Potassium Accumulation Research Articles

Potassium accumulation characteristics and expression of related genes involved in potassium metabolism in a high-potassium variety: tobacco (Nicotiana tabacum) as a model.

We investigated potassium (K) accumulation characteristics and expression of K metabolism related genes in one high-K variety (ND202) and a common variety (NC89) of tobacco (Nicotiana tabacum L.). Results showed that K accumulation and leaf K content in ND202 were higher than those in NC89. The distribution rate and K accumulation in the leaves of ND202 increased significantly, while the distribution rate in the roots and stems had lower values. In addition, the maximum K accumulation rate and high-speed K accumulation duration in ND202 were found to be better than those in NC89. The expression of NKT1 in the upper and middle leaves of ND202 had an advantage, and the relative expression of NtKC1 and NtTPK1 in both the upper and middle leaves, as well as the roots, was also significantly upregulated. Conversely, the expression of NTRK1 in the lower leaves and roots of ND202 was weaker. ND202 had significantly greater expression levels of NtHAK1 than NC89 in the upper and middle leaves and roots; moreover, the expression of NtKT12 in the upper leaves and roots of ND202 was also higher. In comparison with common varieties, high-K varieties had a stronger ability to absorb and accumulate K. They also possessed higher expression of K+ channel- and transporter-related genes and showed a superior K accumulation rate and longer duration of high-speed K accumulation. Furthermore, K accumulation rate at 40-60days can be suggested as an important reference for the selection of high-K tobacco varieties.

Елементний склад плодів Lycopersicon esculentum Mill. за впливу технології вирощування з використанням органо-мінерального добрива «SMART» композит Марцінишин®

Mineral substances contained in vegetables perform important functions in the human body, providing protein, carbohydrate, fat, water and mineral metabolism, are components of vitamins, enzymes and proteins, regulate the physiological processes of the plant organism. The purpose of the study was to analyse the elemental composition of tomato fruits according to the culture cultivation technology using organo-mineral fertilizer. Materials for the study were the Italian hybrid of the first generation of Talent edible tomato (Lycopersicon esculentum Mill.) and organo-mineral fertilizer “SMART” Marcinyshyn composite®. The research was carried out in the soil and climatic conditions of the Western Forest Steppe of Ukraine during 2019–2021 using spectrophotometric, titrometric and atomic absorption methods. The analysis of agrochemical indicators of meadowchernozem medium loam on loess-like loam soil of experimental plots indicates its suitability for growing edible tomatoes. As a result of research, macro- (Nitrogen, Calcium, Magnesium, Potassium, Phosphorus) and microelements (Ferum, Zinc, Copper, Manganese, Boron) were found in the fruits of edible tomatoes. Organo-mineral fertilizer application in cultivation technology of Lycopersicon esculentum Mill. F1 Talent contributed to the accumulation of Nitrogen, Calcium, Potassium, Phosphorus, Zinc and Manganese in the fruits. Their number increased, respectively, by 68,5%, 12,6%, 28,3%, 85,2%, 25,8% and 56,2% compared to the control, and the accumulation of Ferum decreased by 10,3%. According to the content of Copper and Boron, the fruits of the control and experimental variants did not differ significantly from each other. The number of microelements did not exceed the maximum allowable concentrations, was within the normal range, and those microelements did not exhibit the properties of heavy metals. According to the value of the biological accumulation coefficient, the edible tomato belongs to the concentrator of Nitrogen, Phosphorus, Potassium and Copper, and the deconcentrator of Ferum, Zinc and Manganese. Due to the effect of organo-mineral fertilizer, the ripening of fruits increases in the post-harvest period.

