Conditions Of Ca Deficiency Research Articles

Role of calcium as a possible regulator of growth and nitrate nitrogen metabolism in apple dwarf rootstock seedlings

As a crucial element for plants, calcium (Ca) is involved in both nitrogen (N) absorption and assimilation. Plants tend to exhibit lower nitrogen use efficiency (NUE) under Ca-deficient conditions. Improving NUE in apple production can reduce the negative effects of the excessive use of N fertilizer. However, the role of Ca in the regulation of nitrate uptake and reduction remains unclear. Herein, we investigated the growth response and nitrate (NO3−) metabolism of apple dwarf rootstock seedlings (M9T337) for Ca2+ concentrations of 0, 2, 4, 6, 8, 10, and 12 mM Ca2+ using 15N isotope labeling tracer, non-invasive micro-testing technology, and quantitative real-time polymerase chain reaction (qrt-PCR). Results showed that Ca accumulation rate in the plant tissue increased with increasing Ca supply levels; however, the plant biomass, photosynthesis, root activity, and 15NUE peaked for 6 mM of Ca2+ supply. Further investigation revealed that for 6 mM of Ca2+ supply, nitrate reductase (NR) activities were relatively high, the transcription of nitrate transporter (MdNRT1.1; MdNRT2.1) up-regulated and NO3− maximum influx rate in the roots occurred. Furthermore, seedlings treated with 6 mM Ca2+ had a significantly lower NO3- concentration in leaves and roots, a higher NH4+ concentration in leaves, and a higher amino acid compounds concentration. Moreover, both Ca deficiency and excessive Ca inhibit N absorption and utilization, and the adverse effects of Ca deficiency on seedling growth and N metabolism were greater than those associated with excessive Ca2+ supply. Conclusively, the results of this study indicate that appropriate Ca2+ supply (6 mM) was optimal as it increased NUE by enhanced photosynthesis, N metabolizing enzyme activities, NO3− uptake and transport.

Impact of SO2 on Alteration of Reservoir Rock with Ca-Deficient Conditions and Poor Buffering Capacity under a CO2 Geologic Storage Condition

The objective of this study is to evaluate the impact of SO2-CO2-water-rock interaction on the alteration of a reservoir rock having Ca-deficient conditions and little buffering capacity and its implication for porosity change near the injection well from a CO2 storage pilot site, Republic of Korea. For our study, three cases of experimental and geochemical modeling were carried out (pure CO2, 0.1% SO2 in CO2, and 1% SO2 in CO2, resp.) under realistic geologic storage conditions. Our results show that SO2 accelerated water-rock interactions by lowering the pH. In the 1% SO2 case, pH remained less than 2 during the experiments because of insufficient buffering capacity. Sulfate minerals were not precipitated because of an insufficient supply of Ca. Because the total volume of precipitated secondary minerals was less than that of the dissolved primary minerals, the porosity of rock increased in all cases. Chlorite largely contributed to the decrease in total rock volume although it formed only 4.8 wt.% of the rock. Our study shows that the coinjection of a certain amount of SO2 at CO2 storage reservoirs without carbonate and Ca-rich minerals can significantly increase the porosity by enhancing water-rock interactions. This procedure can be beneficial to CO2 injection under some conditions.

Pseudomonas sp. LSW25R, antagonistic to plant pathogens, promoted plant growth, and reduced blossom-end rot of tomato fruits in a hydroponic system

A Gram-negative rhizobacterial isolate (LSW25) antagonistic to Pseudomonas corrugata, a vein necrosis pathogen of tomato, and promotes the growth of tomato seedlings was isolated from surface-sterilised tomato roots. A spontaneous rifampicin-resistant mutant (LSW25R) was selected to facilitate its tracking, and identified as Pseudomonas sp. and named as Pseudomonas sp. LSW25R (LSW25R), based on its sequences of the internal transcribed spacer (ITS) region and 16 S rRNA gene. LSW25R inhibited mycelial growth of 12 other plant fungal pathogens such as Botrytis cinerea on V8 agar plates. By using a scanning electron microscope, LSW25R colonised not only the root surface around the natural aperture of tomato radicles but also under epidermal cells like endophytic bacteria. LSW25R successfully colonised the roots of tomato, eggplant and pepper seedlings, significantly promoted the fresh weight, height and dry matter of tomato plants at 108 cfu·ml−1, and increased the plant growth of eggplants and peppers at 104 cfu·ml−1, suggesting that the optimal population density of LSW25R for growth promotion varies from species to species. Moreover, densities of LSW25R inside roots and the lowest leaf of tomato plants were > 9.3 × 103 cfu·g−1. Although the growth promotion of tomato by LSW25R was observed under N- or Ca-deficient conditions as well as a standard nutrient condition, the uptake of calcium was increased only under the standard nutrient condition. In a hydroponic system, LSW25R not only successfully colonised the rhizosphere during cultivation due to its broad spectrum of antifungal activity and endophytic colonisation, but also reduced blossom-end rot of tomato fruits presumably through increasing calcium uptake.

