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1.
The effects of K and Al in K-deficient and complete nutrient solutions on the growth and nutrient uptake of rice were studied in the work.The effect of Al on the growth of roots and above-ground part of rice was associated with the concentration of Al in solution .A low level(0.1 mmol L^-1) of Al promtoed but a high level(1 mmol L^-1)of Al inhibited the growth of both the root and the aerial part of rice,and the magnitude of K concentration in the nutrient solution also had an appreciable impact on this,Thus ,in the low-Al solution,the plant treated with K2(80 mg K L^-1)produced much longer roots,showing the presence of interaction between Al and K; in the high-Al solution the K-reated plant had more and longe roots and a considerably greater dry weigh of the above-ground part compared with the plant deficient in K, showing the alleviating effect of K^ on Al toxicity.The mechanism of the Al-K interaction affecting the rice aerial part growth is not yet known,but part of the reason might be that the excessive amount of Al inhibited the uptake of some nutrients such as Ca and Mg and reduced their transfer to the plant aerial organs,whereas K showed its compensating effect on this;therefore,K could relieve Al toxicity at a high level of Al and promoted rice growth at a low level of Al.  相似文献   

2.
通过冀东平原水稻土壤氮、磷、钾、锌、硼等大量和微量元素对水稻产量的影响进行研究,阐明了养分限制因子,提出了增产措施。按照NY/T 497—2002《肥料效应鉴定田间试验技术规程》,采用田间小区肥料试验方法,对氮、磷、钾、铜、铁、锰、锌、硼、钼九种营养元素进行缺素对比,找出限制因子。施用氮肥比对照增产明显,产量差异极显著,说明氮肥是影响水稻产量的主要限制因子;除氮肥外,其他肥料作用与全素比较差异不显著,说明还不是限制因子;缺氮处理与对照比产量差异不显著,说明在氮素缺失情况下,其他肥料综合作用不明显。通过对水稻营养元素限制因子的研究,初步了解了水稻生产中各种营养元素对产量的影响,为今后水稻科学施肥奠定了基础。  相似文献   

3.
There is little agreement on the leaf and shoot boron (B) requirement of rice (Oryza saliva L.) and the optimum hydroponic solution B concentration for rice. Questions on the mechanism of B uptake active or passive are also unresolved. We grew rice in hydroponic solutions in a growth chamber for six weeks with B at 0, 0.05, 0.2, 1, 5, 10, 25, and 50 μM. Transpirational flow, dry matter yields and tissue B were determined. Results indicated that B deficiency occurred when there was <7.3 mg kg‐1 B in the flag leaves, <3.6 mg kg‐1 B in shoots, and <0.2 μM B in the nutrient solutions. Boron additions increased dry matter and plant height. Typical B‐deficiency symptoms were a light color or chlorosis on almost all of the youngest leaves and stems, an unthriftiness, leaf tip burn, and pale bands 2–3 mm wide on leaves, particularly on the moderately B‐deficient plants. Whitish and twisted new leaf tips occurred at >0.05 μM B. A mass balance analysis that compared the total mass of B in the plant versus B provided via transpirational flow showed that at high hydroponic B supply, passive uptake and active excretion of B, or, active blockage of B may have occurred, for > 10‐fold differences existed between the B mass in plant and B mass that could be provided via transpirational flow. Thus, B uptake was against a concentration gradient and high B supply, and as other evidence indicated, at low B supply.  相似文献   

