Resumen

RIVERO-MALDONADO, G et al. Histological alterations caused by Brevipalpus phoenicis (Geijskes) to peduncles and sepals of Psidium guajava L.. Rev. Fac. Agron. [online]. 2008, vol.25, n.3, pp.525-549. ISSN 0378-7818.

Histological alterations caused to sepals and peduncles of small, medium and large size fruits of Psidium guajava L. by Brevipalpus phoenicis are described and quantified. From 30/10/2003 to 22/01/2004 samples of healthy, moderately and severely damaged fruits were collected from plants located at Centro Frutícola del Zulia, Mara County (19º83'53''N and 19º65'09''E), Venezuela. Transversal sections of tissues were micro photographed and digitalized by using Pro Plus^® software Image program, with the purpose of establishing comparisons through quantification made by using Tool^® software Image program. The variables evaluated were: epidermal thickness or necrosed superficial layer (NSL), parenchyma thickness, and number of phenolic cells (NPC), number of sclereids (NS) and thickness of cell wall. The statistical procedures analysis of variance, test of means comparison (Tukey and DMS) and frequency analysis. The results showed that the epidermal and parenchyma tissues of sepals and peduncles with flat mite damage were modified into a necrosed superficial layer, whose thickness increased according to the combination of the studied factors. The NPC in small fruits with healthy peduncles and moderately damaged sepals ranged from 0.35 to 24 cells.12399 µm^-2. The NS ranged from 0 to 3 sclereids.12399 µm^-2, not being as abundant in sepals or peduncles, as observed in mesocarp. Considering that the epidermal and parenchymatic layers have meristematic capacity, the alterations caused by the mite could affect the cellular regeneration which is important and necessary to the fruit growing, as well as to the wounds healing in the analyzed structures.

Palabras clave : Histopathology; guava; flat mite.