The formation of gametophyte, from sporophyte, without spore formation or without meiosis is known as :
apospory
apogamy
parthenogenesis
none of these
Anemophillous flowers have :
sessile stigma
small and smooth stigma
coloured flower
large and feathery stigma
To which of the following flower 'synandrous' condition is found?
Sunflower (Helianthus sp)
Gourd (Cucurbita sp)
Pea (Pisum sativum)
Lemon (Citrus sp)
Scientific name of sunflower is
Hibiscus rosa-sinensis
Solanum nigrum
Oryza sativa
Helianthus annuus
Exine of pollen grain is made up o
pectocellulose
lignocellulose
sporopollenin
pollen kit
C.
sporopollenin
Pollen grains are spherical in shape. They are 25-50 micrometres in diameter. It has a prominent two-layered wall. The hard outer layer called the exine is made up of
sporopollenin. It can withstand high temperatures and strong acids and alkali. Pollen grains are well preserved as fossils because of the presence of sporopollenin. Pollen grain exine has prominent apertures called germ pores, where sporopollenin is absent. The inner wall of the pollen grain, intine is a thin and continuous layer made up of cellulose and pectin.