4.
A hydroponic experiment was carried out to study effects of chromium (Cr) stress on the subcellular distribution and chemical form of Ca, Mg, Fe, and Zn in two rice genotypes differing in Cr accumulation. The results showed that Ca, Mg, Fe, and Zn ions were mainly located in cell walls and vacuoles in roots. However, large amounts of metal ions were transferred from the vacuole to the nucleus and to other functional organelles in shoots. Chromium concentrations in the nutrient solution of 50 μM and above significantly decreased Ca concentrations in the chloroplast/trophoplast, the nucleus, and in mitochondria. It further increased Mg concentrations in the nucleus and in mitochondria, as well as Zn and Fe concentrations in the chloroplast/trophoplast. These Cr‐induced changes in ion concentrations were associated with a significant reduction in plant biomass. It is suggested that Cr stress interferes with the functions of mineral nutrients in rice plants, thus causing a serious inhibition of plant growth. The chemical forms of the four nutrients were determined by successive extraction. Except for Ca, which was mainly chelated with insoluble phosphate and oxalic acid, Mg, Zn, and Fe were extractable by 80% ethanol, d‐H2O, and 1μM NaCl. The results indicated that these low–molecular weight compounds, such as organic acids and amino acids, may play an important role in deposition and translocation of Mg, Zn, and Fe in the xylem system of rice plants.  相似文献   

5.
The subcellular distribution and chemical forms of different heavy metals in rice are correlated with their bio‐toxicity. An experiment was conducted to investigate the subcellular distribution and chemical forms of chromium (Cr) in two rice genotypes (Oryza sativa L. cv. Xiushui 113 and cv. Dan K5) differing in Cr accumulation, to understand the mechanisms of Cr toxicity and resistance in rice plants. The results show that Cr in the roots of rice plants exposed to Cr stress was mainly localized in cell walls, whereas Cr in leaves and stems was mainly present in both cell walls and vacuoles, suggesting that both compartments act as important protective barriers against Cr toxicity in rice plants. Although Cr ions in all plant tissues exist predominantly in the forms extracted by 80% ethanol and distilled water, the amount of Cr in the chemical forms extracted by 2% HAc, 0.6 M HCl, and in residues was significantly increased under the highest Cr level (100 μM Cr) compared to the plants grown under lower Cr levels. These results indicate that excess Cr accumulated in rice plants under Cr stress is bound to undissolved or low‐bioavailable compounds, such as undissolved phosphate and oxalate, being beneficial for rice plants to alleviate Cr toxicity. In addition, under the highest Cr level (100 μM), Dan K5 had a higher percentage of Cr in the chemical forms extracted by 2% HAc, 0.6 M HCl, and in residues compared to Xiushui 113 in both stems and leaves, indicating that more Cr ions in shoots of Dan K5 were bound to undissolved or low‐bioavailable compounds, in comparison with those of Xiushui 113. It is evident that the low bioavailability of Cr in the shoots of Dan K5 is related to a high Cr accumulation.  相似文献   

6.
The effects of nitrogen,phosphorus and potassium application level,seed rate and transplanting density on the growth and development of rice plants were studied to find out nutrient status in high-yielding rice plants and to increase grain yield by adequate fertilization.There was an equilibrium relationship among nutrient elements for high-yielding rice plant populations.The equilibrium index of nutrient amount ,content and distribution in high-yielding rice plants should be generally greater than-2 but less than 2.The optimum nutritive proportion of nitrogen:phosphorus:potassium assimilated by the plants was about 10:2:9 at the ripening stage.But the content and the proportion varied with the growth stages,Therefore,the nutrient in rice plant populations should be in a dynamic equilibrium.So as to achieve high yield.  相似文献   

7.
Effect of calcium and magnesium on zinc absorption by 21‐day‐old rice seedlings and its translocation within the plants was studied in the nutrient solution culture using radioactive zinc. The concentrations of the elements in the nutrient solution were 0.5, 1.0 and 2.0 μM zinc and 0, 10 and 20 mM calcium and magnesium. Absorption of 65zinc was studied for 30, 60 and 90 minutes and translocation for 24 hours. Zinc absorption increased with time and increased zinc concentration in the nutrient solutions. Addition of calcium and magnesium reduced zinc absorption by rice seedlings by about 60 and 90% respectively at a concentration of 20 mM. The nature of inhibition of both calcium and magnesium on zinc was non‐competitive as indicated by Michaelis constants. A large fraction of zinc absorbed remained in roots and only 5.3% was translocated to shoots even at 2.0 #GMM zinc concentrations in solution. The effect of cations on translocation of 65zinc within rice seedlings was more at lower( 0.5 μM zinc) than at higher (2.0 μM zinc) concentrations.  相似文献   

