Which one of the following is heterosporous?
Dryopteris
Salvinia
Adiantum
Adiantum
B.
Salvinia
Heterospory is the production of spores of two different sizes and two different developmental patterns. Small spores are called microspores and larger as megaspore. Microspores germinate to produce the male gametophyte or microgametophyte that bear male sex organs while megaspores germinate to form female gametophyte or megagametophytes that bear archegonia or female sex organs. It is most important evolutionary development in the vascular plants because it has ultimately lead to seed development eg, Selaginella, Marselia Salvinia, Azolla, isoetes.
Dryopteris is homosporous a 32-64 haploid spores are produced in each sporangium.
Adiantum is also homosporous. The spores are the pioneer structures of the gametophytic generation.
The blood calcium level is lowered by the deficiency of
parathormone
thyroxine
calcitonin
calcitonin
Dry indehiscent single-seeded fruit formed from bicarpellary syncarpous inferior ovary is
Caryopsis
cypsela
Adiantum
Adiantum
Which one of the following is the correct difference between rod cells and cone cells of our retina?
|
Features |
Rod cells |
Cone cells |
|
Visual acuity |
High |
Low |
|
Features |
Rod cells |
Cone cells |
|
Visual Pigment contained |
Iodeosin |
Rhodopsin |
|
Features |
Rod cells |
Cone cells |
|
Overall function |
Vision in poor light |
Colour vision and detailed vision in bright light |
|
Features |
Rod cells |
Cone cells |
|
Overall function |
Vision in poor light |
Colour vision and detailed vision in bright light |
Which one of the following is linked to the discovery of Bordeaux mixture as a popular fungicide?
Bacterial leaf blight of rice
Downy mildew of grapes
Loose smut of wheat
Loose smut of wheat
Which one of the followings in birds, indicates their reptilian ancestry?
Scales on their hind limbs
Four chambered heart
Two special chambers crop and gizzard in their digestive tract
The rupture and fractionation do not usually occur in the water column in vessel/tracheids during the ascent of sap because of
lignified thick walls
cohesion and adhesion
weak gravitational pull
weak gravitational pull
The fleshy receptacle of syconus of fig encloses a number of
achenes
samaras
berries
berries
The length of different internodes in a culm of sugarcane is variable because of
shoot apical meristem
position of axillary buds
size of leaf lamina at the node below each internode
size of leaf lamina at the node below each internode
