Alterações morfofisiológicas em folhas de Coffea arabica L. cv. "Oeiras" sob influência do sombreamento por Acacia mangium Willd / Morphophysiological alterations in leaves of Coffea arabica L. cv. 'Oeiras' shaded by Acacia mangium Willd

Diferenças na disponibilidade de radiação podem causar modificações na estrutura e função das folhas do cafeeiro, que podem responder de maneira diferencial à radiação por alterações morfológicas, anatômicas, de crescimento e na taxa fotossintética. O objetivo deste trabalho foi avaliar características morfofisiológicas de cafeeiros (Coffea arabica L. cv. "Oeiras") sombreados por acácia (Acacia mangium Willd.) na época seca e chuvosa no sul de Minas Gerais. As maiores taxas fotossintéticas e maiores espessuras da epiderme adaxial foram observadas na estação chuvosa nas linhas de cafeeiros a pleno sol. O sombreamento influenciou em menor espessura das folhas e em espaços intercelulares maiores no tecido esponjoso. Foi também verificada mudança na forma dos cloroplastos, os quais apresentaram-se mais alongados em folhas de cafeeiros a pleno sol quando relacionados aos arborizados.

Light availability is one of the most important environmental factors affecting leaf structure and functions in coffee plants that can respond differently to radiation by changes in leaf anatomy, morphology, growth and photosynthetic rate. The objective of this research was evaluate some morphophysiological aspects in leaves of coffee (Coffea arabica L. cv. 'Oeiras') cropped under shelter trees in the south of Minas Gerais during the rainy and dry season. The shade caused lower leaves thickness and higher intercellular spaces in spongious tissue. There was also verified a change in chloroplast shape, which showed more elongated in coffee tree kept at full sunlight in relation to that ones maintained on shading.

Identification of leaf structure of Cyclocarya paliurus / 中草药

Objective To study the leaf morphology and structure of Cyclocarya paliurus.Methods Foliar maceration,preparation of venation order,sectioning paraffin blocks,and scanning electron microscope were used to study the leaf morphology and structure.Results Cuticular papillates,glandular hairs,peltate scales,and non-glandular hairs presented on the leaf epidermis of C.paliurus.Anomocytic stomata were confined to the lower epidermis.Large cluster crystals existed in the uppermost layer of palisade cells.Midrib included one closed vascular system and one additional vascular strand.Secondary veins are semicraspedodromous and form marginal loops,tertiary veins are percurrent,quaternary veins form orthogonal or polygonal areoles filled up by branched and freely ended veinlets.Conclusion These structure characteristics are first reported and are useful for leaf identification of C.paliurus from other Juglandaceae plants.

Structural analysis and aloin determination in leaves of Aloe arborescens at different leaf age / 中草药

Object To explore the content of aloin in the leaves of Aloe arborescens Mill at different leaf age and its difference reason Methods The aloin content was determined by HPLC and anatomical structure of the leaves was studied with semi thin section Results The aloin content declines and the volume of large parenchymatous cell in vascular bundle atrophies from top to bottom with leaf growth in the same plant Conclusion The above results may provide references of the best time for collecting the leaves of A arborescens