Calcium Regulates Growth and Nutrient Absorption in Poplar Seedlings

Abstract

As a crucial element for plants, calcium (Ca) is involved in photosynthesis and nutrient absorption, and affects the growth of plants. Poplar is an important economic forest and shelter forest species in China. However, the optimum calcium concentration for its growth is still unclear. Herein, we investigated the growth, biomass, photosynthetic pigments, photosynthetic parameters and products, chlorophyll fluorescence parameters, water use efficiency (iWUE), and antioxidant enzyme activity of “Liao Hu NO.1” poplar (P. simonii × P. euphratica) seedlings at 0, 2.5, 5, 10, and 20 mmol·L−1 concentrations of Ca2+, and further studied the absorption, distribution, and utilization of nutrient elements (C, N, P, K, and Ca) in plants. We found that with increasing calcium gradient, plant height and diameter; root, stem, leaf, and total biomasses; net photosynthetic rate (Pn); stomatal conductance (Gs); intercellular carbon dioxide (Ci) level; transpiration rate (Tr); Fv/Fm ratio; Fv/F0 ratio; chlorophyll-a; chlorophyll-b; soluble sugar and starch content; superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) levels; and long-term water use efficiency (iWUE) of poplar seedlings first increased and then decreased. These parameters attained maximum values when the calcium concentration was 5 mmol·L−1, which was significantly different from the other treatments (P < 0.05). Moreover, a suitable Ca2+ level promoted the absorption of C, N, P, K, and Ca by various organs of poplar seedlings. The absorption of C, N, P, and K increased first and then decreased with the increased calcium concentration, but the optimum calcium concentrations for the absorption of different elements by different organs were different, and the calcium concentration in leaves, stems, and roots increased gradually. Furthermore, the increase in exogenous calcium content led to a decreasing trend in the C/N ratio in different organs of poplar seedlings. C/P and N/P ratios showed different results in different parts, and only the N/P ratio in leaves showed a significant positive correlation with Ca2+ concentration. In conclusion, the results of this study indicate that 5 mmol·L−1 concentration of Ca2+ is the optimal level, as it increased growth by enhancing photosynthesis, stress resistance, and nutrient absorption.

Integrative organic fertilizer immobilized in marine waste derived CaCO3 nanocarrier system towards quality and quantity enhancement of tomato cultivation

“…The calcium regulates the stomatal movement and proteins of photosynthesis of plants along with enhanced nutritional uptake. [42][43] In this work, the CaCO 3 nanoparticles and panchakavya extract can release the calcium ions signi cantly to the plant along with the NPK and growth regulators present in the panchakavya extract. The azadirachtin in the nanofertilizer formulation was helpful for the optimized solubility and enhanced protection from the pest attack.…”

Optimal exogenous calcium alleviates the damage of Snow-melting agent to Salix matsudana seedlings

“…Then the samples were dried to a constant weight of 65°C. The biomass of Salix matsudana seedings was determined by an analytical balance with an accuracy of 0.001 g ( Li et al, 2022 ; Weng et al, 2022 ).…”

“…A modified Arnon (1949) method, in which the absorption of light at wavelengths of 665 nm, 649 nm, and 479 nm of the cleaning solution was recorded, was used to determine the carotenoid, chlorophyll a, and chlorophyll b contents. The pigment contents were calculated according to the following equations ( Li et al, 2022 ; Weng et al, 2022 ):…”

Targeted Metabolome and Transcriptome Analyses Reveal the Pigmentation Mechanism of Hippophae (Sea Buckthorn) Fruit

“…The chlorophylls were extracted from frozen fruit with 95% ethanol, and the light absorbance values of the extracts were determined at 649 and 665 nm using a spectrophotometer. The chlorophyll concentration in 95% ethanol was calculated as chlorophyll a Ca (mg/L) = 13.95A 665 − 6.88A 649 , chlorophyll b Cb (mg/L) = 24.96A 649 − 7.32A 665 , total chlorophyll C = Ca + Cb [ 32 , 33 ]. The chlorophyll content in the fruit (mg/kg) = C × Volume of chlorophyll extract (L)/Weight of fruit (kg).…”