Calcium, snails, and birds: a case study

Abstract. Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

Reproductive response of Great Tits, Parus major, in a naturally base-poor forest habitat to calcium supplementation

Recent studies have revealed that some forest passerines have difficulty obtaining sufficient calcium (Ca) for their eggshells in heavily acidified areas. However, the effect of Ca limitation on breeding success in non-acidified but naturally base-poor breeding habitats is not yet clear. The issue itself is important, insofar as the cost of egg formation in a certain habitat depends on the availability not only of energy and proteins but also of shell-formation material. We studied the effect of experimental supplementation with extra Ca on the reproductive output of Great Tits, Parus major, breeding in base-poor pine forests in Estonia. Pairs provided with Ca started egg laying earlier than control pairs, and clutch volume was larger in Ca-supplemented nests. There was also a positive effect of Ca supplementation on fledglings' tarsus length and body mass in the year when breeding conditions were the most unfavorable. However, no significant differences were found between the experimental and control groups in hatching success or number of fledglings. We suggest that Ca deficiency is a less limiting factor in naturally base-poor forests than in highly acidified areas, and that birds are able to adjust their breeding efforts to conditions of Ca deficiency. Great Tits, for instance, may respond to Ca shortage by postponing egg laying until their body condition and rate of food intake reach a critical threshold for producing viable eggs and young.

Reproductive response of Great Tits, <i>Parus major</i>, in a naturally base-poor forest habitat to calcium supplementation

Recent studies have revealed that some forest passerines have difficulty obtaining sufficient calcium (Ca) for their eggshells in heavily acidified areas. However, the effect of Ca limitation on breeding success in non-acidified but naturally base-poor breeding habitats is not yet clear. The issue itself is important, insofar as the cost of egg formation in a certain habitat depends on the availability not only of energy and proteins but also of shell-formation material. We studied the effect of experimental supplementation with extra Ca on the reproductive output of Great Tits, Parus major, breeding in base-poor pine forests in Estonia. Pairs provided with Ca started egg laying earlier than control pairs, and clutch volume was larger in Ca-supplemented nests. There was also a positive effect of Ca supplementation on fledg- lings' tarsus length and body mass in the year when breeding conditions were the most unfavorable. However, no sig- nificant differences were found between the experimental and control groups in hatching success or number of fledglings. We suggest that Ca deficiency is a less limiting factor in naturally base-poor forests than in highly acidified areas, and that birds are able to adjust their breeding efforts to conditions of Ca deficiency. Great Tits, for instance, may respond to Ca shortage by postponing egg laying until their body condition and rate of food intake reach a critical threshold for producing viable eggs and young.

Effect of Potassium, Magnesium, and Calcium Deficiencies on Nitrogen Constituents and Chloroplast Components in Citrus Leaves

The chlorotic appearance of mineral-deficient citrus leaves presumably reflects degradative changes in chloroplast components, most of which have nitrogen as a principal constituent. To examine this assumption the size of some major nitrogen pools, the SDS-PAGE pattern of soluble and chloroplast membranal proteins, and the activities of nitrate reductase and ribulose bisphosphate carboxylase (RuBPcase) were determined in leaves of rough-lemon (Citrus volkameriana Ten. & Pasq) plants grown hydroponically for 3 to 10 months under K, Mg, and Ca deficiencies. Plants grown under minerally deficient conditions produced less biomass. Leaves developing under K, Mg, and Ca-deficient conditions had significantly reduced concentrations of the respective elements. Chlorophyll levels of the chlorotic Mg and Ca-deficient leaves were lower than those of control leaves but chlorophyll a/b ratios were not markedly different. Calcium deficiency caused significant decreases in total nitrogen, nitrates, and the free amino acid pool. Proline which is the major component of the free amino acid pool decreased by 82.5%. Calcium-deficient leaves had significantly lower nitrate reductase and RuBPcase activities. The level of RuBPcase holoenzyme and its subunits were also reduced. Protein levels of K, Mg, and Ca-deficient leaves were not significantly altered. The SDS-PAGE patterns of soluble and chloroplast membranal proteins did not reveal major qualitative changes. In conclusion, the data do not demonstrate a general close link between chlorosis of minerally deficient citrus leaves and nitrogen metabolism. Calcium deficiency seems to specifically interfere with early stages of nitrogen assimilation and free amino acid accumulation but the metabolic integrity of the leaf is apparently maintained even under severe nutritional stress conditions.

