Norepinephrine induces flower-inducing substance
In human, norepinephrine (NE) acts directly on coronary vessels to cause vasodilation and improve blood supply to the heart (Papadopoulos et al., 2010). The noradrenergic system serves multiple brain functions including arousal, attention, mood, learning, memory and stress response (Sofuoglu, & Sewell, 2009). Moreover, more evidences have even shown the relationship between neuroprotective disease and norepinephrine (Moret, & Briley, 2011).
High levels of allegedly animal hormone, epinephrine and norepinephrine, have been also detected in peyote (Kulma, & Szopa, 2007). Lower in oranges, apples, tomatoes, eggplants, spinach, beans, and peas (Feldman, Lee, & Castleberry, 1987). And they play in corresponding regulation of plant physiology. Flowering is a vital physiological phenomenon of plants. Flower-inducing substance (FIS) could be induced by many factors. Studies have shown that NE could interact with FIS to induce flowering in plant. Lemna paucicostata which had been immersed in NE solution (2 mM) had strong FIS activity (Yokoyama et al., 2000). The active component in flower-inducing substance is identified as tyrosine, which means FIS is derived from NE upon contact with the lemna(Yamaguchi, 2001). However, the functional and regulatory mechanisms of NE corresponding with FIS remain to be elucidated.
Furthermore, NE and epinephrine have similar physiological effects in plants due to similar chemical structures (Kulma, & Szopa, 2007). NE in 50 mM and epinephrine in 100 mM are demonstrated to stimulate ethylene synthesis in sugarbeet (Elstner et al., 1976). The same effects were observed in orchardgrass and potato cell culture (Kuklin, & Conger, 1995; Dai, Michaels, & Flores, 1993). There may be an interaction between endogenous plant hormones and them. Moreover, norepinephrine is believed to be a precursor for secondary alkaloids, such as berberastine (Szopa, Wilczyński, Fiehn, Wenczel, & Willmitzer, 2001). However, most of these studies were done decades ago. Further confirmation is necessary with more convincing methods developed recently (Kulma, & Szopa, 2007).