Effects of sand burial stress on maize (Zea mays L.) growth and physiological responses

We examined the effects of sand burial on the growth and the physiological response of maize (Zea mays cv. Zhengdan958) in the Horqin sandy lands. We had five treatments that varied in the amount of sand burial: control (no burial), A (burial to 1/4 of plant height), B (burial to 1/2 of plant height), C (burial to 3/4 of plant height), and D (burial to 100% of plant height). We then measured survival rate, plant height, above-and belowground biomass, yield, and activity of antioxidant enzymes: superoxide dismutase, peroxidase, catalase, and malondialdehyde content. Results show that the survival rate (91.67%) and plant height (230.3 cm) of maize under Treatment A at harvest time are significantly higher (P < 0.05) than those under other treatments; sand burial stress does not change the specific value of above and belowground biomass. Shallow burial (Treatment A) had no negative effects on the survival and growth of maize, but does decrease maize crop yield. Malondialdehyde content in shallow sand burial treatments (Treatments A and B) remained at low levels, but under sand burial ≥ 3/4 plant height (Treatments C and D) they increased significantly. Superoxide dismutase activity increased significantly 12 days after sand burial and the increase under Treatment A is the highest (203%). Under all treatments, peroxidase activity increased 6 days after sand burial, but decreased significantly 12 days after sand burial. Catalase activity under all burial treatments was lower than that in the control. Sand burial should be avoided in the seedling stage of maize in our study area because even shallow burial can decrease yield.