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The effect of potassium sulfate (K2SO4) on adaptability of sugarcane to sodium chloride (NaCl) stress was investigated under hydroponic conditions. Two sugarcane cultivars, differing in salinity tolerance, were grown in half strength Johnson's solution at 80 mM NaCl with 0, 2.5 and 5.0 mM potassium (K) as K2SO4. Salinity disturbed above and below-ground dry matter production in both sugarcane cultivars. However, salt sensitive cultivar showed more reduction in shoot dry matter and higher root:shoot ratio compare to the salt tolerant cultivar under. Application of K significantly (p < 0.05) improved dry matter production in both sugarcane cultivars. The concentration of Na was markedly increased with increasing salinity; however, the application of K reduced its uptake, accumulation and distribution in plant tissues. Salinity induced reduction in K concentration, K-uptake, K utilization efficiency (KUE) and K:Na ratio in both sugarcane cultivars was significantly improved with the addition of K to the saline growth medium. [ABSTRACT FROM AUTHOR]

In order to reduce nutrient wastes to the environment the supply should be in accordance to the demand for these. Two experiments were conducted to study and quantify the effect of temperature, irradiance, and plant age on the uptake of nitrate (NO3−), ammonium (NH4+), dihydrogen phosphate ion (H2PO4−), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and sulfate (SO42). In the first experiment, various levels of temperature and irradiance were applied to plants in a growth chamber, while in the second experiment the uptake was studied along the crop season under greenhouse conditions. The uptake rates were calculated at 2-hour intervals through sampling the nutrient solution and analyzing it by inductively coupled plasma atomic emission spectrometry (ICP-AES). Increasing light and temperature enhance the uptake rates, while the rates decrease with plant age. Nitrogen absorption was similar during the day as during the night. No differences were found in the absorption of H2PO4−, K+, Ca2+, Mg2+, and SO42− between day and night. Nitrate absorption was found to have a positive correlation with the absorption of all the ions except for NH4+. [ABSTRACT FROM AUTHOR]

Background: Magnesium (Mg) is pivotal for many biochemical and physiological processes in plants. Mg biological functions include a key role in photosynthesis, in protein synthesis, as well as in nucleotide metabolism. However, Mg nutrition of plants remains little examined compared with other essential elements. Scope: The review summarizes the current knowledge on physiological targets of Mg imbalances. Recently generated transcriptome profiles in response to Mg shortage and excess are also presented. Conclusions: Sugar accumulation in source leaves is a major consequence of Mg shortage that can limit plant growth most probably by down regulation of photosynthesis activity. Newly identified molecular targets of Mg imbalance are appraised in relation to their potential contribution to Mg deficiency phenotypic emergence. In particular a potential role of the circadian clock and change in phytohormones concentration and/or signalling in the orchestration of the Mg deficiency response is possible. The development of markers for incipient Mg deficiency appears to be a challenging task. [ABSTRACT FROM AUTHOR]

Nutritional imbalance under water-deficit conditions depresses plant growth by affecting nutrient uptake, transport, and distribution. The present work analyses the variations in the foliar concentrations of macro- and micronutrients as well as the transport of these nutrients in five cherry tomato cultivars under well-watered and moderately water-stressed conditions with the aim of establishing whether the ionome of the plants is related to the degree of sensitivity or tolerance to this type of stress. The results show a general reduction in growth together with a lower concentrations and uptake both of macro- as well as micronutrients in all the cultivars studied, except for cv. Zarina, which showed better growth and increased in concentrations and uptake nitrogen, phosphorus, magnesium, potassium, and chloride with respect to control plants. In conclusion, in this work, our results suggest that a better understanding of the role of the mineral elements in plant resistance to drought could improve fertilization in arid and semi-arid regions in order to increase the tolerance of plants grown under these conditions. [ABSTRACT FROM AUTHOR]

