Sugarcane leaf shows the classical arrangement of cells, which defines a C4 species. Vascular bundles consist of xylem, phloem and fibres, surrounded by an outer layer ofsclereids and an inner ring of stone cells asso...Sugarcane leaf shows the classical arrangement of cells, which defines a C4 species. Vascular bundles consist of xylem, phloem and fibres, surrounded by an outer layer ofsclereids and an inner ring of stone cells associated with the phloem. Some sclereids located below and above the vascular bundles act as docking cells and connect the vascular bundle to the internal surfaces of upper and lower layers of the epidermis. A compact mass ofsclereids occupies the total internal volume of the leaf edge. Neither docking cells nor the internal mass of sclereids in the edge were markedly coloured by phloroglucinol, indicating the absence of lignin in their cell walls. However, such staining indicated that fibres of the vascular bundle and the external layer of sclereids were strongly lignified. Incubation of leaf discs with an virulence factors produced by the pathogen Sporisorium scitamineum increased the thickness of the lignified cell walls of sclereids as well as the mid and small xylem vessels, as a possible mechanical defence response to the potential entry of the pathogen. This mechanism was mainly revealed for the resistant cv. Mayari 55-14, whereas lignification decreased for the susceptible cv. B 42231.展开更多
文摘Sugarcane leaf shows the classical arrangement of cells, which defines a C4 species. Vascular bundles consist of xylem, phloem and fibres, surrounded by an outer layer ofsclereids and an inner ring of stone cells associated with the phloem. Some sclereids located below and above the vascular bundles act as docking cells and connect the vascular bundle to the internal surfaces of upper and lower layers of the epidermis. A compact mass ofsclereids occupies the total internal volume of the leaf edge. Neither docking cells nor the internal mass of sclereids in the edge were markedly coloured by phloroglucinol, indicating the absence of lignin in their cell walls. However, such staining indicated that fibres of the vascular bundle and the external layer of sclereids were strongly lignified. Incubation of leaf discs with an virulence factors produced by the pathogen Sporisorium scitamineum increased the thickness of the lignified cell walls of sclereids as well as the mid and small xylem vessels, as a possible mechanical defence response to the potential entry of the pathogen. This mechanism was mainly revealed for the resistant cv. Mayari 55-14, whereas lignification decreased for the susceptible cv. B 42231.
