Question

Which tissue remains less active in winter?

• A. Cambium
• B. Parenchyma
• C. Sclerenchyma
• D. None of the above

Answer 1

The correct option is A Cambium

In dicot stems, the cambium, which is present between primary xylem and primary phloem is called intrafascicular cambium. The cells of medullary rays near these intrafascicular cambium become meristematic and form interfascicular cambium. This leads to the formation of a continuous ring of cambium.

The cambial ring becomes active and starts cutting off new cells; both on the inner and the outer sides. The cells which are cut off towards the pith mature into secondary xylem. The cells which are cut off towards the periphery mature into secondary phloem. The cambium is usually more active on the inner side than on the outer side.

Various physiological and environmental factors control the activity of cambium. Climatic conditions are not uniform through the year; in temperate regions. Cambium is very active during the spring season, while it is less active during the winters. Hence, during spring; a large number of xylem elements are formed which have wider vessels. During winter, fewer xylem elements are formed which have narrow vessels. The wood formed during summer is called as spring wood or early wood, while the wood formed during winter is called as autumn wood or late wood.