8.
Birch seedlings (Betula pendula) were cultivated in nutrient solution with 0–2 μM cadmium (Cd). The effects of 2–10 days of Cd exposure on root and shoot element composition [potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), molybdenum (Mo), and Cd] and growth (as percentage dry weight increase) were investigated. The element composition of fine roots and remaining root parts were analysed separately to elucidate the significance of the fine roots as a primary target for Cd toxicity. The nutrient composition of the roots was considerably altered by the Cd exposures, whereas the nutrient composition of the shoot was less affected. After eight days, the whole root (fine roots + remaining roots) concentrations of K, Ca, Mg, and Mn were reduced, whereas the opposite was found for Cu and Mo. The element distribution between fine roots and remaining roots was altered by the Cd exposures. Cadmium was accumulated in the roots and in fine roots especially. Fine roots also exhibited a capacity for Cu accumulation and a retainment of Ca and S. Total plant growth was stimulated by 0.05 μM Cd but was reduced by the 0.5–2 μM Cd treatments. Root growth was increased by the Cd exposures and growth reductions were restricted only to the shoot. Accumulation of Cd and Cu and a retainment of Ca and S in the fine roots together with a preference for root growth, imply that the explanation for the Cd effects obtained may include mechanisms for Cd tolerance.  相似文献   

9.
水稻适宜养分指标动态的知识模型研究   总被引:4,自引:0,他引:4  
在分析研究水稻栽培理论与技术资料的基础上,通过定量描述水稻群体地上部植株氮、磷、钾养分积累量和养分浓度动态与品种类型、生态环境因子和生产技术水平之间的动态关系,以生理发育时间为主线,建立了系统化和广适性的水稻适宜群体地上部植株养分指标的动态知识模型。本模型可为不同条件和产量目标下水稻栽培过程中的苗情诊断与生长调控提供定量化的养分指标动态体系。利用南京和常德2个不同生态点的常年逐日气象资料和品种资料对所建知识模型进行了实例分析,养分积累动态和养分浓度动态的RMSE分别为8.97.kg/hm2和0.32%,表明本知识模型对不同条件下的水稻植株养分指标适宜动态具有较好的预测性和指导性。  相似文献   

10.
An experiment was conducted with Phalaris aquatica L. cv. Sirolan under hydroponic conditions in the glasshouse at constant temperature of 25°C and natural sunlight. Plants were grown in double pot system with four sulfur and three molybdenum levels along with all the major‐ and micro‐nutrient elements. There was increase in growth, nitrate‐reductase activity and contents of most of the nutrient elements at all levels of sulfur and 1.68 μ/L molybdenum. Molybdenum at 3.36 μg/L level inhibited growth and nitrate‐reductase activity and decreased concentration of nutrient elements in plant. The inhibitory effect of higher level of molybdenum is perhaps mediated through its role in the nitrate‐reductase.  相似文献   

11.
A greenhouse experiment was carried out to evaluate chromium (Cr) toxicity in urograndis (Eucalyptus urophylla S. T. Blake x grandis W. Hill ex. Maiden). Chromium nitrate was amended to Clark's nutrient solution (0.00, 0.04, 0.08, 0.16, 0.32 and 0.64 mmol L?1 Cr), which was used to breed one urograndis cutting per pot (four replications). Regression analysis revealed that Cr rates of 0.08 mmol L?1 or higher significantly decreased (P < 0.01) dry matter yield of shoot and root. Chromium accumulation order in plant was: root > stem > leaves. Critical Cr toxicity level in leaves was 0.74 mg kg?1. Uptake and translocation of nutrients were affected differently by Cr. Mostly have their uptake reduced due to root damage. Magnesium, iron and manganese translocation increases, supposedly to maintain normal photosynthetic activity. Wilting is the main visual symptom of Cr toxicity. Urograndis may be suitable for contaminated sites phytostabilization and receive industrial waste fertilization.  相似文献   

