Exalbuminous is a botanical term meaning "without endosperm." The word is pronounced as /ɛksəlˈbjumɪnəs/. The prefix "ex-" means out or without, and the suffix "-ous" means possessing the qualities of something. The root word "alb" means white, referring to the white, starchy endosperm that is absent in exalbuminous plants. The word is spelled based on its Latin roots, with the "x" being pronounced as "ks" and the stress falling on the second syllable.
Exalbuminous is an adjective used in the context of botany and refers to a type of seed characteristic. Specifically, exalbuminous seeds are those that lack endosperm, which is a nutrient-rich storage tissue found in the seeds of most flowering plants. This distinct characteristic sets exalbuminous seeds apart from albuminous seeds, which do contain endosperm.
In exalbuminous seeds, the embryo of the plant is developed enough to sustain its growth without relying on external sources of nourishment. When the seed germinates, the embryo utilizes the stored food reserves within its cotyledons to fuel its initial growth until it can establish itself independently through photosynthesis.
This characteristic is advantageous for exalbuminous plants since it allows them to allocate more resources towards producing seeds rather than endosperm. By not requiring endosperm, exalbuminous seeds often have a smaller size compared to albuminous seeds. This can be observed in several notable plant families, such as the legumes (Fabaceae) and the sunflowers (Asteraceae).
Overall, the term exalbuminous is used to describe seeds that lack endosperm and rely on their developed embryos and cotyledons for nourishment during germination and early growth.
Noting a seed without endosperm.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
In bot., applied to a seed which has no distinct albumen, or none but what is contained within the cotyledons themselves.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "exalbuminous" derives from the combination of two Latin words. The first part, "ex", means "out" or "without". The second part, "albumen", refers to "the white of an egg" or "egg white". Therefore, when combined, "exalbuminous" means "without albumen" or "lacking in albumen". This term is often used in botanical contexts to describe seeds that do not have endosperm or albumen, which are the nutrient-rich substances that typically surround the embryo in most seeds.