| Abstract: | Abstract Sanilac and Saginaw varieties of navy beans were grown on Wisner silty clay loam. Treatments of no added Zn and 3 ppm Zn were applied to the soil fertilized with N, K, and 500 ppm P. Selected plant tissues were harvested two, four, six, or eight weeks after planting. The weights and Zn contents of some tissues were not affected by Zn application regardless of variety but the growth of the plant parts above the primary leaves and the Zn contents of the trifoliolate leaves increased with Zn rate. The three oldest trifoliolate leaves and younger tissues showed equal or greater increases in growth and Zn contents than the total plant tops, but the primary leaves and the lower portions of stems were less influenced by available Zn in the soil. These responses indicated that the three oldest trifoliolate leaves were the most reliable indexes for available Zn throughout the growing period. As the plants matured, the growth and Zn contents of the young tissues of the Saginaw variety responded more to Zn fertilization than did the young tissues of Sanilac. This differential response appeared to be partially due to the lower plant weights of the Saginaw than the Sanilac variety where no Zn had been applied to the soil. |
