Question : Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms

Question : Select one of the following pairs of important features dis

1.	Question : Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms
Answer» ABSENCE of resin duct and leaf venation presence of vessel elements and absence of archegonia perianth and two integuments embryo development and apical meristem Solution :(b) The presence of vessels in the xylem is an angiospermic character found in Gnetum which distinguish it from Cycas and Pinus.Gnetum resembles angiosperms in many other aspects also like(i)The leavesin Gnetum have reticulate venation that is an angiospermic character.(ii)In Gnetum female gametophyte is only partly cellular before fertilisation and becomes completely cellular only after fertilisation Some of tthhe free nuclei act as EGGS as there are no archegonia. The short APICES in Gnetum and angiosperms show a distinctt tunicaand corpus configuration.The cortex of stem of Pinus is traverse by large resin ducts or canals.Each duct or canal is lined by a layer of thin walled parenchymatous glandular secretory cells CONSTITUTING epithelium. The epithelial cells secrete resin into canal.Resin is the chief source of TERPENTINE.