Impact of 11 Elemental Nutrient Deficiencies on Shoot and Root Growth, and Foliar Analysis Standards of 13 Ornamental Taxa with Emphasis on Ca and B Control of Root Apical Meristem Development

Abstract

Tissue analysis standards and complete visual deficiency symptoms of N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, and B are crucial for monitoring plant nutrient status. Limited information is available on visual disorder symptoms and foliar analysis standards for vinca, celosia, marigold, zinnia, salvia, pansy, impatiens, begonia, petunia, ornamental cabbage, snapdragon and New Guinea impatiens. Synoptic visual deficiency symptoms were as follows: N - Symptoms began on lower leaves as uniform light green chlorosis to yellow and finally necrotic. Development of red to purple pigmentation was observed in marigold, snapdragon, begonia and ornamental cabbage. P - All foliage became deeper green, then lower leaves became purplish/reddish in some species, and finally necrotic. K - In the early stage of deficiency, plants became compact and deeper green. Later, necrosis developed on tips and margins of older leaves. Ca - Necrotic symptoms first developed on roots, then on young leaves and shoot apex. However, the shoot apices of New Guinea impatiens and impatiens did not develop necrosis. Mg - Interveinal chlorosis developed on older leaves followed by necrosis along the margins. S - The entire leaves became uniformly lighter green. Then the margins of all leaves became more chlorotic then the remainder of the leaves. Eventually, the margins developed necrosis. Fe - Young leaves developed interveinal chlorosis, generally from the base. Then the entire lamina turned chlorotic. The chlorosis then gave way to bleached whitish-yellow. Mn - Young and recently matured leaves developed chlorosis, and mature leaves developed stippling of necrosis. Drastic reduction of shoot and root growth was common. Flowering was severely inhibited. Cu - Impaired flower development includes reduced size and premature abscission. Desiccation and sudden death of tissue occurred on recently mature leaves. Chlorosis was generally not a distinguishing feature. Zn - Young and recently matured leaves developed puckering, chlorosis, and necrosis. Some plants developed purple pigmentation. B - Foliage became darker green and glossy. Young and recently matured leaves became thick, leathery and brittle with severe distortions. The roots were short and stubby. The rate at which symptoms occurred is an indication of the species sensitivity to a particular nutrient deficiency. The nutrient deficiency symptoms that were first to occur by species were as follows: begonia - N and Fe, celosia - N and K, impatiens - Ca, marigold - N and Fe, New Guinea impatiens 'Grenada' - Ca, New Guinea impatiens 'Timor' - Fe, ornamental cabbage - Ca and Fe, pansy - Fe, petunia - Fe, salvia - N, snapdragon - Ca, vinca - Fe, and zinnia - Ca. Root and shoot apical meristems are specialized areas where cell proliferation and organogenesis take place. The absence of Ca, B and CaB greatly reduced primary root growth relative to control within 12 hours. The number of abnormal nuclei decreased in the order of Ca > CaB > B deficient treatments. Nuclei in both Ca and CaB deficiency treatments showed a significant decrease in volume. Boron deficiencies initially resulted in an increased mitotic index (MI), concurrent with root apical meristem (RAM) distortion. Most of the increase in root diameter could be explained by an increase in the number of cell files in the cortex. Ca and B deficiencies together reduced both the MI and root tip distortion. Lack of B arrests cell death, and lack of Ca arrests cell division. The absence of B triggered cell division in the peripheral lateral root cap. This indicates that B may help to mitigate Ca deprivation effects in Ca deficient environment.

Description

Keywords

disorders, Vinca, B, Zn, New Guinea impatiens, Begonia, symptoms, Zinnia, Celosia, deficiency, ornamental, bedding plant, chromatin, Mg, nuclei, mitotic index, nutrient, deprivation, foliar analysis, foliar standards, hydroponic, Marigold, S, Ca, K, Snapdragon, Ornamental cabbage, Petunia, cell analysis, N, P, Cu, Mn, Fe, Pansy, chlorosis, necrosis, Salvia, Impatiens

Citation

Degree

PhD

Discipline

Horticultural Science

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