The effect of supplemental irrigation, salicylic acid and humic acid foliar spraying on the response of photosynthetic pigments (chlorophyll a, chlorophyll b and chlorophyll total) and the amount of absorption of nutrients of the Dragon's head (Lal

The objective of this study was to investigate the effects of supplementary irrigation and foliar spraying with salicylic acid and humic acid on the biochemical properties of dragon's head (Lallemantia iberica) under Khorramabad climatic conditions at Visian Research Station. The experiment was conducted as a split-plot-factorial based on a randomized complete block design for two years of 2017- 2018 and 2018-2019 in Khorramabad city.Experimental treatments consisted of supplementary irrigation at four levels (including control, budding stage, flowering stage, and budding stage + flowering stage) as the main factor; foliar spraying with salicylic acid at three levels (including control, 0.5 mM, and 1 mM) as the first subfactor, and foliar spraying with humic acid at two levels (including control and 1 mM) as the second subfactor. In this study, different characteristics such as shoot nitrogen content, shoot phosphorus content, shoot potassium content, shoot copper content, shoot iron content, chlorophyll a, chlorophyll b, and chlorophyll total were evaluated. According to the results, various levels of supplementary irrigation and foliar spraying with humic acid and salicylic acid significantly affected the above characteristics. Mean comparison results revealed that the highest nitrogen content in the shoot (3.74%), shoot iron content (182.33 mg g-1), chlorophyll a (5.18 mg g-1 fresh weight), chlorophyll b (5.18 mg g-1 fresh weight) chlorophyll total (5.18 mg g-1 fresh weight) were recorded in the first year under treatment with supplementary irrigation at the budding stage and foliar spraying with salicylic acid (1 mM) and humic acid (1 mM).