Protective effects of humic acid against chromium stress in wheat (Triticum aestivum L. cv. Delabrad-2)

Year 2019, Volume: 14 Issue: 2, 50 - 58, 30.06.2019

Adnan Akçin , Tülay Aytaş Akçin

Abstract

Wheat (T.
aestivum) is the world’s most widely cereal crop and is a staple food for a
over 50 % world’s population. Soils contaminated with heavy metals may cause
deleterious effects on human health. However, humic substances (humic acid and
fulvic acid) might benefit plant growth by improving nutrient uptake and the
activation of biomass production. Hence, the objective of the current study was
to investigate the effects of humic acid (HA) on photosynthetic pigment and
malondialdehyde content (MDA) against chromium stress in Triticum aestivum L. cv. Delabrad-2. For this purpose, four Cr
treatments (0.10, 0.20, 0.30, 0.50 mM) were applied to wheat seedlings and the
liquid humic acid sprayed on the leaves at 1.5 mg L^-1 dose alone or
in combination with chromium stress for 21 days. According to our results, the
higher concentration of Cr was found in the leaves in comparison with roots and
stems of wheat plants. The treatment with 0.6 mM Cr concentration was the most
effective for wheat. Total carotenoid, total chlorophyll, chlorophyll a and b
contents decreased in groups only chromium compared to HA+Cr groups depending
on the increased chromium dose. However, the application of
HA increased the chlorophyll a/b ratio and MDA content in plants as compared
with Cr treatment alone. We conclude that HA application eliminated the
toxicity of Cr stress by modulating the photosynthetic activities in wheat.

Keywords

Wheat, Heavy metal stress, Humic acid, photosynthetic pigment

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