Growth and Nutrient Accumulation and Distribution in Grain Sorghum. II. Zn, Cu, Fe, and Mn Uptake and Distribution1
- G. L. Jacques,
- R. L. Vanderlip and
- Roscoe Ellis2
Recognized, micronutrient-deficiency symptoms in grain sorghum [Sorghum bicolor (L.) Moench] emphasize the need for micronutrient research in the crop. To conduct fertility trials and interpret plant tissue nutrient analyses, it is essential to understand nutrient uptake and distribution patterns. We investigated Zn, Cu, Fe, and Mn behavior in grain sorghum throughout its growth cycle. Two grain sorghum hybrids (‘RS 610’ and ‘RS 702’) were planted at the Kansas State University Agronomy Farm, Manhattan, in 1970 and 1971. Weekly samples of plant parts were analyzed for Zn, Cu, Fe, and Mn.
Nutrient concentrations in blade, sheath, culm, and head tissues generally decreased until maximum weight was reached and then stabilized or decreased only slightly and gradually as grain developed. Manganese in blade tissue, an exception, increased throughout the two hybrids' growth.
Whole plant nutrient concentrations decreased through most of plant growth. Zinc and Cu concentrations did not decrease so much during grain development as during vegetative growth.
Head tissue usually was lowest in nutrient concentration of all plant parts. Nutrient contents varied in other parts, but culm tissue was generally highest early in the sorghum's growth.
Hybrid RS 702 generally had a larger proportion of its nutrients in the vegetative portion than did RS 610. Differences occurred among plant parts in nutrient distribution, and uptake was not always proportional to dry matter accumulation.
Copper and Zn were translocated from vegetative plant parts to the head as grain developed, but Mn was not.
Nutrient uptake generally had reached 50% or more of total uptake in the plants when they completed vegetative growth. Nutrient uptake preceded dry matter accumulation. Differences between years and hybrids in total nutrient uptake occurred, but uptake curves were similar with definite, generalized patterns.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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