Anatomia Foliar Quantitativa do Capim Marandu Sob Influência do Nitrogênio

Abstract

Aimed to analyze the anatomy’s leaf of Marandu grass (Brachiaria brizantha cv. Marandu.) submitted to N rates (0, 25, 50, 75 and 100 kg ha-1). These characteristics were analyzed: thickness of the leaf blade (TLF), thickness of adaxial epidermis (TAE), thickness of the abaxial epidermis (TAE), distance between vascular bundles (DVB), diameter of the phloem (DPL), diameter of xylem (DXL ), thickness of mesophyll (TME), percentage of bulliform cells (CBU%), percentage of the bundle sheath (BFV%) and percentage of sclerenchyma (SCL%). The data were subjected to analysis of variance by F test, and when were significant (p≤0,05), the models appropriate to the nature of the response regression were applied. The TLF had positive linear response (p<0.01) with increasing dose of N. TAE showed a negative linear response (p<0.05) and the reverse was observed for the TAE (p<0.01). The DVB was unchanged with doses of N (p>0.05), but the DPL and the DXL had similar responses, with the positive linear increase (p<0.05). TME and CBU% had a increased linearly (p <0.05). The BFV% was not altered (p> 0.05) with increasing N and the SCL% showed a negative linear response. The Nitrogen fertilization causes changes in leaf’s anatomy of Marandu grass (Brachiaria brizantha cv. Marandu), which seems to be an adaptation to the condition of most substrate availability for growth.