body weight, organ weight,
enzymes activities, and tissues concentrations of Zn and Cu. The results showed that Zn deficiency has negative effects on
growth, organ weight, and biological parameters such as alkaline phosphatase (ALP) and Cu−Zn superoxide dismutase (Cu−Zn SOD)
activities, whereas Zn overload played an effective role in promoting growth, improving the developments of organs and enhancing
immune system. Hepatic metallothionein (MT) concentration showed an identical increase tendency in rats fed both Zn-deficient
and Zn-overload diets. The actual mechanism of reduction of Cu concentration of jejunum in rats fed a Zn-overload diet might
involve the modulation or inhibition of a Cu transporter protein by Zn and not by the induction of MT. 相似文献
9.
《Fungal Biology Reviews》2018,32(4):236-248
Mushroom-forming fungi (restricted to basidiomycetous fungi in this review) differentiate by sensing several environmental factors for fruiting body formation. For fruiting body induction, nutrient, temperature and light conditions are critical environmental factors. Higher nitrogen and carbon sources in the media will suppress fruiting body induction in many mushroom-forming fungi, with induction being triggered by lower nitrogen and carbon concentrations. Low temperature or temperature downshift is another critical influencing factor for fruiting body induction in many cultivated mushrooms, such as Flammulina velutipes, Lentinula edodes, and Volvariella volvacea. Fungal response toward starvation and cold involves the production of sexual spores as the next generation. Species like F. velutipes and Coprinopsis cinerea can form fruiting bodies in the dark; however, light accelerates fruiting body induction in some mushroom-forming fungi. Remarkably, fruiting bodies formed in the dark have tiny or no pileus on heads (called dark stipe, pinhead fruiting body, or etiolated stipe). Light is essential for pileus differentiation in many, but not all mushroom species; one exception is Agaricus bisporus. Mushrooms have positive phototropism and negative gravitropism for effective dispersal of spores. Carbon dioxide concentrations also affect fruiting body development; pileus differentiation is suppressed at a high concentration of carbon dioxide. Thus, the pileus differentiation system of mushrooms may allow the most effective diffusion of spores. Full expansion of the pileus is followed by pileus autolysis or senescence. In C. cinerea, pileus autolysis occurs during spore diffusion. Fruiting body senescence, browning of gill, and softening occur after harvesting in several mushroom species. Fruiting body induction, development, and maturation in mushroom-forming fungi are discussed in this review. 相似文献
10.
Cd accumulation in durum wheat presents a potential health risk to consumers. In an effort to understand the physiological
mechanisms involved with Cd accumulation, this study examined the effects of Zn on Cd root uptake and phloem translocation
in a split– root system. Durum wheat seedlings were grown in chelate-buffered nutrient solution with intact root systems divided
into two sections. Each root section grew in a separate 1 l pot, one of which contained 0.2 μM CdSO4. In addition, each two-pot system contained ZnSO4 in the following combinations (in μm) (for -cd root system: +cd root system): 1:1, 1:10, 10:1,10:10, 1:19, and 19:1. Harvested
plant material was analyzed for Cd and Zn. In addition, rates of Cd and Zn net uptake, translocation to the shoot, and root
export (translocation from one root segment to the other) between days 8 and 22 were calculated. Results show that Zn was
not translocated from one root section to its connected root section. Uptake rates of Cd increased as solution Zn concentrations
increased. Cd translocation from one root section to the other decreased significantly when the Zn concentration in either
pot was greater than 1 μM. These results show the potential of Zn to inhibit movement of Cd via the phloem, and suggests that
providing adequate Zn levels may limit phloem loading of Cd into wheat grain. Increasing the rhizosphere activity of Zn2+ in Cd-containing soils may therefore result in reduced Cd accumulation in grain even while net Cd uptake is slightly enhanced.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
11.
