Plant Reproduction and Germination

Germ tube is formed of intine layer.

Fusion of egg cell and polar nuclei with two distinct sperms is called double fertilisation.

Suspensor cell acts as a feeding organ of the embryo during its development.

A placentation that consists of a single compartment without septa and ovules attached to a central column that arises directly from the floral apex is called free central placentation.

Egg apparatus consist of a large central egg cell and two lateral small synergids.

There are 7 cells in an embryo sac.

Syngamy is the fusion of male gamete (sperm) with the female gamete (egg) to form a zygote. External fertilization occurs outside the body (like in frogs), while implantation happens after fertilization.

Fusion of male and female gametes in plants, called as fertilization. It does not require sunlight.

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Cycas is a gymnosperm. This term is derived from two Greek words: Gymno – meaning naked and Sperma – meaning seed. The plants of this group bear naked seeds and are usually perennial, evergreen and woody.

Ferns are seedless vascular plants that reproduce via spores. Angiosperms and gymnosperms both produce seeds, while dicotyledons are a subclass of angiosperms characterized by two cotyledons.

Pteridophytes (ferns) have vascular tissue but reproduce via spores, not seeds. Bryophytes lack vascular tissue, while gymnosperms and angiosperms both have seeds. Pteridophytes represent an intermediate stage with vascular tissue but seedless reproduction.

Gymnosperms have seeds but lack flowers and fruits - their seeds are 'naked' (not enclosed in ovaries). Angiosperms have both seeds and flowers. Bryophytes and pteridophytes reproduce via spores and don't produce seeds. Only gymnosperms fit this description.

Pines are gymnosperms, so their seeds are exposed in cones, not enclosed in fruits. Pines do have seeds, vascular tissue, and differentiated plant bodies. The absence of fruits is characteristic of all gymnosperms, which distinguishes them from angiosperms.

Gymnosperms are characterized by seeds produced in cones (strobili). They don't produce flowers, their seeds are naked (not in fruits), and they have differentiated plant bodies. The cone is the reproductive structure that defines gymnosperms like pines and cycads.