Morpho‐Physiological Growth and Yield Responses of Two Contrasting Maize Cultivars to Cadmium Exposure

Abstract

Increasing soil contamination by cadmium (Cd) has emerged one of the gravest threats to environmental sustainability and global food security. Maize, a major staple food, is supposed as the conspicuous source for intake of Cd by human beings. The present study investigated the morpho‐physiological growth and yield responses of two contrasting maize cultivars (Run Nong 35 and Wan Dan 13) to different Cd toxicity levels (0, 75, 150, 225, 300, and 375 μM). A considerable reduction in the growth and yield performance of both maize cultivars were noticed upon exposure to Cd stress and such a reduction governed by Cd was concentration dependent. Therefore, an increase in Cd concentration resulted in a proportional decrease in all growth (plant height, number of leaves per plant, leaf area, and ear length) and yield attributes (number of kernels per row, number of kernels per cob, and 100‐kernel weight). Osmolytes accumulation (soluble proteins, soluble sugar, and proline contents) also varied in the response to different Cd toxicity levels and maximum values for these attributes were recorded at 375 μM Cd in both cultivars. Furthermore, pronounced reduction in gas exchange attributes (photosynthesis, stomatal conductance, transpiration rate, and water use efficiency), relative water contents and chlorophyll contents were observed in Cd‐stressed plants. Cultivar variations were also apparent and Wan Dan 13 outperformed the Run Nong 35 for all studied attributes. Wan Dan 13 appeared a promising maize cultivar manifesting Cd tolerance that was related to higher osmolytes accumulation and better photosynthetic activity.

Morph‐physiological responses of two switchgrass (Panicum virgatum L.) cultivars to cadmium stress

“…the present study showed that Cd significantly decreased the chlorophyll contents of switchgrass, which is similar with the result of Anjum et al (2015).…”

“…The chlorophyll biosynthesis mechanism and the key enzymes involved in it could be impaired by excess Cd, which would hinder the synthesis of chlorophyll. On the other hand, Cd is suggested to destroy chlorophyll by replacing Mg in chlorophyll, which would lead to disintegration of chlorophyll (Shi et al 2012;Anjum et al 2015). The results in Table 2 Effects of cadmium (Cd) on the root length (RL), surface area (RA) and root volume (RV) of different root segments in 0-0.3, 0.3-0.6, 0.6-0.9 and >0.9 mm diameter classes for the two cultivars *P < 0.05, **P < 0.01, ***P < 0.001.…”

“…On the other hand, Cd is suggested to destroy chlorophyll by replacing Mg in chlorophyll, which would lead to disintegration of chlorophyll (Shi et al 2012;Anjum et al 2015). There are many possible reasons for Cd stress decreasing chlorophyll content.…”

Leaf gas exchange, source–sink relationship, and growth response of cotton to the interactive effects of nitrogen rate and planting density

“…Relative water contents (RWC) were measured from 20 days after emergence (DAE), to 120 DAE with an interval of 20 days, and then, average was taken to examine final RWC in cotton under studied treatments. For RWC measurement, first, leaf fresh weight (Wf) was measured; following this saturated weight of leaves (Ws) was measured after floating leaves in water for 18 h. Leaf dry weight (Wd) was measured (at 70°C) after drying the leaves in oven for 72 h (Anjum et al 2016). The RWC (%) were computed as…”

“…Relative water contents (RWC) explain turgidity of cells; however, reduction in turgidity results in reduced leaf water contents and declined water use efficiency (González and González-Vilar 2001). Studies reported that measurement RWC is a good indicator of plant growth and plant leaf gas exchange ability (Jensen et al 2000;Anjum et al 2016).…”