C. A. Atkins 《Plant and Soil》1987,100(1-3):157-169
Summary Nitrogen (N2) fixed by Rhizobium bacteroids in the legume nodule is excreted as ammonia to the surrounding host cell where it is efficiently
assimilated into the amide group of glutamine. Generally glutamine is a minor exported solute of nitrogen, being further metabolised
to asparagine in temperate species and to the ureides, allantoin and allantoic acid in tropical species. These solutes serve
as the principal translocated forms of nitrogen in xylem. Compartmentalisation of the pathways of nitrogen metabolism and
the role of ammonia in regulation of their activity is examined in nodules of both asparagine-forming (Lupinus albus L.) and ureide-forming (Vigna unguiculata L. Walp) symbioses. 相似文献
12.
Summary The effect of Ca on the absorption and translocation of Mn, Zn and Cd in excised barley roots was studied using a multi-compartment
transport box technique. A radioisotope (54Mn,65Zn or115mCd)-labelled test solution was supplied to the apexes of excised roots and the distribution pattern in the roots was examined
in the absence or presence of Ca. Results obtained were as follows.
Addition of Ca to the test solution reduced the absorption of Mn and inhibited drastically its translocation in excised roots.
With increasing concentrations of Ca in test solutions, its inhibitory effects on the absorption and translocation of Mn became
severe.
Similar results were observed for the absorption and translocation of Zn. Ca in the test solution decreased the absorption
and inhibited drastically the translocation of Zn; as in the case of Mn, higher concentrations of Ca had severe effects on
these functions.
It was also evident that the addition of Ca to the test solution reduced the absorption of Cd at all levels of Cd concentration
(1, 10, and 100 μM). Cd absorption decreased with increasing concentrations of Ca in the test solution. However, Ca accelerated the translocation
of Cd in excised roots supplied with test solutions containing up to 10μM Cd. At 100μM Cd, addition of Ca caused a negligibly small acceleration of Cd translocation.
The accelerating effect of Ca on Cd translocation, especially “xylem exudation”, decreased markedly with the addition of 2,4-dinitrophenol,
but not with the addition of chloramphenicol or p-chloromercuribenzene sulphonic acid. When barley plants were supplied with
only CaSO4 during the entire growing period, that is, plants were not supplied with nutrient solution on the last day of this period,
Ca had no accelerating effect on Cd translocation in excised roots. 相似文献
13.
Uptake and transport of zinc in the hyperaccumulator Thlaspi caerulescens and the non-hyperaccumulator Thlaspi ochroleucum 总被引:12,自引:0,他引:12
Growth and zinc uptake of the hyperaccumulator species Thlaspi caerulescens J. & C. Presl and the non-hyperaccumulator species Thlaspi ochroleucum Boiss. & Heldr. were compared in solution culture experiments. T. caerulescens was able to tolerate 500 mmol m?3 (32.5 g m?3) Zn in solution without growth reduction, and up to 1000 mmol m?3 (65 g m?3) Zn without showing visible toxic symptoms but with a 25% decrease in dry matter (DM) yield. Up to 28 g kg?1 of Zn in shoot DM was obtained in healthy plants of T. caerulescens. In contrast, T. ochroleucum suffered severe phytotoxicity at 500 mmol m?3 Zn. Marked differences were shown in Zn uptake, distribution and redistribution between the two species. T. caerulescens had much higher concentrations of Zn in the shoots, whereas T. ochroleucum accumulated higher concentrations of Zn in the roots. When an external supply of 500 mmol m?3 Zn was withheld, 89% of the Zn accumulated previously in the roots of T. caerulescens was transported to the shoots over a 33 d period, whereas in T. ochroleucum only 32% was transported. T. caerulescens was shown to have a greater internal requirement for Zn than other plants. Increasing the supply of Zn from 1 to 10 mmol m?3 gave a 19% increase in the total DM of this species. liven the shoots from the 1 mmol m?3 Zn treatment which showed Zn deficiency contained 10 times greater Zn concentrations than the widely reported critical value for Zn deficiency to occur in many other plant species. The results obtained suggest that strongly expressed constitutive sequestration mechanisms exist in the hyperaccumulator T. caerulescens, which detoxify the large amount of Zn present in shoot tissues and decrease its physiological availability in the cytosol. Both T. caerulescens and T. ochroleucum had constitutively high concentrations of malate in shoots, which were little affected by different Zn treatments. Although malate may play a role in Zn chelation because of the high concentrations present, it cannot explain the species specificity of Zn tolerance and hyperaccumulation. 相似文献
14.
