Introduction

• Germination is the emergence and development of a seedling from the seed embryo that can produce a normal plant under favorable conditions.
• Germination is the term used to designate those processes beginning with the imbibition of water by dry seeds and ending when a portion of the embryo penetrates the seed coat.
• The emergence phase of growth begins when the embryo penetrates the seed coat and ends when the shoot system can sustain growth through the process of photosynthesis.

Longevity of seed

• It is the duration of viability of the seeds.
• In general, seed viability is governed by external environmental factors to which the seed is exposed following maturation.
• According to longevity, seeds are categorized into 3 classes;

1. Macrobiotic seeds (retain viability for >15 years often due to waterproof seed coat): Ex- Lotus (Nelumbo nucifera), Chenopodium album.
2. Mesobiotic seeds (retain viability for 3-15 years)
3. Microbiotic seeds (retain viability for <3 years): Ex-Oxalis seed die within 3 days.