Double fertilization is the fusion of one male gamete with the egg cell and other with the two polar nuclei to form zygote and the endosperm respectively at the same time .This double fertilization present only in angiosperm in the plant kingdom.
CHARACTERSTICS OF ANGIOSPERMS Read More »
Gymnosperms are adapted to land conditions because :
•1.Vascular tissue is present.
•2.Cambium in vascular tissue for secondary growth so bark is produced.
•3.Pollen grain production in large no. to ensure anemophily.
•4.Development of female gametophyte inside ovule.
•5.Formation of seed to protect the embryo in it.
•6.No need of external water for fertilization.
GYMNOSPERM CHARACTERSTICS AND LIFE CYCLE Read More »
HAPLONTIC LIFE CYCLE: In this the main plant body is haploid gametophyte which is dominant phase in life of plant .This gametophyte produces gametes which fuse to form diploid zygote ( sporophyte) which produces spores by meiosis these haploid spore now form main plant body gametophyte. Ex. Spirogyra,Ulothrix etc.
Selaginella : (spike moss) These plants are capable of flexing their branches & roll to assume the shape of balls under prolonged dry conditions but when dipped in water or moistened they resume their normal form hence called resurrection plants.
Chlorella and chlamydomonas are used in sewage disposal.
•#Unicellular green algae Ex. Chlorella used to provide oxygen during space flights.
•#Alginic acid is obtained from giant brown algae or kelps in India from Sargassum it yields alginate which used as emulsifier ,thickner or to stop bleeding.
•#Agar is obtained from Gelidium ,Chondrus etc. used in jellies creams bakery leather and textile industries act as laxative.
•# Carrageenin is obtained from Chondrus Used in food industry and as blood coagulant.
•#Extract of Corallina is used for kidney treatment.
