Plant Nutrition
Farnaz Kargar; Abbas Mirsoleimani; Mahdi Najafi-Ghiri
Abstract
Purpose: Nitrogen (N) plays a crucial role in citrus growth, but its deficiency or excess can disrupt nutrient balance and physiological functions in plant. This study investigated how varying N levels (2, 4, 8, 16, and 32 mM) affect growth, photosynthesis, root morphology and nutrient interactions in ...
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Purpose: Nitrogen (N) plays a crucial role in citrus growth, but its deficiency or excess can disrupt nutrient balance and physiological functions in plant. This study investigated how varying N levels (2, 4, 8, 16, and 32 mM) affect growth, photosynthesis, root morphology and nutrient interactions in sour orange (Citrus aurantium L.) seedlings. Research Method: Seedlings were grown in nutrient solutions with different N concentrations. Biomass, photosynthetic efficiency (Fv/Fm, PI), chlorophyll content, nutrient uptake, and nitrate reductase activity were analyzed. Findings: Maximum and significant plant dry weight (4.95 g), root length (51.5 cm), chlorophyll content (8.6 mg g⁻¹ FW), and photosynthetic efficiency (Fv/Fm = 0.73; PI = 4.2) occurred at 16 mM N compared to 2 mM N. In contrast, N deficiency (2–8 mM) reduced growth and photosynthetic performance, while N toxicity (32 mM) decreased plant biomass by 50%, impaired chlorophyll synthesis, and disrupted photosystem II efficiency (Fv/Fm = 0.55). Excessive N (32 mM) altered nutrient homeostasis, increasing root Ca and K concentration by 0.82% and 2.49% respectively but reducing their translocation to shoots, elevating the Ca/K ratio a key indicator of K deficiency risk in calcareous soils. Nitrate reductase activity declined under toxicity, reflecting suppressed N assimilation. Root N/Ca ratio decreased with increasing in N concentration and Ca/K ratio of root in N16 and N32 treatments was higher than that in other N treatments. Phenolic compounds accumulated in roots under high N, suggesting oxidative stress mitigation. Research limitations: No limitations were found. Originality/Value: Excessive N disrupts nutrient balance, photosynthetic inhibition, and growth suppression while 16 mM N optimizes sour orange growth.
Plant Nutrition
Abbas Mirsoleimani; Mahdi Najafi-Ghiri; Hamid-Reza Boostani; Hossein Heydari
Abstract
Purpose: It is believed that wood vinegar (WV) can improve soil nutrient availability and uptake, thereby improving plant growth and development. In this study we investigate the effect of WV on the availability of macro- and micro elements in the soil and the uptake, translocation and efficiency of ...
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Purpose: It is believed that wood vinegar (WV) can improve soil nutrient availability and uptake, thereby improving plant growth and development. In this study we investigate the effect of WV on the availability of macro- and micro elements in the soil and the uptake, translocation and efficiency of these elements in seedlings of sour orange (SO) and Mexican lime (ML) as well as on plant growth. Research method: The applied WV (1 and 2%) (v/v) was added to the irrigation water at intervals of 3, 6, 9 and 12 weeks after planting. Findings: The results showed that the use of WV at both concentrations reduced the phosphorous (P) and potassium (K) concentration in the leaves of ML, reduced the percentage of calcium (Ca) uptake and efficiency of copper (Cu) in SO and increased the iron (Fe) in ML root (1150 to 1320 mg kg-1 DW). Although 1% WV increased soil availability of Ca, sodium (Na), zinc (Zn) and manganese (Mn) and thus decreased root K/Na and Ca/Na, WV 2% improved Mn and K availability but decreased Ca in the soil solution. Application of 1 and 2% WV reduced root dry weight by 16.1 and 12.9% in SO seedling, respectively and in ML seedlings 2% WV reduced total chlorophyll and leaf greenness. Research limitations: No limitations were found. Originality/Value: The results showed that although the addition of WV to the soil can reduce the pH and thereby increase the availability of some elements such as K and Mn, the increase in EC prevents the effective absorption and translocation of elements and thus plant growth such as root dry weight and greenness.
