Effects of zone, drought and copper stresses and their interactions on some biochemical traits and grain yield of Fumaria parviflora Lam.

Introduction Copper (Cu2+) is an essential element for the plant's metabolic processes, which is required by the plant  for many enzymatic activities and playing a vital role in various physiological processes, growth, and development in small amounts. On the other hand, high concentrations of copper can be toxic to plants and high accumulation of this element in the soil prevents the elements needed for growth from reaching the aerial organs and prevents the normal growth of the plant. Drought stress also disrupts the growth and water relations in the plant and leads to a decrease in the efficiency of water consumption in the plant and causes a variety of physiological responses along with yield reduction. Soil contamination with heavy metals adversely affects plants growth, its development and metabolism in many parts of the world including arid and semi-arid regions. Multiple stresses caused a wide range of changes in plant physiology and metabolisms in plants. Fumaria parviflora Lam (Fumariaaceae) is an annual herbaceous medicinal plant with branched stems that is cultivated in arid and semi-arid regions of Iran. Materials and methods This study was conducted as a factorial experiment based in a completely randomized design in greenhouse conditions with three replications. In this study, the independent and combined effects of different concentrations of copper element (control, 50, 150, 300 and 400 mg kg-1) and different levels of drought stress (control, 50% and 75% based on soil moisture percentage discharge) was investigated on seed yield, malondialdehyde, soluble carbohydrates, proline, total anthocyanin content, total phenolics content, total flavonoids content, and antioxidant activity of Fumaria Parviflora Lam. The seeds of the plant were collected from two mining areas (Askari ravar and Rabor) from four zones (Z1, Z2, Z3 and Z4) in Kerman province. Results and discussion The results of this study showed that the lowest amount of total phenoolics (89.3 mg GAE g-1 DW) and total flavonoids (8.1 mg QE g-1 DW) content was observed in the control treatment and the highest amounts for total phenolics (123.2 mg GAE g-1 DW) and total flavonoids (14.7 mgQE g-1 DW) were observed in severe drought stress. Here, the independent and combined effects of different concentrations of copper element and drought stress showed an  increasing effect the biochemichal traits. The interaction effect of 50 mg kg-1 of copper on drought stress was decreasing in grain yield, proline and anthocyanin content. At a concentration of 150 mg kg-1, the copper element had an increasing effect on the drought stress for proline content, amount of soluble carbohydrates and anthocyanin content. The interaction effects of copper and drought stress showed that in concentrations of 300 and 400 mg kg-1, copper has an increasing effect in the presence of drought stress for proline, anthocyanin, total phenolics, total flavonoids, antioxidant activity and malondialdehyde content, but had a reducing effect on soluble carbohydrates. Conclusion This  study  was  studied   by the  first time  on the  combined effects  of a heavy  metal  and  drought stress on F. parviflora. Under moderate drought stress, F. parviflora Lam. was able to withstand the stress up to the concentration of 150 mg kg-1 of copper by using defense mechanisms. Also, the areas with high concentration of copper (Z3 and Z4) in the studied mining areas were more tolerant to high copper stress and showed higher grain yield than the areas with lower concentration of copper (Z1 and Z2). The findings confirmed the use of F. parviflora as a suitable species for soils contaminated with low to moderate copper (50-150 mg kg-1) under moderate drought stress. Based on these findings, it can be concluded that F. parviflora can deal with copper stress due to its active antioxidant defense system. It is possible to collect the seeds of this plant from areas with high concentration of copper (300 and 400 mg kg-1) for the cultivation of F. parviflora under contaminated areas with copper stress.