Photosynthesis light-independent reactions are sensitive biomarkers to monitor lead phytotoxicity in a Pb-tolerant Pisum sativum cultivar

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Maria da Conceição Santos (Author) FCUP; et al (Author) Other

Journal

Title: Environmental Science and Pollution Research

Vol. 22 No. 9

Pages: 574-585

ISSN: 0944-1344

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 44 Citations

Scopus - 49 Citations

Other information

Authenticus ID: P-00A-4S2

DOI: 10.1007/s11356-014-3375-9

Abstract (EN): Lead (Pb) environmental contamination remains prevalent. Pisum sativum L. plants have been used in ecotoxicological studies, but some cultivars showed to tolerate and accumulate some levels of Pb, opening new perspectives to their use in phytoremediation approaches. However, the putative use of pea plants in phytoremediation requires reliable toxicity endpoints. Here, we evaluated the sensitivity of a large number of photosynthesis-related biomarkers in Pb-exposed pea plants. Plants (cv. "Come de Belier") were exposed to Pb concentrations up to 1,000 mg kg(-1) soil during 28 days. The photosynthetic potential biomarkers that were analyzed included pigments, chlorophyll (Chl) a fluorescence, gas exchange, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activity, and carbohydrates. Flow cytometry (FCM) was also used to assess the morpho-functional status of chloroplasts. Finally, Pb-induced nutrient disorders were also evaluated. Net CO2 assimilation rate (A) and RuBisCO activity decreased strongly in Pb-exposed plants. Plant dry mass (DM) accumulation, however, was only reduced in the higher Pb concentrations tested (500 and 1,000 mg kg(-1) soil). Pigment contents increased solely in plants exposed to the largest Pb concentration, and in addition, the parameters related to the light-dependent reactions of photosynthesis, F-v/F-m and Phi(PSII), were not affected by Pb exposure. In contrast to this, carbohydrates showed an overall tendency to increase in Pb-exposed plants. The morphological status of chloroplasts was affected by Pb exposure, with a general trend of volume decrease and granularity increase. These results point the endpoints related to the light-independent reactions of photosynthesis as more sensitive predictors of Pb-toxicity than the light-dependent reactions ones. Among the endpoints related to the light-independent photosynthesis reactions, RuBisCO activity and A were found to be the most sensitive. We discuss here the advantages of using these parameters as biomarkers for Pb toxicity in plants. Finally, we report that, despite showing physiological disorders, these cultivar plants survived and accumulated high doses of Pb, and their use in environmental/ decontamination studies is open to debate.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12