Nutritional requirements and precise fertilization of wine grapes in the eastern foothills of Helan Mountain

Cabernet Sauvignon grapes in the wine-producing area of Helan Mountain, East Ningxia, China, were the research object in this study. The dissection of the roots and branching stems method was used to explore the dynamic changes in the nitrogen, phosphorus, and potassium nutrient requirements of wine grapes over a number of growth stages. The results showed that over the whole growth period, the nitrogen content of the roots was the highest during the leaf-expansion stage and lowest during the turning-color stage, and that the nitrogen content of the leaves and fruit showed a downward trend as growth progressed. The nitrogen content of the secondary branches was lowest during the fruit expansion stage and highest during the leaf-expansion stage; and the phosphorus content of the roots was the highest during the leaf-expansion stage and lowest during the fruit expansion stage. The phosphorus content of the trunk and primary branches showed a trend of “rising-falling-rising”. The phosphorus content of the leaves and secondary branches were lowest during the turning-color stage, whereas the phosphorus content of the fruit was at its highest during this stage. The potassium contents of the secondary branches and fruit showed a downward trend, but the potassium content of the leaves was highest during the fruit expansion stage and lowest in the nutrient return stage. Over the whole growth period, the accumulation of nitrogen, phosphorus, and potassium in wine grapes was 129.92 kg/hm2, 41.51 kg/hm2, and 189.47 kg/hm2, respectively, the total requirements for N, P2O5, and K2O were 262.38 kg/hm2, 288.15 kg/hm2, and 569.04 kg/hm2, respectively, and the reasonable nutrient requirement ratio was 1.00:1.10:2.17. Keywords: wine grapes, macronutrients, nutritional diagnosis, fertilizer requirements, the eastern foot of Helan Mountain DOI: 10.25165/j.ijabe.20221504.5406 Citation: Jiang T T, Yan P K, Ma T H, Wang R. Nutritional requirements and precise fertilization of wine grapes in the eastern foothills of Helan Mountain. Int J Agric & Biol Eng, 2022; 15(4): 147–153.

Differential accumulation of potassium in the vegetative and reproductive organs of three grapevine cultivars

Differential accumulation of potassium in the vegetative and reproductive organs of three grapevine cultivars

Statistical Indices of Land Use Changes and Nutrients Balance of Tomatoes and Peppers Production in Jordan Valley and Highlands (1999-2019)

Climate change has caused pressure on water resources in Jordan. This was accompanied by the Syrian refugee crisis during the period 2009 to 2019. This descriptive study was conducted in the University of Debrecen, during the years 2020 and 2021 within the course of sustainable land use by collecting official statistical data from reliable sources in Jordan on the production of tomato, pepper, and paprika during five years 1999, 2004, 2009, 2014 and 2019 to compare the change in land use, crop sown structure, country production, unit area average yield and estimation of unit area pollution with major nutrients. The study showed an increased land used for the production of vegetables by (+ 37.84%) during the period from 2004 to 2014, high productivity per hectare for three crops from 2014 to 2019. Jordan had the highest tomato and paprika crop yields in 2014. The reason is due to the increase in the local and global demand for these crops along with other reasons, which have promoted the use of mass production agricultural techniques, the most important of which is chemical fertilization. Which caused the accumulation of phosphorus and potassium in soils.

Deactivation by Potassium Accumulation on a Pt/TiO2 Bifunctional Catalyst for Biomass Catalytic Fast Pyrolysis

Deactivation by Potassium Accumulation on a Pt/TiO₂ Bifunctional Catalyst for Biomass Catalytic Fast Pyrolysis

The Optimal Concentration of KH2PO4 Enhances Nutrient Uptake and Flower Production in Rose Plants via Enhanced Root Growth

