WHEAT SEED QUALITY IN RESPONSE TO MOLYBDENUM AND PHOSPHORUS

ABSTRACT

Similarity of the molybdate and phosphate anions suggests that these nutrients are likely to interact in plant metabolism. This relationship has not been explained with respect to seed quality. The objective of this study was to examine wheat (Triticum aestivum L.) seed quality in response to varying nutrient solution concentrations of molybdenum (Mo) and phosphorus (P). Seeds of wheat, cultivar Tugela DN, were produced in pots under controlled environmental conditions. Plants were watered twice a week with a modified Hoagland's nutrient solution containing no Mo and 10 mg L⁻¹ P, supplied from a separate source, as a control. Separate Mo (1.8, 3.6, and 5.4 mg L⁻¹) and P (10, 20, and 30 mg L⁻¹) treatments were also applied simultaneously as the Hoagland's solution to plants from one week after pre-germination in a growth chamber to seed maturity. Seed yield, germination, α-amylase activity and total protein concentration were determined in seeds harvested at a moisture content of about 12%. Results showed that P did not affect Mo suppression of α-amylase activity, but there was a negative interaction between Mo and P with respect to seed germination. Both Mo and P increased seed protein content, seed yield and seedling vigor. These data suggest that while P fertilization contradicts the induction of seed dormancy by Mo, this interaction does not negate the reduction of late maturity α-amylase activity by Mo. Since late maturity α-amylase reduction is the major goal of pre-harvest sprouting alleviation, these data could be useful in providing an agronomic tool to alleviate pre-harvest sprouting while simultaneously enhancing wheat seed vigor.

ACKNOWLEDGMENTS

The author thanks The Small Grain Centre, Bethlehem, South Africa for donating seed.