فاعلية الرش بالكاينتين والارجنين والحديد المخلبي في النمو والمحتوى المعدني ومحتوى المواد الفعالة طبياً لشتلات نبات النيم

The effectiveness of spraying with kinetin, arginine, and chelated iron on growth, mineral content, and medically active substances of neem seedlings

Abstract
A pot experiment was carried out in the canopy of the of Horticulture and Landscape Department – College of Agriculture – University of Kerbala during the 2023-2024 season to study the effect of kinetin (K) (0, 50, 100 mg L-1), whose symbol is (K0, K1, K2, respectively), Arginine (A) (0, 150, 300 mg L-1) and symbols (A0, A1, A2, respectively) and chelated iron (F) (200.0 mg L-1) and symbols (Fe1, Fe2, respectively) On growth, mineral content and medicinally active substances of neem seedlings. The study was implemented as a factorial experiment with a randomized complete block design with three replications. The treatments were sprayed sequentially, four sprays in the autumn, four sprays in the spring, and between one spray and another over a period of two weeks. The means were compared using least significant difference (LSD) at a probability level of 0.05%. The results showed as follows:
1- The individual treatments had varying significant effects on the studied traits, as the growth regulator kinetin affected all vegetative growth traits and most chemical traits, while the amino acid arginine had a significant effect on the stem diameter, the total carbohydrate content in the leaves, the percentage of nitrogen, phosphorus, potassium, the iron content, the total protein percentage, and the content of the types of terpenes under study. Chelated iron had a significant effect on plant height, leaf area, and some chemical traits, including carotenoids, the percentage of potassium in the leaves, and the content of Gedunin and Salania in the leaves.
2- The results showed a difference in the significant effects of the binary intervention treatments between the study factors on the studied traits, as the K2A1 interaction treatment gave the highest average plant height of 42.55 cm, while the Fe1K2 overlapping treatment gave the highest average stem diameter of 6.006 mm. The Fe2A2 intervention treatment gave the highest average number of leaves, reaching 27.87 leaf plant-1, and the Fe2A0 intervention treatment gave the highest average leaf area, reaching 988 cm2, while the K1A1 intervention treatment gave the highest average total chlorophyll content, amounting to 56.19 mg g-1 fresh weight. The Fe2A2 intervention treatment gave the highest rate of carbohydrates in the leaves, amounting to 13.31 mg g dry weight-1, while the K0A2 treatment gave the highest rate of nitrogen percentage, amounting to 3.308%. The Fe2A2 intervention treatment gave the highest rate of phosphorus, amounting to 0.1540%, while the K2A2 intervention treatment gave the highest percentage of protein reached 19.69%. The Fe1A1 interference treatment outperformed and recorded the highest average for vitamin C, amounting to 1506 mg 100 g-1. The leaf content of some terpenes was significantly affected by the interaction treatments between arginine and iron, as the Fe2A2 treatment gave the highest averages for Nimibin and Salania, reaching 2067 and 2096 µg ml-1, respectively, while the Fe1A1 treatment gave the highest averages for Azadiractin A, Nimibunal, and Gedunin, reaching 2044. 2050 (not significantly different from the Fe2A2 treatment) and 1233 µg ml-1, respectively.
3- The results of the triple intervention showed a significant effect on plant height, where the Fe2K2A2 intervention treatment gave the highest rate of 46.00 cm, and the Fe2K2A2 intervention treatment gave the highest rate of stem diameter of 6.337 mm. The Fe1K2A2 interaction treatment gave the highest average leaf area of ​​1123 cm2.