HOSEIN nAZARLI; ali naderi arefi
Abstract
Objective: 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.
Methods: Experimental treatments ...
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Objective: 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.
Methods: 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).
Results: 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%.
Conclusion: The use of putresin in chamomile is economically justified due to increased tolerance to dehydration stress and increased target secondary metabolites.