Plants which behave as mesophytes in rainy season and as xerophytes in summers are called:

When tropical plants are shifted to temperate climate,they do not grow. This is due to

Match the following:
Column-$A$ | Column-$B$
$(1)$ Auxin | $(I)$ Ripening and maturity of fruits
$(2)$ Gibberellin | $(II)$ Differentiation of xylem elements
$(3)$ Cytokinin | $(III)$ Prevention of genetic and physiological dwarfism
$(4)$ Ethylene | $(IV)$ Found from tumour tissue of tobacco

One hormone hastens the maturity period in juvenile conifers,a second hormone controls xylem differentiation,while the third increases the tolerance of plants to various stresses. They are respectively:

Both ethylene and $ABA$ are responsible for

Name a hormone which:
$(A)$ is gaseous in nature
$(B)$ is responsible for phototropism
$(C)$ induces femaleness in flowers of cucumber
$(D)$ is used for killing weeds (dicots)
$(E)$ induces flowering in long day plants