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Plant function and evolutionary biology
RESEARCH ARTICLE

Responses of pea plants to elevated UV-B radiation at varying nutrient levels: N-metabolism, carbohydrate pool, total phenolics and yield

Suruchi Singh A , Shashi B. Agrawal A and Madhoolika Agrawal A B
+ Author Affiliations
- Author Affiliations

A Laboratory of Air Pollution and Global Climate Change, Department of Botany, Banaras Hindu University, Varanasi-221005, India.

B Corresponding author. Email: madhoo.agrawal@gmail.com

Functional Plant Biology 42(11) 1045-1056 https://doi.org/10.1071/FP15003
Submitted: 8 January 2015  Accepted: 17 August 2015   Published: 29 September 2015

Abstract

The effects of elevated UV-B (280–315 nm) were assessed on nitrogen metabolism, carbohydrate pool, total phenolics, photosynthetic pigments, UV-B absorbing compounds, variables related to oxidative stress, biomass and yield of pea plants grown under various levels of NPK. The NPK levels assayed were: background NPK level (F0); recommended NPK (F1) and recommended NK + 1.5 × recommended P (F2) and the UV-B levels were: control (C) and elevated (T). The responses of T plants varied with different combinations of NPK. Yield reduced under elevated UV-B at all NPK levels with maximum reduction in F0T and minimum reduction in F1T. Leghaemoglobin content was reduced under elevated UV-B at all NPK levels. Maximum increase in malondialdehyde content recorded in F0T plants corresponded with higher superoxide and hydrogen peroxide contents. Nitrite reductase activity decreased significantly under UV-B at all NPK levels, but nitrate reductase activity increased significantly in F1T and F2T. Maximum reduction in C : N ratio of leaves in F2T plants suggests competition between sucrose synthesis and nitrate reduction under additional P level. The study concludes that application of recommended level of NPK caused least changes in N metabolism leading to minimum yield losses due to elevated UV-B stress.

Additional keywords: carbohydrate, nitrogen metabolism, NPK, pea, UV-B.


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