Relationship of fertilizer and periodic drought on biomass allocation in greenhouse-grown sunflower

Abstract

The objective was to analyze organ plasticity in biomass allocation in response to limited resources and its influence on commercial traits of potted sunflower production. Although drought dramatically increased net photosynthetic rate and water-use efficiency, total leaf area, leaf dry mass, and total dry mass with drought stress decreased at rates of 20.9, 21.8, 23.0, and 9.9%, respectively. Irrigation positively affected specific leaf area, stem mass fraction, and root mass fraction. Adversely, fertilizer had a negative effect on stem mass fraction, root mass fraction, and root/shoot ratio. Interestingly, leaf mass fraction was not affected by them. Drought and greater fertilizer amount promoted flower yield and maintained leaf mass fraction stability at the expense of stem and root production. This induced plants to produce a thin stem, poor root system, and weak lodging resistance despite high flower production. This could have significant economic consequences for commercial potted flower production.