Monopotassium phosphate is a widely used phosphorus and potassium fertiliser for ornamental plants, but it is not known what concentration will result in optimal flower production, root growth and nutrient uptake of rose plants. We compared potted rose plants fertilised with six different concentrations (0.0 as a water-only control, 1.0, 2.0, 3.0, 4.0 and 5.0 g·L−1) of an aqueous monopotassium phosphate solution as a combination of foliar and soil applications over two consecutive flowering cycles. Rose growth, flower production and nutrient accumulation responded differently to fertilisation with different concentrations of monopotassium phosphate. During the first flowering cycle, shoot and root dry weight, leaf chlorophyll content, flower diameter, total root length and surface area, and total fine root length significantly increased in response to increased monopotassium phosphate concentrations from 0.0 to 3.0 g·L−1 but decreased in response to fertilisation with 4.0 or 5.0 g·L−1 monopotassium phosphate. Similar trends were observed in shoot dry weight, leaf chlorophyll content, flower diameter and number, phosphorus and potassium accumulation during the second flowering cycle. According to quadratic equations derived from both flowering cycles, the optimal concentration of monopotassium phosphate, based on flower diameter and dry weight, as well as total phosphorus and potassium accumulation, was 2.6–3.0 g·L−1. Furthermore, total root length was significantly correlated with flower diameter, flower dry weight, and total phosphorus and potassium accumulation (p < 0.05). These results indicated that fertilisation with optimal concentrations of monopotassium phosphate can increase rose growth, flower productivity and nutrient uptake through enhanced root growth.

A spatial-temporal understanding of gene regulatory networks and NtARF-mediated regulation of potassium accumulation in tobacco.

After tobacco topping, changes in the auxin content could affect K+ uptake by inhibiting the activity of K+ uptake-related genes through the NtARF genes, thus causing changes in K+ content. Tobacco (Nicotiana tabacum) is a valuable industrial and commercial crop, and the leaf is its primary product. Topping (removing apical buds) is a common agronomic practice that significantly improves the yield of tobacco leaves. Potassium (K+) plays an important physiological role in tobacco growth and leaf traits, including combustibility, aroma, and safety in cigarette products, and its levels are significantly decreased after topping. Here, to present global spatial-temporal gene expression profiles and gene regulatory networks of the core elements of K+ uptake, leaves and roots from topped and untopped plants at short- and long-term time points after topping were sampled for transcriptome analysis. We found that the wounding response was initiated in leaves in the early stages after topping. Then, in the long term, processes related to metabolism and transcription regulation, as well as ion binding and transport, were altered. The expression profiles showed that core elements of K+ uptake and xylem loading were drastically suppressed in roots after topping. Finally, transient expression experiments confirmed that changes in the auxin content could affect K+ uptake by inhibiting the activity of K+ uptake-related genes through the tobacco auxin response factor (NtARF) genes, thus causing changes in the K+ content. These results suggest that some ARFs could be selected as targets to enhance the expressions of K+ uptake transporters, leading to increment of K+ contents and improvement of leaf quality in tobacco breeding.

Reduced Nitrogen Rate with Increased Planting Density Facilitated Grain Yield and Nitrogen Use Efficiency in Modern Conventional Japonica Rice

The past three decades have seen a pronounced development of conventional japonica rice from the 1990s, although little information is available on changes regarding grain yield and nutrient use efficiency during this process. Nine conventional japonica rice released during the 1990s, 2000s, and 2010s were grown under a reduced nitrogen rate, with increased planting density (RNID) and local cultivation practice (LCP) in 2017 and 2018. The rice from the 2010s had 3.6–5.5% and 7.0–10.1% higher (p < 0.05) grain yield than the 2000s and the 1990s, respectively, under RNID and LCP. The harvest index contributed more to genetic yield gain from the 1990s to the 2000s; whereas from the 2000s to 2010s, yield increase contributed through shoot biomass. Genetic improvement increased total nitrogen (N), phosphorus (P), and potassium (K) accumulation, and their use efficiencies. The rice from the 2010s showed a similar grain yield, whereas the 1990s and 2000s’ rice exhibited a lower (p < 0.05) grain yield under RNID relative to LCP. RNID increased N, P, and K use efficiencies, particularly the N use efficiency for the grain yield (NUEg) of the 2010s’ rice, compared with LCP. For three varietal types, RNID increased the panicles per m2, the filled-grain percentage, and the grain weight (p < 0.05) while decreasing spikelets per panicle of the 2010s’ rice. Compared with LCP, RNID reduced non-structural carbohydrate (NSC) content and shoot biomass, at heading and maturity, while increasing the remobilization of NSC and the harvest index, especially for the 2010s’ rice. Our results suggested the impressive progressive increase in grain yield and nutrient use efficiency of conventional japonica rice since the 1990s in east China. RNID could facilitate grain yield and NUEg for modern conventional japonica rice.

