Nucellus - seed, Biology

Nucellus - Seed

In a large majority of flowering plants the nucellus is gradually utilized by the endosperm or embryo. In leguminous seeds, for example, the nucellus degenerates completely. Sometimes, as observed in Euphorbia spp., nucellar cells near the micropyle (termed epistase) and chalaza (hypostase) survive longer and may even persist in the mature seed.

In the black pepper fruit the bulk of the volume is occupied by the persistent nucellus, which is also the chief food storage tissue (endosperm is relatively little). Such persisting nucellus in the seed is designated perisperm. In Daphniphyllum himalayense the seed has copious endosperm surrounded by perisperm, which is characterized by the presence of oil droplets and even protein crystals.

 

Posted Date: 1/23/2013 8:03:34 AM | Location : United States







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