31. The protein may play a role in cell growth and differentiation and act as a negative growth regulator . 32. Ask your nurseryman if there is a plant-growth regulator that could be used on your species of tree. 33. But even growth regulators have drawbacks. 34. However, more recent research suggests that wood fibre can have detrimental affects on " plant growth regulators ". 35. Plant hormones, known as plant growth regulators ( PGRs ) or phytohormones, are chemicals that regulate a plant's growth. 36. Yki also activates expression of the " bantam " microRNA, a positive growth regulator that specifically affects cell number. 37. In contrast to Ras, ARHI works as an inhibitor for cell growth, thus functioning as a negative growth regulator . 38. Classified as a pesticide, it was a plant-growth regulator used on apples to slow ripening and prolong shelf life. 39. Growth regulators ( IAA ) are thought to have a role in cell enlargement since they increases cell wall plasticity.40. However, molecules of IAA are chemically labile in aqueous solution, so it is not used commercially as a plant growth regulator .