Effects of cultivating different crops on soil erosion of slope farmland

The soil nutrient content, particle size composition, crop yield and erosion resistance were studied considering the slope farmland with different slope sizes and different crops as the research object. The results showed that the available phosphorus content was higher under the wheat planting mode. Rape planting was conducive to the accumulation of organic matter, total nitrogen and available potassium, and nutrient accumulation was more obvious when treated at 5° slope. The soil texture was sandy loam under the wheat planting mode. After rapeseed planting, the soil texture began to change to silt loam. The crop yield was the highest under different planting modes at 5°. Rapeseed was found to increase the soil erosion resistance of sloping farmland compared with wheat, and the greater was the slope, the stronger the erosion resistance. Bangladesh J. Bot. 50(3): 925-932, 2021 (September) Special

Effects of belowground interactions on crop yields and nutrient uptake in maize-faba bean relay intercropping systems

ABSTRACT Belowground interactions are crucial in the over-yielding of intercropping systems. However, the effects of belowground interactions on the yields of intercrops in faba bean-maize relay intercropping system are still unclear. In this study, field and pot experiments were conducted, and the biomass, yield, nutrient accumulation and photosynthetic parameters of intercrops were determined to analyze the effects of belowground interactions and relay intercropping. In the field experiments, the yield and biomass of faba bean and maize in the relay intercropping system was significantly increased compared with the monocropping. The relay intercropping promoted the accumulation of nitrogen and phosphorus in faba bean and maize but showed no effect on potassium accumulation. In the pot experiments, no barrier treatment significantly increased the nutrient accumulation of faba bean and maize, nutrient content in soil, photosynthesis, maize, yield, biomass, plant height, 100-grain weight of faba bean and maize. In summary, relay intercropping increased nutrient accumulation, photosynthesis, biomass and yield of crops. The belowground interactions of intercrops could provide good soil fertility conditions for crop growth. The results can provide references for high-yield cultivation of crops and sustainable development of agriculture.

Potassium mobilization and plant growth promotion by soil bacteria isolated from different agroclimatic zones of Odisha, India

Potassium is essential for plant metabolism; improves immunity to stress and increase crop productivity. Soil contains insoluble form of potassium, which is unavailable for plant absorption. Potash mobilizing bacteria (KMB) solubilise complex potassium and make it available to plant. KMB with plant growth promoting (PGP) traits could enhance growth and crop productivity. Here we attempt to screen KMBs with PGP traits from different agroclimatic zones of Odisha and study dynamics of potassium in soil. Isolation of KMB and determination of PGP traits was performed with standard protocols. Pot culture experiment was aimed to study their effect on sunflower crop. Available soil potassium was quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES). Thirty KMBs were isolated from different agro-climatic zones of Odisha, out of which 6 isolates exhibited maximum PGP traits. Moreover, after adding inoculums the available soil potassium decreased over 0 to 30 days as compared to control, with increase in shoot length. T7 (consortium) reported maximum (144 %) increase in shoot length. Available soil potassium content decreased with increase in time. A maximum decrease was reported in T7 (26.31 %), suggesting potassium accumulation by plant.

Potassium mobilization and plant growth promotion by soil bacteria isolated from different agroclimatic zones of Odisha, India

