Seed Pretreatment and Foliar Application of Proline Regulate Morphological, Physio-Biochemical Processes and Activity of Antioxidant Enzymes in Plants of Two Cultivars of Quinoa (Chenopodium quinoa Willd.).

Hira Yaqoob,Leonard Wijaya,Noman Khalid,Parvaiz Ahmad,Muhammad Sadiq,Muhammad Ashraf,Mohammed Nasser Alyemeni,Nudrat A Akram,Samrah Iftikhar

doi:10.3390/plants8120588

Abstract

In the current study, the effects of exogenously applied proline (25 and 50 mM) and low-temperature treatment were examined on the physiochemical parameters in the plants of two cultivars (V1 and V2) of quinoa (Chenopodium quinoa Willd.). The seeds were also exposed to chilling stress at 4 °C before sowing. Plants raised from the seeds treated with low temperature showed reduced plant growth and contents of chlorophyll and carotenoids, but they had significantly increased contents of malondialdehyde, proline, ascorbic acid, total free amino acids, total soluble sugars, and total phenolics, as well as the activity of the peroxidase (POD) enzyme. Cold stress applied to seeds remained almost ineffective in terms of bringing about changes in plant root, hydrogen peroxide, glycine betaine and activities of superoxide dismutase (SOD), and catalase (CAT) enzymes. The exogenous application of proline significantly increased plant growth, the contents of chlorophyll, carotenoids, proline, ascorbic acid, total free amino acids, phenolics, and total soluble sugars, as well as the activities of SOD, POD, and CAT, but it decreased malondialdehyde content. Overall, foliar application of proline was better than the seed treatment in improving root dry weight, root length, chlorophyll a, carotenoids, glycine betaine, ascorbic acid and superoxide dismutase activity, whereas seed pre-treatment with proline was effective in improving shoot dry weight, shoot length, hydrogen peroxide, malondialdehyde, and peroxidase activity in both quinoa cultivars.

Highlights

IntroductionHeat, drought, salinity, toxicity of heavy metals, etc. that severely influence plant growth and development, thereby decreasing overall plant yield
Abiotic factors include cold, heat, drought, salinity, toxicity of heavy metals, etc. that severely influence plant growth and development, thereby decreasing overall plant yield
Data showed that the shoot fresh and dry weights of the plants of both quinoa cultivars raised from cold-stressed seeds were significantly (P ≤ 0.001) reduced as compared to those of the plants raised from non-treated seeds

Summary

Introduction

Heat, drought, salinity, toxicity of heavy metals, etc. that severely influence plant growth and development, thereby decreasing overall plant yield. That severely influence plant growth and development, thereby decreasing overall plant yield. They act as growth-limiting factors by producing reactive oxygen species (ROS), causing oxidative stress [1,2,3]. This oxidative stress triggers metabolic disorders and causes a loss of organelle functions and cell injury, thereby leading to cell death [4,5]. Cold stress is one of the major abiotic stresses that directly influences as well as reduces plant growth and yield [6,7,8]. In response to chilling stress, a number of defensive processes activate within the cells such as cell structure modification, accumulation of antioxidants and osmoprotectants, modification in gene expression, and the generation of anti-freezing proteins [12,13]

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Results

Discussion

Conclusion