Effect of putrescine on dried flower yield and essential oil components changes of Chamomile Plants (Matricaria chamomilla L.) under different moisture regimes

In order to improve the tolerance of German chamomile cultivars to moisture regimes, this factorial experiment was conducted in a randomized complete block design in three replicates, in the agricultural college of Tehran university in 2013-14 cropping season.

Experimental treatments included moisture regimes (control and severe stress, i.e., 13% and 57% of allowable soil moisture depletion, respectively), two cultivars of chamomile (German Badgold and Hungarian modified cultivar) and foliar application with putrescine (with a concentration of 0.1 mM and 45 days after transfer to the pots).

The results showed that the simple effect of putrescine polyamine on plant height and biomass was significant at 1% level and on harvest index at 5% level. Plant height did not have a significant response to putrescine in control conditions, but in severe stress (57% of soil water depletion), the effect of foliar application showed a significant boost (13.5%). The simple effect of putrescine on percentage and essential oil yield (at 1% level) was significant. Also, the interaction effect of moisture regimes and foliar application with putrescine on essential oil content (at 5% level) and essential oil yield (at 1% level) was considerable. Under optimal moisture conditions (13% of soil water depletion), putrescine resulted in a significant increase in essential oil content by 38%. But its foliar application in drought stress increased the essential oil content by only 4%. Foliar application of putrescine reduced the amount of farnesene and bisabolol B oxide in both conditions. Another important compound was bisabolone oxide A, wherein putrescine treatment had a positive effect on its accumulation so that under favorable conditions of moisture its concentration increased by 87%, but under conditions of stress its effect decreased, showing only 35%.

The use of putresin in chamomile is economically justified due to increased tolerance to dehydration stress and increased target secondary metabolites.