Non-structural carbohydrates in maize with different nitrogen tolerance are affected by nitrogen addition

Area of Science:

• Plant Physiology
• Agricultural Science
• Biochemistry

Background:

• Non-structural carbohydrates (NSCs) are vital for plant growth and adaptation.
• Nitrogen (N) application influences NSC levels, but effects on maize cultivars with varying N tolerance are not fully understood.
• Previous research focused mainly on leaf and stem NSC responses, neglecting whole-plant dynamics and translocation.

Purpose of the Study:

• To investigate the impact of different nitrogen levels on NSC accumulation and translocation in maize.
• To compare NSC responses between N-efficient (ZH311) and N-inefficient (XY508) maize cultivars.
• To elucidate the physiological mechanisms underlying N tolerance in maize.

Main Methods:

• Field pot and hydroponic experiments were conducted with varying N concentrations.
• Two maize cultivars, ZH311 (N-efficient) and XY508 (N-inefficient), were used.
• Analysis of NSC content, starch, and soluble sugars in vegetative organs and ears was performed.

Main Results:

• Low-N stress increased NSC accumulation in vegetative organs and enhanced NSC translocation in stems, mitigating yield loss.
• N application significantly affected starch content in ZH311's vegetative organs but had less impact on soluble sugars and whole-plant NSC.
• ZH311 demonstrated a greater capacity to convert starch into soluble sugars under low N conditions compared to XY508, preserving yield and starch quantity.

Conclusions:

• Maize utilizes NSC accumulation and translocation to adapt to low-N stress and minimize yield reduction.
• Cultivar-specific differences in NSC metabolism, particularly starch-to-soluble sugar conversion, are crucial for N tolerance in maize.
• The ability of ZH311 to efficiently manage NSC under low N highlights a key physiological mechanism for its superior N-use efficiency.