differentitate

1)crosspollination and self pollination

2)tuber and rhizome

 

1. Differences between self-pollination and cross-pollination:

Self-pollination	Cross-pollination
It is the transfer of pollen grains from the anther to the stigma of the same flower.	It is the transfer of pollen grains from the anther of one flower to the stigma of another flower of a different plant of the same species.
It does not require any external agent, such as wind, water and insects, to carry out pollination.	It requires an external agent for pollination to occur.
It can take place even when the flower is closed.	It can occur only when the flower is open.
In self-pollinated flowers, the anther and stigma mature at the same time.	In cross-pollinated flowers, the anther and stigma mature at different times.
It preserves parental characters	It does not preserve parental characters.
New varieties are not possible.	New varieties can be produced.
As new variations are not possible, the offspring cannot adapt to changing environmental conditions.	As new variations are possible, the offspring are healthier and are able to adapt to changing environmental conditions.

2. Differences between tuber and rhizome:

Rhizome	Tuber
Stout, dorsoventrally flattened underground stem	Swollen, underground stem
Dorsoventrally flattened	Spherical, oblong or oval
Less stouter than tubers	More stouter than rhizomes
Nodes bear adventitious root on the lower side	Nodes do not bear roots
Buds are present in the axils of scaly leaves and also as terminal buds	Buds in the form of eyes present on the surface