<p class="042abstractstekst"><span lang="EN-US">Potassium is essential for plant metabolism; improves immunity to stress and increase crop productivity. Soil contains insoluble form of potassium, which is unavailable for plant absorption. Potash mobilizing bacteria (KMB) solubilise complex potassium and make it available to plant. KMB with plant growth promoting (PGP) traits could enhance growth and crop productivity. Here we attempt to screen KMBs with PGP traits from different agroclimatic zones of Odisha and study dynamics of potassium in soil. Isolation of KMB and determination of PGP traits was performed with standard protocols. Pot culture experiment was aimed to study their effect on sunflower crop. Available soil potassium was quantified using inductively coupled plasma-optical emission spectrometry (ICP-OES). Thirty KMBs were isolated from different agro-climatic zones of Odisha, out of which 6 isolates exhibited maximum PGP traits. Moreover, after adding inoculums the available soil potassium decreased over 0 to 30 days as compared to control, with increase in shoot length. T7 (consortium) reported maximum (144 %) increase in shoot length. Available soil potassium content decreased with increase in time. A maximum decrease was reported in T7 (26.31 %), suggesting potassium accumulation by plant.</span></p>

Correction to: Nano-Silicon Complexes Enhance Growth, Yield, Water Relations and Mineral Composition in Tanacetum parthenium under Water Deficit Stress

Developing methods and approaches for preserving water relations, plant growth and productivity are essential under water deficit conditions. New nano-silicon complexes were synthesized (glycine nano-silicon, glutamine nano-silicon and histidine nano-silicon) to evaluate their foliar application in different concentrations (0, 1.5 and 3.0 mM) on growth, essential oil yield, water relations, and mineral composition of field grown feverfew (Tanacetum parthenium L.) under drought. Drought stress was imposed by different irrigation intervals (4, 8 and 12 days). By increasing irrigation interval, leaf relative water content and leaf water potential were declined which decreased biomass, leaf area, flower formation, essential oil production and health of the plant. Potassium and organic osmolytes accumulation under moderate drought stress alleviated the adverse effects water deficit condition. This was mainly due to proline and potassium accumulation in the plants’ leaves. Although accumulation of soluble carbohydrates also was observed in the drought stressed plants, it was found to be a passive response to plant growth inhibition under drought. Moreover, drought stress decreased plant phosphorous content, but had no significant effect on plant nitrogen content. Foliar application of nano-silicon by improving the plant’s water content and phosphorus absorption, recovered the plants’ health and growth under moderate and severe drought conditions. In this regard, no significant differences were observed between 1.5 and 3.0 mM nano-silicon treatments. However, glycine nano-silicon treated plants represented higher drought tolerance (higher dry mass, leaf area, number and greenness) than the other complexes. Accordingly, foliar application of 1.5 mM glycine nano silicon for mitigating adverse effects of drought stress on feverfew was recommended.

Initiation and entrainment of multicellular automaticity via diffusion limited extracellular domains

Electrically excitable cells often spontaneously and synchronously depolarize in vitro and in vivo preparations. It remains unclear how cells entrain and autorhythmically activate above the intrinsic mean activation frequency of isolated cells with or without pacemaking mechanisms. Recent studies suggest that cyclic ion accumulation and depletion in diffusion-limited extracellular volumes modulate electrophysiology by ephaptic mechanisms (nongap junction or synaptic coupling). This report explores how potassium accumulation and depletion in a restricted extracellular domain induces spontaneous action potentials in two different computational models of excitable cells without gap junctional coupling: Hodgkin-Huxley and Luo-Rudy. Importantly, neither model will spontaneously activate on its own without external stimuli. Simulations demonstrate that cells sharing a diffusion-limited extracellular compartment can become autorhythmic and entrained despite intercellular electrical heterogeneity. Autorhythmic frequency is modulated by the cleft volume and potassium fluxes through the cleft. Additionally, inexcitable cells can suppress or induce autorhythmic activity in an excitable cell via a shared cleft. Diffusion-limited shared clefts can also entrain repolarization. Critically, this model predicts a mechanism by which diffusion-limited shared clefts can initiate, entrain, and modulate multicellular automaticity in the absence of gap junctions.

ZRT-IRT-Like PROTEIN 6 expression perturbs local ion homeostasis in flowers and leads to anther indehiscence and male sterility.