12.
Rice is a staple food for more than 50% of the world's population and the majority of the global rice is produced from a lowland ecosystem. A greenhouse experiment was conducted with the objective to study lowland rice (cv. ‘BRSGO Guara’) growth, development, and nutrient uptake patterns during growth cycle. Growth observations and plant analysis were performed at initiation of tillering (IT), active tillering (AT), panicle initiation (PI), booting (B), flowering (F) and physiological maturity (PM). Plant height, number of leaves per culm, number of tillers per plant and maximum root length and root dry weight increased in a quadratic fashion with increasing plant age. Similarly, shoot dry weight increased linearly during growth cycle of the cultivar ‘BRSGO Guara’. Concentration and accumulation of most of the macronutrients and micronutrients responded with a quadratic trend with the advancement of plant age. Plant growth parameters were significantly associated with shoot dry weight plus grain yield. Similarly, nutrient accumulation had a significant correlation with shoot dry weight plus grain yield, which indicated the importance of these nutrients in the lowland rice production.  相似文献   

13.
氮磷钾配施对紫云英鲜草产量、养分含量的影响   总被引:2,自引:0,他引:2  
采用部分"3414"肥料效应试验设计方案进行田间试验,研究了氮、磷、钾配施对紫云英性状指标、鲜草产量及植株养分含量的影响,并筛选出适宜的氮、磷、钾肥用量。结果表明,施肥处理比不施肥处理,株高、茎粗、分枝、根瘤数、单株重和鲜草产量最大增幅分别为13.50%、42.34%、18.75%、18.18%、87.07%和33.22%。与不施肥处理相比,9个施肥处理紫云英鲜草产量平均增产9 591.9 kg/hm2,提高了13.50%。处理7(N0P3K2)即高量磷和中量钾配施的鲜草产量最高,达到94 641.6 kg/hm2,与不施肥处理相比,增产了33.22%。处理7对紫云英植株养分含量(N、P、K)的累积最大,与不施肥处理相比,N、P、K养分含量分别提高了16.53%、34.40%、24.47%。可见,增施磷钾肥是提高当前肥力水平下紫云英产量与植株养分累积的有效途径。合理施用N、P、K肥能明显促进紫云英的生长,提高产量和养分积累量,对翻压紫云英作绿肥,减少化肥施用量,有重要的生态环境效益。  相似文献   

14.
Abstract

The feasibility of using plant nutrient analysis results in the development of quantitative models for the evaluation and control of the nutritional status and grain yield of lowland rice was studied in a growth chamber experiment. Rice plants were grown under varying basal applications of N, P, K as well as several topdressing levels of N. Concentrations of N, P, K, Ca, Mg and Na in the above ground portions of the plants were measured four times during the growing period and at plant maturity.

Grain yield was closely related to the nutritional status of plants at 2.0 g Dry Hatter weight (DMw) per hill, as indicated by clear and reproducible relationships between the grain yield and concentrations of individual nutrient elements. Interactions between the various nutrient elements were minimum at this DMw. Therefore, 2.0 g DMw per hill was selected as a representative stage of plant development for identifying the reference values for the nutritional status of young rice plants for developing quantitative methods for the evaluation and control of nutritional status and yield.  相似文献   

15.
西双版纳热带雨林次生林的生物养分循环   总被引:15,自引:1,他引:15       下载免费PDF全文
张萍  冯志立 《土壤学报》1997,34(4):418-426
本文获得了西双版纳热带雨林,砍伐后2块处于恢复演替阶段不同年代的次生林的生物量、生长量、年凋浇物量及它们的主要营养元素含量、对土壤养分状况的影响、以及土壤微生物状况和土壤生化活性等一系列资料。阐明了次生林生物物质和养分吸收、积累和归还的特点及对土壤养发状况的影响,研究了土壤微生物对凋落物的分解作用,从而对热带雨林次生林的生物养分循环作了一初步的探讨,为热带森林生态系统研究奠定了基础。研究表明:1.  相似文献   

16.

