Plant Reproduction and Germination

Bryophytes lack seeds and vascular tissues.

Pteridophytes do not produce seeds.

Seeds of angiosperms are enclosed within the fruits.

Cotyledons are also called seed leaves.

If seeds sense light, they will germinate using their Pfr form. Pfr absorbs at a peak of 730 nm. The Pfr form is the active form that initiates biological responses. When Pfr absorbs far red light, it is converted to the Pr form.

The word "gymnosperm" comes from the Greek word gymnospermos, meaning "naked seeds". In these, the ovules or seeds are not enclosed in an ovary.

Seed dormancy is defined as a state in which seeds are prevented from germinating even under environmental conditions normally favourable for germination. The torpedo-shaped seed of a mangrove (Rhizophora maritima) is an exception. It germinates while still on the mother plant. When they fall, seed penetrates securely into soft mud flats.

Plumule is called future shoot of a germinating seed.

The development of seedless fruit in an unfertilised flower is called parthenocarpy.

A loment (or lomentum) is a type of indehiscent legume fruit that breaks apart at constrictions occurring between segments, so that each segment contains one seed.

In sensor mechanism, seeds remain arrested inside the ovary even after maturity. They wait for the brisk wind to produce further motion in the fruit.

After fertilisation, the other parts of the flower fall off as they are used for attracting insects, etc. for pollination. Seeds are enclosed in a protective seed coat. The seeds are formed from the ovules. Insects are agents of pollination.

 The seeds, which are dispersed by water, have floating ability and spongy or fibrous outer coating.

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An enzyme that can stimulate germination of barley seeds is α-amylase.