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Introduction to Flowering plant:

24 января

Flowering plants include several members of the clade commonly referred to as angiosperms. The term "angiosperm" is derived from the Greek words angios (`container, vessel`) and spermatozoa (`seed`), and refers to plants that produce their seeds within a

Flowering plant:

Flowering plants include several members of the clade commonly referred to as angiosperms. The term "angiosperm" is derived from the Greek words angios ('container, vessel') and spermatozoa ('seed'), and refers to plants that produce their seeds within a fruit. The species of flowering plants are huge diversified groups having land plants with 64 orders, 416 families, approximately 13,000 known genera, and 300,000 known species. Angiosperms were formerly called Magnoliophyta.

Like gymnosperms, angiosperms are seed-producing plants. They differ from gymnosperms in characteristics including flower production, endosperm within their seeds, and seeded fruits. During the Carboniferous, the common ancestors of all living gymnosperms were different from the ancestor of flowering plants, with the earliest records of angiosperm pollen dating back to about 134 million years ago. The very first species of flowering plants dates back to 125 million years ago. During the Early Cretaceous, they diversified extensively became widespread 120 million years ago, and replaced conifers as the dominant trees between 60 and 100 million years ago. The houston florists delivery system can deliever houston roses for every day and sunflowers in houston, TX.

Vascular anatomy:

The stems of angiosperms are composed of seven layers as shown on the right. The amount and complexity of tissue formation in flowering plants is greater than that of gymnosperms. In dicotyledons, the vascular bundles of the stem are arranged in such a way that the xylem and phloem form concentric rings. In very short stems the bundles are arranged in an open ring, which separates a central medulla from the outer cortex. In each bundle, separating the xylem and phloem is a layer of meristem or active conformational tissue known as cambium. A complete ring is formed, by the formation of a layer of cambium between the bundles (interfascicular cambium), and a regular periodic increase in thickness results in the development of phloem on the outside and xylem on the inside.

The crushing of soft phloem is done, but the hardwood remains and forms the bulk of the stems and branches of woody perennials. Due to differences in the character of the elements produced at the beginning and end of the season, wood is marked in cross-section in concentric rings, one for each season of growth called an annual ring. Among monocotyledons, bundles are more numerous in young stems and scattered through the ground tissue. They do not have cambium and once formed the stem grows in diameter only in exceptional cases.

 




Дата публикации: 24/01/2022