Growth rings are formed due to activity of :
extrastelar cambium
intrastelar cambium
interstelar cambium
both 'b' and 'c'
D.
both 'b' and 'c'
Intrafascicular or intrastelar cambium is present between xylem and phloem in dicot stem and roots. Pith rays, present between the edges of intrafascicular cambium, divide to form a new cambium strip between the two vascular bundle i.e. interfascicular cambium. Thus, inter and intra fascicular cambium together forms a complete cambium ring, called as vascular cambium, which forms secondary xylem on inner side and secondary phloem on outer side. Differential cambial activity during autumn and spring season result in narrow and wide secondary xylem rings respectively, which together forms the annual growth ring. Thus, annual growth ring is derived from vascular cambium, which is derived from inter and intrastelar cambium.
Which of the following does not match ?
Muscular movement - ATP
Heart - pace maker
Monocyte - haemoglobin
Nerve impulse - acetylcholine
Which of the following taxonomist described classification of plant kingdom in "Families of flowering plants" ?
Cronquist
Takhtajan
Benson
Hutchinson
Largest number of chloroplast is found in :
palisade tissue
spongy tissue
transfusion tissue
bundle sheath cells
Rarely among angiosperms the pollen grains influenced the endosperm. This is called as :
Metaxenia
Nemec phenomenon
Xenia
Mesogamy
Defect in amino acid metabolism may results in :
albinism
porphyria
Wilson's disease
phenylketonuria
