|Davis, Karen - NC AGR AND TECH STATE UNI|
|Niedziela, Carl - NC AGR AND TECH STATE UNI|
|Reddy, M - NC AGR AND TECH STATE UNI|
|Whipker, Brian - NORTH CAROLINA STATE UNIV|
Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 2009
Publication Date: March 2, 2011
Repository URL: http://hdl.handle.net/10113/50089
Citation: Davis, K., Niedziela, C.E., Reddy, M.R., Whipker, B.E., Frantz, J. 2011. Nutrient disorder symptomology and foliar concentrations of Clerodendrum thomsoniae. Journal of Plant Nutrition. 34:1079-1086. Interpretive Summary: Clerodendrum has been grown by the US floriculture industry for years, but there is limited information on how to fertilize this crop properly. Additionally, there are no photography-based diagnostic keys for symptoms of nutrient deficiencies for this species. Therefore, the goal of this research was to 1) determine the growth response of clerodendrum to a range of fertilizer supplies, 2) characterize the visual symptoms when clerodendrum began to express symptoms of nutrient deficiencies, and 3) establish nutrient concentration standards for leaves upon nutrient deficiency symptom expression. In Experiment 1, a green-leaf type of clerodendrum was grown for 129 days with complete fertilizer concentrations at five different rates. Above-ground shoot length and dry weight increased with fertilizer concentration. As expected, most nutrients increased with more fertilizer, but magnesium and sulfur decreased. Leaves were lighter green with low fertilizer supply; thus 200 mg.L-1 nitrogen is the recommended fertilizer supply rate because it provided adequate fertility without excessive growth. In Experiment 2, deficiencies of 11 essential elements and toxicity of boron were induced in a Clerodendron type with variegated-leaves. Plants were photographed and harvested for nutrient analysis when initial deficiency and toxicity symptoms were expressed. Nutrient deficiency symptoms were described and critical minimum leaf nutrient standards were established. The results from this study will help growers produce clerodendrum more effectively by minimizing stress caused by improper fertilization.
Technical Abstract: Clerodendrum (Clerodendrum thomsoniae Balf.) has been grown commercially for years, but limited information on mineral nutrition of it appears in the literature. Therefore, we sought to determine the growth response of clerodendrum to a range of fertilizer concentrations and to characterize the visual symptoms and establish foliar nutrient concentration standards of nutrient deficiencies from incipient to advanced stages of development. In Experiment 1, a green-leaf selection of clerodendrum was grown for 129 days with complete fertilizer concentrations based on nitrogen concentrations of 50, 100, 200, 300, and 400 mg.L-1. Shoot length and dry weight increased linearly with fertilizer concentration. Nitrogen, phosphorus, potassium, copper, iron, and manganese levels increased with fertilizer concentration, while magnesium and sulfur decreased. Although clerodendrum grown with 100 to 400 mg.L-1 nitrogen had similar foliar nitrogen, phosphorus, and potassium concentrations at 97 days, foliage was lighter green with '100 mg.L-1 nitrogen, thus 200 mg.L-1 nitrogen is recommended because it provided adequate fertility without excessive growth. In Experiment 2, deficiencies of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, and boron and boron toxicity were induced in a variegated-leaf selection grown in a hydroponic system utilizing silica sand as the substrate. Plants were harvested for nutrient analysis when initial symptoms were expressed. Nutrient deficiency symptoms were described and critical minimum foliar nutrient standards established. The results from this study have laid the groundwork for understanding the fertilization requirements of clerodendrum.