This work investigated the influence of different concentrations of calcium on the growth of plantlets of the bromeliad Aechmea blanchetiana cultured in vitro. Seedlings of A. blanchetiana were axenically cultured in liquid Murashige and Skoog basal medium supplemented with different concentrations of calcium (Ca; 1.5, 3, 4.5, 6, or 12 mM) without growth regulators. The resulting plantlets were cultured under 93 μmol m-2 s-1 illumination, 12 hour photoperiod regime and 25°C ± 1 for 120 days with subculture to fresh identical media every 30 days. The addition of calcium at 9.38 mM to MS modified medium increased the production of fresh and dry mass of plantlets, whilst chlorine from calcium chloride dehydrate (CaCl2 2 H2O) in excess (3.35 mM) decreased both the fresh and dry mass of plantlets. [ABSTRACT FROM AUTHOR]

The aim of this work, was to explore the potential of hydroponics system in Gerbera jamesonii cultivation ('Amaretto' and 'Darling' varieties), using the Steiner nutrient solution that contains 9 meq L- 1 of calcium (Ca2 +) plus two modified nutrient solutions with 6, and 12 meq Ca2 +· L- 1 on a red volcanic rock substrate known in Mexico as "tezontle",. Physiological and productivity parameters, and quality of inflorescence produced during 91 d were analyzed. Additionally, calcium in leaves, scapes, and capitula was quantified. The results showed the importance of calcium in gerbera cultivation. Calcium concentration in leaves indicated that ion assimilation was proportional to that supplied in the nutrient solution. It was found that calcium level of 6 meq Ca2 + L- 1 reduced leaf area, plant dry weight, and the number of inflorescences produced per plant during 91 d by 74% in 'Amaretto' and 61% in 'Darling' varieties with respect to the control. Likewise, this dose had effect on quality; reducing the diameter of the capitulum and scape length with respect to 9 and 12 meq Ca2 +· L- 1 The best calcium dose for 'Amaretto' was 12 meq L- 1Ca2+, and for 'Darling' 9 meq Ca2 +· L- 1, which showed the greatest dry mass weight, flower production, and quality of the inflorescence, related to high CO2 net assimilation rates. [ABSTRACT FROM AUTHOR]

When the soil in which 13-day-old barley plants were growing was flooded, the concentration of dissolved oxygen in the waterlogged soil declined to <2% (in the equilibrium gaseous phase) within 48 h. Within the same time there was injury to seminal roots and a reduction in the rate of leaf extension. The net rates of uptake of nitrogen, phosphate and potassium in shoots were reduced shortly after the onset of waterlogging, and because dry matter accumulation by shoots was initially little affected, the avenge concentration of these nutrients showed a marked decline after 48 h compared with aerated controls. The concentration of nitrate in shoots was particularly sensitive to waterlogging and after 48 h was about one third of that in controls. Analysis of individual leaves and tillers showed that with waterlogging, nitrogen was accumulated by the younger tissues at the expense of the older leaves. This trend, which was not observed with plants in aerobic soil, preceded the premature breakdown of chlorophyll in the older leaves. With prolonged anaerobiosis, there were increases in the concentration of potentially inhibitory soil products (ethylene, organic acids, manganese) and a decline in nitrate in the soil solution, but these changes, which mostly occurred after the onset of the characteristic symptoms of waterlogging damage were relatively small and unlikely to have led to injury to shoots. The possible relations between the low concentration of oxygen around roots, the inhibition of ion uptake, the redistribution of nutrients within the shoot, and the premature senescence of leaves are discussed. [ABSTRACT FROM AUTHOR]

The article presents a study which establishes the context in which Franciscus Mercurio van Helmont's experiment on essence of water in plant nutrition was performed and published and also tests the possibility that he was anticipated by other scholars. It also tries to guage that the essence of the experiment was indeed referred by another scholar Nicholas of Cusa. By access to the complete works of Nicholas of Cusa, the relevant passages were located and interpreted, and the facts of the case are summarized.