Deficiency of N, P, K, Ca, Mg, or Fe Mineral Nutrients inNarcissuscv. “Garden Giant”

Abstract Narcissus cv. “Garden Giant” bulbs were grown in N, P, K, Ca, Mg, or Fe-deficient solutions and compared with bulbs grown in the control solution containing all these nutrients. Plants were sampled at 4 stages: (I) at planting, (II) at sprouting, (III) after flower senescence and/or after visible deficiency symptoms developed, and (IV) at lifting. Observation of visible deficiency symptoms showed that leaves of narcissus displayed chlorosis in the —N, —Mg, and —Fe treatments, while roots were most susceptible to Ca-deficient conditions. Root tips in the —Ca treatment showed brown in followed by root rot. In the —N treatment, shoot growth was markedly retarded and leaves were small and yellow. On the other hand, visible deficiency symptoms were not evident in the —P treatment except for early senescence. K deficiency symptoms were also not evident. Narcissus flowers were not affected by the mineral deficiencies and mineral contents in full-bloom flowers were not different between samples. In the c...

Ferredoxin-dependent glutamate synthase activity during the first developmental stages of wheat plants as affected by calcium deficiency

The delay in development of winter wheat plants grown under conditions of Ca deficiency manifested itself also in the time curve of ferredoxin-dependent glutamate synthase activity. Up to the stage of the first leaf the activity increased. Thereafter it gradually decreased similarly as under conditions of complete nutrition, but with a shift of about 7 days as compared with plants given complete nutrition. Increased glutamate synthase activity in Ca-deficient plants may be one of the factors leading to a high glutamate level under these conditions.

Calcium-dependent slow action potentials in potassium-depolarized guinea-pig ventricular myocardium enhanced by barium ions.

Experiments were performed to investigated the mechanism by which Ba ions facilitate slow response in the myocardium. In partially depolarized guinea-pig papillary muscles, adding 0.2 mmol/l Ba to K-rich solution drastically lowered the stimulus threshold and converted the graded response to an all-or-none activity. This change was accompanied by an increase in the membrane resistance, as determined by cable analysis. When [Ca]0 was altered (0.9--7.2 mmol/l) in the presence of 0.2 mmol/l Ba, the action potentials varied almost in a manner expected for a Ca-electrode, and there were concomitant increases in the twitch tension. The electrical and mechanical activities of muscles treated with 1 mmol/l Ba were also strongly Ca-dependent. At normal [Ca]0, increasing [Ba]0 from 0.2--1 mmol/l only slightly enhanced the action potentials without any appreciable change in the peak twitch tension. When [Ca]0 was lowered to 0.2 mmol/l, elevation of [Ba]0 to over 0.5 mmol/l restored the action potentials, and the resting tension increased. These results suggest that the facilitatory action of the low concentration of Ba on the Ca-dependent slow action potentials is due to a reduction in the membrane shunting conductance and not to a development of any sizeable inward Ba current. However, Ba-dependent action potentials may be generated under conditions of Ca-deficiency. Isoprenaline (0.5--5 x 10(-7) mol/l) induced an automatic activity in the Ba-treated muscles and this phenomenon is probably related to both the drug-induced increase in Ca-permeability and the Ba-induced decrease in shunting conductance. Thus Ba ions appear to be a feasible tool for studies on the myocardial slow channel.

Cell Wall Properties of Cotton Roots as Influenced by Calcium and Salinity1

AbstractResearch was conducted to determine the influences of salinity and Ca uptake on cell wall properties of cotton (Gossypium hirsutum L.) roots. It was postulated that examination of cell wall properties might give insight on the role of Ca in moderating the influences of salinity and toxic ions on cellular stability and plant growth. Age and Ca are essential to the development of thick cell walls in the stele. Thick cell wails exhibit high birefringence under polarized light. Salinity reduced Ca uptake and concentration of cotton roots. Xylem and phloem cell walls of cotton roots grown in solutions with sufficient Ca and low salinity thickened and in about 70 hours, exhibited high birefringence. Young cell walls in the pericycle or laterals did not exhibit birefringence. Even at adequate level of Ca, salinity retarded the development of thick cell walls and high birefringence in the stele to about 140 hours. The time required to develop thick cell walls may determine cellular stability or breakdown. The birefringent properties of certain plant parts seem to offer opportunities to study cellular disorders in plants due to the stress conditions of Ca deficiency or salinity.