Nutritional constraints often restrict yields of field crops in farmers’ fields. Determination of cut-off yield would increase the understanding of yield-limiting nutrients. The present study aimed to determine minimum rice yield target of high-yielding subpopulation in farmers’ fields and to identify the most limiting nutrient in farmers’ fields. Popular high yielding rice was grown in 42 farmers’ fields with two treatments – farmers’ nutrient management plan (FP) and improved nutrient management plan (INM). Nutrient composition was determined from Y-leaf after 45– 50 days of transplanting. Yield cutoff value was determined from compositional nutrient diagnosis (CND) generic model. The CND generic model gave 6.90 Mg ha?1 as minimum cutoff yield of the high-yield subpopulation. Potassium (K) was identified as the main yield limiting nutrient for rice in piedmont soils. Rice in farmers’ fields may require higher K fertilizer dose for better yield.  相似文献   

17.
Point placement of urea is an efficient technology to improve urea use efficiency in transplanted rice (Oryza sativa L.), but it is largely unknown how nutrient composition in the point placement and the distance from placement site to the plant influence rice root distribution and growth, nutrient uptake, and rice grain yield. A controlled greenhouse experiment was conducted using both N-and P-deficient soil with point placement of N only or N and P together (N + P) at a distance close to or far from the plant, in comparison to an N-spilt application and a no-N control. Both nutrient composition and distance significantly affected rice root growth. Compared with the N point placement, the N + P point placement led to smaller root length and mass densities, higher specific root length (SRL) around the placement site, smaller root system, higher straw mass and grain yield, and higher N and P uptake. The difference between the N + P and N point placements was greater when close to the plant than when far from the plant. It is suggested that higher SRL around the placement site is essential for improving nutrient uptake and rice grain yield, and simultaneous point placement of N and P has a synergistic effect on rice growth.  相似文献   

18.
为了探究不同绿肥品种之间的生长差异及其翻压后对后茬水稻养分的影响,通过选取7种不同绿肥(紫云英、白三叶草、金花菜、光叶苕子、箭筈豌豆、油菜、二月兰),以冬闲田(CK)为对照,进行大田试验,分析不同绿肥品种的生长性状、土壤肥力和水稻的产量、养分、养分累积量等指标。结果表明:不同的绿肥作物品种存在着不同的生长差异,综合来看以光叶苕子、箭筈豌豆的生物量最高,分别为46.07 t/hm2、38.74t/hm2,二者养分含量及养分累积量显著高于其他绿肥品种,适合作为苏北地区种植的绿肥品种;种植绿肥具有提高土壤肥力的潜力,促进土壤养分累积,同时对改良土壤肥力具有积极的作用。箭筈豌豆翻压后的土壤pH比CK 高出0.71%,光叶苕子翻压后有机质含量、全氮含量比CK高出1.56%、8.86%;绿肥翻压后对水稻秸秆和籽粒的氮、磷、钾含量及其累积量有了显著的增加,其中以箭筈豌豆的综合效果最好,与CK相比,箭筈豌豆翻压后水稻秸秆全氮累积量、全磷累积量分别提高15.18%、14.98%,水稻籽粒全氮累积量、全钾累积量分别提高9.98%、15.02%,水稻地上部全氮总累积量、全磷总累积量分别提高14.75%、20.42%。综上,光叶苕子、箭筈豌豆的生物量、养分累积量较高,推荐作为该地区种植的绿肥品种;光叶苕子能够对土壤肥力有一定的提高,箭筈豌豆能够促进水稻养分含量及养分累积量。研究结果可为苏北地区绿肥的利用与推广提供理论依据。  相似文献   

