If a germinating seed is attached horizontally to a revolving klinostat, what would be the effect on the seedling after three days? The

Explanation

A klinostat rotates a germinating seed slowly, continuously changing the direction of the gravitational pull on the seedling parts. This effectively nullifies the effect of gravity (gravitropism). Therefore, the radicle, which normally exhibits positive gravitropism (grows downwards), will not be able to perceive a constant downward pull and will grow straight without any curvature. The plumule, however, while its negative gravitropism is nullified, will still respond to light (phototropism). If light is present (typically from above in a growing environment), the plumule will exhibit positive phototropism and curve vertically upward towards the light. Therefore, the plumule will curve vertically upward due to phototropism, while the radicle will not show any curvature due to the nullification of gravitropism.