Metallic micronutrients are essential throughout the plant life cycle. Maintaining metal homeostasis in plant tissues requires a highly complex and finely tuned network controlling metal uptake, transport, distribution and storage. Zinc and cadmium hyperaccumulation, such as observed in the model plant Arabidopsis halleri, represents an extreme evolution of this network. Here, non-ectopic overexpression of the A. halleri ZIP6 (AhZIP6) gene, encoding a zinc and cadmium influx transporter, in Arabidopsis thaliana enabled examining the importance of zinc for flower development and reproduction. We show that AhZIP6 expression in flowers leads to male sterility resulting from anther indehiscence in a dose-dependent manner. The sterility phenotype is associated to delayed tapetum degradation and endothecium collapse, as well as increased magnesium and potassium accumulation and higher expression of the MHX gene in stamens. It is rescued by the co-expression of the zinc efflux transporter AhHMA4, linking the sterility phenotype to zinc homeostasis. Altogether, our results confirm that AhZIP6 is able to transport zinc in planta and highlight the importance of fine-tuning zinc homeostasis in reproductive organs. The study illustrates how the characterization of metal hyperaccumulation mechanisms can reveal key nodes and processes in the metal homeostasis network.

Improving Unmanned Aerial Vehicle (UAV) remote sensing of rice plant potassium accumulation by fusing spectral and textural information

Plant potassium accumulation (PKA) plays an important role in evaluating the production capacity of crops. Remote sensing from unmanned aerial vehicles (UAVs) is increasingly used in precision agriculture, but relatively little is known about its use for determining the potassium (K) nutritional status of rice (Oryza sativa L.). This study compares the performance of different sets of spectral and textural indices derived from UAV data for estimating rice K nutritional status. A UAV equipped with three cameras (RGB, color-infrared (CIR) and multispectral cameras) was used to acquire imagery of rice canopies at different key growth stages. Immediately following the overflights, rice canopies were sampled for rice PKA. Regression models were then built to predict rice PKA with spectral and textural indices as predictor variables. Finally, stepwise multiple linear regression (SMLR) was used to determine if fusing spectral and textural indices significantly improved UAV-based PKA estimates. The renormalized difference vegetation index (RDVI) calculated from multispectral imagery proved to be the best predictor of rice PKA (R2 = 0.72, RMSE = 5.42 g m−2), though spectral vegetation indices calculated from RGB and CIR imagery also showed moderately strong prediction capability (R2 ≤ 0.56, RMSE ≥ 7.33 g m−2). Among the textural indices, the renormalized difference texture index [RDTI (MEA800, MEA680)] calculated by mean texture (MEA) of the multispectral imagery was the best predictor of rice PKA (R2 = 0.74, RMSE = 5.57 g m−2) while textural indices calculated from the RGB and CIR imagery showed only weak relationships with rice PKA (R2 ≤ 0.40, RMSE ≥ 8.11 g m−2). Fusing textural and spectral vegetation indices improved our ability to remotely sense PKA, with the SMLR model combination of RDTI (MEA800, MEA680) and spectral vegetation index DATT performing best (R2 increased by 11.11% to 0.80 and RMSE decreased by 7.5% to 5.15 g m−2). Our findings suggest that spectral and textural indices derived from UAV data allow for accurate mapping of PKA and that fusion of the two further improves the accuracy.

Brain extracellular space of the naked mole-rat expands and maintains normal diffusion under ischemic conditions

Brain extracellular space (ECS) forms a conduit for diffusion, an essential mode of molecular transport between brain vasculature, neurons and glia. ECS volume is reduced under conditions of hypoxia and ischemia, contributing to impaired extracellular diffusion and consequent neuronal dysfunction and death. We investigated the ECS volume fraction and diffusion permeability of the African naked mole-rat (NM-R; Heterocephalus Glaber), a rodent with a remarkably high tolerance for hypoxia and ischemia. Real-Time Iontophoretic and Integrative Optical Imaging methods were used to evaluate diffusion transport in cortical slices under normoxic and ischemic conditions, and results were compared to values previously collected in rats. NM-R brains under normoxic conditions had a smaller ECS volume fraction than rats, and a correspondingly decreased diffusion permeability for macromolecules. Surprisingly, and in sharp contrast to rats, the NM-R ECS responded to ischemic conditions at the center of thick brain slices by expanding, rather than shrinking, and preserving diffusion permeabilities for small and large molecules. The NM-R thick slices also showed a blunted accumulation of ECS potassium compared to rats. The remarkable dynamic response of the NM-R ECS to ischemia likely demonstrates an adaptation for NM-R to maintain brain function in their extreme nest environment.

