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Morphology and Root Anatomy of Squash and Cucumber Seedlings Treated with Isopropyl N-(3-Chlorophenyl) Carbamate (CIPC)

1955; University of Chicago Press; Volume: 117; Issue: 1 Linguagem: Inglês

10.1086/335888

1940-1205

Marie A. Scott, Β. Esther Struckmeyer,

Polymer-Based Agricultural Enhancements

1. Squash and cucumber seeds were germinated in aqueous solutions of 1, 5, 10, or 15 p.p.m. of isopropyl N-(3-chlorophenyl) carbamate (CIPC) in order to study the anatomical effects of the herbicide. 2. Squash seedlings exhibited little response at a concentration of 1, 5, or 10 p.p.m. CIPC; at 15 p.p.m. secondary roots were shorter. Cucumber seedlings, however, showed inhibition of shoot growth and of both primary and secondary root growth at all concentrations of CIPC used. The response was greater at higher concentrations and with longer treatments. 3. The root anatomy of untreated cucumber seedlings was similar in general to that of untreated squash seedlings. However, Casparian bands of the squash endodermis were broad in transection and appeared 800-2150 μ from the root apex; those of cucumber were narrower and appeared 1740-5070 μ from the root apex. 4. Anatomically, the squash roots showed little effect at a concentration of 1, 5, or 10 p.p.m. CIPC. Treatment with 15 p.p.m. resulted in radial elongation of the pericyclic and endodermal cells in the mature region of the root. With longer treatments, no greater response was evident. 5. The region of elongation in the cucumber root showed an effect at a concentration of 1 p.p.m. CIPC; at 5 p.p.m. the region of maturation was affected. The pericyclic and endodermal cells in treated seedlings were radially elongated, and many of the cells in the meristematic region were hypertrophied. Some enlarged cells, each having either several nucleoli or one large nucleolus in a nucleus, were observed. Abnormal wall thickenings appeared on some cells, and tissues matured nearer the root apex. Increased response occurred in the mature region with longer treatment. 6. The most important effects of CIPC are the apparent inhibition of mitosis, the enlargement of cells, and the maturation of tissues near the root apex. The broader Casparian bands, their appearance closer to the root tip, and the upward extension of the rootcap in squash (as compared with cucumber) might retard the penetration of CIPC into the root tissues.