Spraying of which of the following phytohormone on juvenile conifers helps in hastening the maturity period, that leads to early seed production?

Spraying gibberellic acid (GA) on juvenile conifers can help in hastening the maturity period, leading to early seed production.GA is a phytohormone that is involved in promoting stem elongation, germination and flowering in plants. In conifers, GA can stimulate the formation of reproductive structures and help in the transition from the juvenile to the adult phase of growth. 

(1) ABA plays a role in regulating plant responses to stress and maintaining plant water balance. ABA is synthesized in response to stress conditions, such as drought, high salinity and extreme temperatures, and it helps plants to cope with these stresses by reducing water loss and promoting water uptake. ABA also plays a role in seed dormancy as well as in the regulation of stomatal aperture.

(2) Indole-3-butyric acid is often used as a rooting hormone to stimulate root formation in plant cuttings. 

(4) Zeatin is involved in various physiological processes, such as nutrient uptake, seed germination and stress responses. It also delays senescence by promoting chloroplast development and the synthesis of photosynthetic pigments, which helps to increase the yield of crops.