Physiological dynamics as indicators of plant response to manganese binary effect

Area of Science:

• Environmental Science
• Plant Physiology
• Bioremediation

Background:

• Heavy metals, including manganese (Mn), pose significant risks to plant physiology.
• Plants possess inherent physiological mechanisms to mitigate heavy metal toxicity.
• Broussonetia papyrifera shows promise for phytoremediation of Mn-contaminated soils.

Purpose of the Study:

• To investigate the dynamic physiological responses of Broussonetia papyrifera to varying manganese (Mn) stress levels.
• To assess the phytoremediation potential of B. papyrifera by analyzing Mn uptake and translocation.
• To understand the impact of Mn concentration and stress duration on key physiological indicators.

Main Methods:

• Pot experiments were conducted using B. papyrifera exposed to six different Mn concentrations (0–5 mmol/L) for 60 days.
• Measurements included chlorophyll content, malondialdehyde (MDA), proline (PRO), soluble sugar, and antioxidant enzyme activities (SOD, CAT, POD).
• Manganese absorption, translocation (BCF, TF), and root structure were analyzed.

Main Results:

• Bioconcentration factor (BCF) and translocation factor (TF) for Mn increased with Mn concentration, with TF exceeding 1 at higher levels (>100 mmol/L).
• Manganese distribution followed the order: leaf > stem > root.
• Low Mn concentration (1 mmol/L) promoted root development, while Mn concentration and stress duration significantly affected most physiological indexes.

Conclusions:

• Broussonetia papyrifera exhibits dynamic physiological adaptations to manganese stress.
• The study highlights the importance of considering Mn concentration when selecting plant tissues for monitoring phytoremediation effectiveness.
• B. papyrifera demonstrates significant potential for the phytoremediation of manganese-contaminated soils.