Anatomy of some Species in Family Cucurbitaceae from Nigeria

Abstract

Nine genera comprising ten species of the family Cucurbitaceae were investigated using foliar anatomy to identify additional diagnostic characters of taxonomic importance. Both qualitative and quantitative data were collected, while quantitative data were analyzed using Duncan's Multiple Range Test to determine significant differences among taxa. The results revealed both similarities and differences in foliar anatomical characters. Shared features confirm the close relationship of the species within the family, whereas variations support their taxon-specific delimitation. All species exhibited actinodromous venation, polygonal to rectangular areoles, single, bifurcated or forked veinlet endings, anomocytic and brachyparacytic stomata, and glandular and non-glandular trichomes. However, the species were distinguished by epidermal cell shape, anticlinal wall pattern, stomatal type combinations, stomatal distribution, stomatal size, stomatal index, and trichome type. Irregular epidermal cells on both leaf surfaces were diagnostic for Telfairia occidentalis and Trichosanthes cucumerina. Telfairia occidentalis was uniquely hypostomatic, whereas all other species were amphistomatic. This hypostomatic condition may enhance water-use efficiency and resilience to climate-related stress through its influence on transpiration and gas exchange. Anomocytic and brachyparacytic stomata predominated, anisocytic stomata occurred occasionally, while tetracytic stomata were unique to Cucumeropsis mannii. Stomatal size also provided useful taxonomic evidence, being smallest in Cucurbita maxima and largest in Trichosanthes cucumerina on both leaf surfaces. Overall, species of Cucurbitaceae belonged to the lower (5–15%) and moderate (15–25%) stomatal index categories. The functional significance of stomatal index in relation to stomatal efficiency is also discussed. These findings demonstrate that foliar anatomical characters provide valuable evidence for species delimitation and taxonomic classification within the Cucurbitaceae.