Unidade VI
Translocação de Solutos
Prof. José Vieira Silva
2012
UFAL – Campus Arapiraca
Curso Agronomia
Disciplina de Fisiologia Vegetal
Unidade VI– Translocação de solutos pelo floema
1 – Introdução
2 – Vias de translocação
3 – Padrões de translocação (fonte para o dreno)
4 – Material translocado pelo floema
5 – Carregamento do floema
6 – Descarregamento do floema
7 – Mecanismo de translocação pelo floema
8 – Alocação e partição de fotoassimilados
Caption: Nasturtium stem. Coloured scanning electron
micrograph (SEM) of a freeze-fractured Nasturtium (Tropaeolum
sp.) stem, showing numerous vascular bundles (such as at upper
centre) with an inner xylem (pink) and outer phloem (orange).
Magnification: x100 when printed at 10 centimetres wide.
Caption: Maize root. Polarised light micrograph of a
section through the root of a maize plant (Zea mays)
showing a vascular cylinder. The cylinder is comprised of a
central cluster of parenchyma cells, surrounded by fused
vascular bundles and the endodermis. The largest vessels
seen here are metaxylem, part of the xylem tissue in the
vascular bundles. Xylem transports water and mineral
nutrients from the roots throughout the plant, while phloem,
the other component of the bundles, transports
carbohydrates and plant hormones.
Caption: Monocotyledon leaf. Illustration showing the anatomy and cell structure of a monocotyledon leaf. The lower surface of
the leaf is seen at top. Stomata (brown, pores) are present on the lower epidermis through which gaseous exchange occurs.
Under the one-cell thick epidermis, spongy mesophyll cells are found loosely packed (grey). Leaf veins occur in parallel in
monocotyledons. Here, two veins (vascular bundles) are seen among mesophyll cells. Schlerenchyma sheath cells (yellow)
strengthen the vein; within the sheath are xylem (pink) and phloem (white) cells which transport water and nutrients.
Anelamento do Caule ou Anel de Malpighi Como proceder e suas implicações
Experimento realizado pelo
biólogo italiano Marcelo
Malpighi, em 1679.
Caption: Dicotyledon plant stem. Light
micrograph of a longitudinal radial section
through a typical dicotyledon stem. The
section has passed through a vascular
bundle and other stem tissue (some of
which have ring thickening, red). The
tissue layers at right are mostly xylem and
parenchyma. There is also a layer of
cambium (light blue, centre). Several rows
of phloem sieve tubes (yellow-green) are at
centre left. At left are large parenchyma
cells (blue) of the inner cortex of the stem.
Magnification: x45.
Caption: Castor oil stem. Light micrograph
of a longitudinal section through the stem
of a castor oil (Ricinus communis) plant. At
right are large and small parenchyma cells
(blue). Immediately to their left are two
rows of proto-xylem vessels and one row
of spiral meta-xylem (both red), which
transport water around the plant. To the left
of this is a bundle of phloem fibres (red)
sandwiched between two groups of phloem
cells (blue). Magnification: x45