Uptake and translocation of calcium in cucumber 总被引:1,自引:0,他引:1
Bengt Bengtsson 《Physiologia plantarum》1982,54(2):107-111
Uptake and translocation of Ca2+ (45 Ca) were compared with water translocation in 12-day old intact plants and excised roots of cucumber ( Cucumis sativus L. var. Cilla), which had been cultivated in nutrient solution. No immediate reduction of Ca2+ uptake was found when water translocation was reduced by excision of the shoot. In the presence of 2,4-dinitrophenol Ca2+ translocation was reduced in the intact plants while water translocation was unchanged. It is suggested that regulation of Ca2+ uptake is primarily achieved in the root. The DNP-sensitive mechanism of Ca2+ uptake was associated with the root and probably represented transport through the endodermis into the stele. 相似文献
15.
Many microorganisms are capable of sequestering and concentrating heavy metals from their aqueous environment. While much research has beep carried out on the uptake of single species of metal ions, little attention seems to have been given to the study of multimetal ion systems. A mathematical model has previously been developed to describe the uptake of individual metal species by a microorganism. The model proposes two sequential processes: an initial rapid uptake due to cellular surface adsorption and a subsequent slow uptake due to membrane transport of the metal into the cells. This article extends the treatment by considering the uptake of two metal species together, cadmium and zinc, under different experimental conditions. The results are discussed in terms of possible mechanistic interactions. 相似文献
16.
Structure-induced non-uniform water flow induces a heterogeneous distribution of surface-applied radionuclides in the soil
profile. This study was conducted to assess the amount of 134Cs which can be taken up by a single root growing in an area enriched in 134Cs relative to the total amount of 134Cs that can be taken up by the whole root system growing in an area homogeneously contaminated with 134Cs. A split-root experiment was used to simulate the heterogeneous distribution of 134Cs and roots. Seedlings of maize (Zea mays L. cv Corso) were grown for 14 days in solution culture and then transferred to a two-compartment pot system, where a single
root was grown in a 134Cs contaminated compartment while the rest of the root system was grown in an uncontaminated compartment. Plants with the
whole root system growing in a solution contaminated with 134Cs were used as control. We tested the effect of the competition between Cs and K on the uptake and translocation of 134Cs by using two K concentrations, 0.2 and 1.05 mM. At the K concentration of the nutrient solution of 0.2 mM the single root
representing 21% of the total root weight was able to take up 47% of the 134Cs taken up by the entire root system, while at 1.05 mM the single root, representing 15% of the total root weight, took up
15% of the 134Cs taken up by the entire root system. The translocation of 134Cs from the root to the shoots did not depend on the external K concentration in the nutrient solution, but it was lower in
the split root treatment than in the control treatment at both K concentrations.
Section Editor: R. W. Bell 相似文献
17.
Spatial distribution of fruit-eating birds and fruiting shrubs of the Melastomataceae and Rubiaceae were examined on a 10 ha plot in tropical lowland wet forest of Costa Rica. Many plant species and most birds exhibited considerable spatial variation in their occurrence on the plot, as indicated by the distribution patterns of shrubs with ripe fruits and captures in mist nets, respectively. In many cases, captures of fruit-eating birds were correlated with abundance of fruiting plants, particularly for species that rely heavily on fruits. In general, fruit-eating birds concentrated their use of the plot to areas rich in fruiting shrubs. This differential use of certain areas likely results in differential visitation to fruiting plants located in these areas and in a heterogeneous dissemination of seeds into the habitat. 相似文献
18.