19.
水稻种植模式对水稻籽粒离子组的影响   总被引:2,自引:1,他引:2  
亚细胞、细胞、器官乃至有机体内所有矿质元素的组合称为离子组。离子组是植物化学元素指纹,能够定量、精准地反映环境因子驱动下植物体产生的无机化学响应。为探求不同种植模式对水稻籽粒离子组的影响,采用大田试验,研究比较了长期常规种植、绿色蛙稻和有机蛙稻3种水稻种植模式水稻籽粒中矿质元素含量的差异和元素间的相关关系,并探讨了土壤中可利用态元素向水稻籽粒中的转移效率。21种元素含量通过高通量元素分析电感耦合等离子体质谱仪(ICP-MS)测定,并利用主成分分析和方差分析等统计方法分别对数据进行综合分析和各元素处理间差异分析。结果表明,各元素在水稻籽粒中的浓度顺序为:KPMgCaMnZnFeCuRbNaBaMoBNiSrAsCrCdSeCoCs。主成分分析结果表明,不同水稻种植模式对水稻籽粒离子组有显著影响,第1主成分占总变量的32.7%,区分了有机和绿色种植模式;第2主成分占总变量的27.1%,将常规种植模式和另外两种模式区分开。不同水稻种植模式对水稻籽粒离子组有显著影响。与常规种植相比,绿色蛙稻模式下籽粒第1主族元素K、Na、Cs、Rb含量显著增加21%、31%、59%、72%,Mn、Cd的含量显著增加23%、441%,B和Cr的含量显著降低63%和51%;有机模式下水稻籽粒中Co、Ni和Cd含量分别增加60%、286%和488%,而Ca、B、Mo、Sr和Cr的含量显著降低38%、60%、20%、27%和96%,而同主族元素间的竞争并未发现。因此,从水稻必需元素吸收角度出发,绿色蛙稻种植模式优于有机和常规种植模式;但绿色和有机蛙稻种植模式对一些非必需元素的吸收也为水稻食品安全带来隐患。因此,科学的养分管理和合理种植结构的调整对保证水稻食品的安全有非常重要的意义和价值。  相似文献   

20.
Abstract

A hydroponic experiment was conducted in a phytotron at pH 5.5 to study the effects of nickel (Ni) on the growth and composition of metal micronutrients, such as copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), of barley (Hordeum vulgare L. cv. Minorimugi). Four Ni treatments were conducted (0, 1.0, 10, and 100 μM) for 14 d. Plants grown in 100 μM Ni showed typical visual symptoms of Ni toxicity such as chlorosis, necrosis of leaves, and browning of the root system, while other plants were free from any symptoms. Dry weights were the highest in plants grown in 1.0 μM Ni, with a corresponding increase in the chlorophyll index of the plants, suggesting that 1.0~10 μM Ni needs to be added to the nutrient solution for optimum growth of barley plants. The increase of Ni in the nutrient solutions increased the concentrations of Cu and Fe in roots, while a decrease was observed in shoots. The concentrations of Mn and Zn in shoots and roots of plants decreased with increasing Ni supply in the nutrient solution. Shoot concentrations of Cu, Fe, Mn, and Zn in plants grown at 100 μ M Ni were below the critical levels for deficiency. Plants grown at 1.0 μ M Ni accumulated higher amounts of Cu, Fe, Mn and Zn, indicating that nutrient accumulation in plants was more influenced by dry weights than by nutrient concentrations. The translocation of Cu and Fe from roots to shoots was repressed, while that of Mn and Zn was not repressed with increasing Ni concentration in the nutrient solution.  相似文献   

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