Ions and Organic Solutes as Implicated in the Ameliorative Effect of Exogenous Application of Calcium on Salt Stressed Tomato (Lycopersicon esculentum Mill.) Plants

Aims: This study evaluated the role of sodium, potassium, proline and soluble sugars accumulation in the ameliorative effect of an exogenous application of calcium on the detrimental effect of salinity on tomato plants.
 Study Design: The experiment was implemented as a Completely Randomized Design (RCD) with four treatments and three replications.
 Place and Duration of Study: The experiment was realized in a green house of the Faculty of Agronomical Sciences, University of Abomey-Calavi, Benin Republic from June to July 2020. Methodology: Three weeks old plants of the tomato cultivar “Padma” was submitted in pots to four treatments comprising the control (without NaCl); salt stress (120 mM NaCl) and a combination of 120 mM NaCl and exogenous application of 40 mM CaSO4 or Ca (NO3)2 by irrigation every two days. Plants growth, sodium (Na) and potassium (K) as well as proline and soluble sugars contents of leaves and roots were determined after two weeks.
 Results: Salt effect reduced significantly plant growth at P =.05, root K content at P =.05 and leaf K/Na ratio at P =.01 whereas it increased significantly leaf Na at P =.05 and root soluble sugars content at P =.05. The application of exogenous calcium (Ca) induced a significant amelioration of plant growth at P =.01 more marked with CaSO4 than with Ca (NO3)2. This treatment induced a significant decrease at P =.01 in leaf and root Na content and a significant increase at P =.05 in root K content only for CaSO4, a significant increase at P =.01 in leaf K/Na ratio and a significant increase at P =.01 in leaf and root proline content only for Ca(NO3)2.
 Conclusion: The ameliorative effect of both forms of calcium was due mainly to sodium (Na) exclusion from leaves and potassium (K) accumulation associated to a maintain of high K/Na ratio mainly in leaves. The importance of proline accumulation as an indicator of this ameliorative effect was associated only to Ca(NO3)2.

Effect of Different Substrates on Growth and Nutrient Absorption of Cinnamomum chekiangense Seedlings

Cinnamomum chekiangense is an important and precious tree species. In vigorously promoting precious tree species for the afforestation, the cultivation of high-quality container seedlings is the key to the success of afforestation, and the seedling substrate directly determines the quality of seedlings. In this paper, 1-year-old seedlings of C. chekiangense were selected as the research object, using potted culture method to study the effects of 5 substrates (yellow soil, sawdust, peat) on seedling plant height, ground diameter, biomass growth and accumulation of nitrogen, phosphorus and potassium, in order to screen out the suitable substrate ratio for the cultivation of the container seedlings of the C. chekiangense and provide the basis for the cultivation of high-quality container seedlings. The results showed that A3 (yellow soil∶peat∶sawdust=40∶30∶30) substrate was most conducive to the growth of C. chekiangense, and the plant height and ground diameter were significantly higher than A5 (P<0.05). The leaves, branches, roots and total biomass of C. chekiangense cultivated with A3 substrate were largest, which were 33.63, 39.57, 48.43, 121.64 g·plant−1, respectively; significantly higher than other treatments (P<0.05). The accumulation of nitrogen, phosphorus, and potassium in the whole plant of C. chekiangense cultivated with A3 substrate were the best, which were 3168.8, 137.3, 673.1 mg·plant−1 respectively; Gray correlation analysis method evaluation showed that A3 substrate was the best substrate for the growth of the C. chekiangense container seedlings.