Dry matter production and distribution of zinc in bread and durum wheat genotypes differing in zinc efficiency 总被引:5,自引:0,他引:5
I. Cakmak N. Sari H. Marschner M. Kalayci A. Yilmaz S. Eker K. Y. Gülüt 《Plant and Soil》1996,180(2):173-181
Six bread wheat (Triticum aestivum cvs. Kiraç-66, Gerek-79, Aroona, ES 91-12, ES-14 and Kirkpinar) and four durum wheat (Triticum durum cvs. BDMM-19, Kunduru-1149, Kiziltan-91 and Durati) genotypes were grown under controlled environmental conditions in nutrient solution for 20 days to study the effect of varied supply of Zn (0 to 1 µM) on Zn deficiency symptoms in shoots, root and shoot dry matter production, and distribution of Zn in roots and shoots.Visual Zn deficiency symptoms, such as whitish-brown lesions on leaves, appeared rapidly and severly in durum wheats, particularly in Kiziltan-91 and Durati. Among the durum wheats, BDMM-19 was less affected by Zn deficiency, and among the bread wheats Kiraç-66, ES 91-12, Aroona and Gerek-79 were less affected than ES-14 and Kirkpinar.Under Zn deficiency, shoot dry matter production was decreased in all genotypes, but more distinctly in durum wheat genotypes. Despite severe decreases in shoot growth, root growth of all genotypes was either not affected or even increased by Zn deficiency. Correspondingly, shoot/root dry weight ratios were lower in Zn-deficient than in Zn-sufficient plants, especially in durum wheat genotypes.The distinct differences among the genotypes in sensitivity to Zn deficiency were closely related with the Zn content (Zn accumulation) per shoot but not with the Zn concentration in the shoot dry matter. On average, genotypes with lesser deficiency symptoms contained about 42% more Zn per shoot than genotypes with severe deficiency symptoms. In contrast to shoots, the Zn content in roots did not differ between genotypes. Shoot/root ratios of total Zn content were therefore greater for genotypes with lesser deficiency symptoms than for genotypes with severe deficiency symptoms (i.e. all durum wheat genotypes).The results suggest that the enhanced capacity of genotypes for Zn uptake and translocation from roots to shoot meristems under deficient Zn supply might be the most important factor contributing to Zn efficiency in wheat genotypes. The results also demonstrate that under severe Zn deficiency, Zn concentration in the shoot dry matter is not a suitable parameter for distinguishing wheat genotypes in their sensitivity to Zn deficiency. 相似文献
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ObjectiveThe association between zinc intake and the risk of kidney stones remains controversial. We examined the associations between dietary zinc intake, supplemental zinc intake and serum zinc levels and the prevalence of kidney stones in adults.MethodsAdult participants from the 2007–2016 NHANES were included. Restricted cubic splines were adopted to assess the dose-response relationships.ResultsDietary zinc intake was linearly associated with the prevalence of kidney stones (Pfor non-linearity = 0.50), and the odds ratios (95% confidence intervals) of kidney stones were 0.75 (0.51–1.04) for 10 mg/day, 0.65 (0.39-0.97) for 20 mg/day, 0.53 (0.30-0.94) for 30 mg/day and 0.45 (0.22-0.95) for 40 mg/day. The linear relationship was also observed among women and overweight/obese individuals. No association was found between supplemental zinc intake and the prevalence of kidney stones. A non-linear relationship was found between serum zinc levels and the prevalence of kidney stones (Pfor non-linearity = 0.02), and the odds ratios (95% confidence intervals) of kidney stones were 0.52 (0.33-0.82) for 70 ug/dL, 0.43 (0.24-0.77) for 90 ug/dL, 0.56 (0.32-0.98) for 110 ug/dL and 0.77 (0.37–1.62) for 130 ug/dL. The non-linear relationship was also observed among men and overweight/obese individuals.ConclusionsDietary zinc intake and serum zinc levels were inversely associated with the prevalence of kidney stones in adults, and there may be effect modification by participant sex and body mass index. The present analysis is limited in its ability to establish causality. 相似文献