Detrimental Effects of Lead Phytotoxicity on Growth, Yield, and Metabolism of Rice

Abstract

To elucidate the deleterious effects of excessive lead (Pb) on rice (Oryza sativa) cv. Swarn Mansoori, plants were grown in refined sand in complete nutrient solution for 42 days. On the 43rd day, Pb nitrate was superimposed at 1 mM (to rice) for 104 days (till harvest). A set of plants in complete nutrient solution was maintained as control for the same period. Excess Pb reduced the dry weight pronouncedly at harvest (after 104 days of metal supply) when the grain yield also decreased. Lead accumulation reduced the concentrations of chlorophyll in leaves, carotene, sugars, phenols, nonprotein nitrogen, protein, iron, manganese, copper, zinc, Hill reaction activity, and peroxidase activity (one of the anti-oxidative enzymes), but increased the concentrations of sulphur, phosphorus, magnesium (early stage) protein nitrogen, and activity of catalase, ORDER REPRINTS acid phosphatase, and ribonuclease in leaves of rice. Except for slight growth depression and reduction in number and size of leaves, tillers and inflorescence, no other visible symptoms of excessive Pb could be seen before harvesting.

Lead Phytotoxicity Induced Changes in Biochemical Markers in Germination and Seedlings in Durum Wheat <i>Triticum durum</i> Desf. Cv.Vitron and Gta

“…Gta and Vitron. These results are similar to other works cited in the literature and found by Chatterjee et al (2004) who observed the same effect of high lead levels on rice seeds. Accordingly, the work of Seregin and Ivanov (2001) on Phaseolus vulgaris and Pisum sativum seeds has proved that these species are now considered to be susceptible to heavy metals, which do not germinate even in very low concentrations.…”

“…The action of lead on the protein content shows that high concentrations can reduce protein content. Their synthesis is slowed or even inhibited (Chen et al, 2002;Chatterjee et al, 2004). This reduction appears as a result of the consequences of the action of lead, such as decreased or stimulated protease activity and/or decreased free amino acid content (Xiong et al, 2006).…”

Nitric Oxide Increases Pb Tolerance by Lowering Pb Uptake and Translocation as well as Phytohormonal Changes in Cowpea (Vigna unguiculata (L.) Walp.)

“…According to our observations in the present study, lead toxicity reduced promoting phytohormone (IAA, cytokinin and GA 3 ) level, raised ABA content, increased lead uptake and translocation, decreased stomatal conductance and leaf area of cowpea plants resulted in reduced seed yield. Reducing crop yield under Pb stress has been reported by other researchers (Balba et al 1991;Chatterjee et al 2004;Hussain et al 2006). Similarly, Jhanji et al (2012) and Kumari et al (2010) found that in chickpea and Brassica napus Cd toxicity adversely affected seed yield but exogenous NO improved this trait.…”

Lead Uptake, Toxicity, and Detoxification in Plants

“…Results from multiple studies demonstrate that nutrient uptake by plants is significantly affected by the presence of lead (Chatterjee et al 2004;Sharma and Dubey 2005;Gopal and Rizvi 2008). Although data are insufficient to allow a definitive conclusion to be drawn, it is known that lead affects plant mineral uptake.…”

“…The effect of lead on the total concentration of protein is unclear, although high concentrations may decrease the protein pool (Chatterjee et al 2004;M i s h r a et al 2006; Garcia et al 2006;Piotrowska et al 2009). This quantitative decrease in total protein content is the result of several lead effects: acute oxidative stress of reactive oxygen species (ROS) (Piotrowska et al 2009;Gupta et al 2009), modification in gene expression (Kovalchuk et al 2005), increased ribonuclease activity (Gopal and Rizvi 2008), protein utilization by plants for the purposes of lead detoxification (Gupta et al 2009), and diminution of free amino acid content (Gupta et al 2009) that is correlated with a disturbance in nitrogen metabolism (Chatterjee et al 2004). However, certain amino acids, like proline, increase under lead stress (Qureshi et al 2007).…”