Alternate wetting and drying irrigation-mediated changes in the growth, photosynthesis and yield of the medicinal plant Tulipa edulis

Tulipa edulis is an important medicinal plant with a variety of anti-cancer properties. There is an urgent need to reduce water consumption in T. edulis under greenhouse cultivation. A greenhouse experiment was performed to study the effect of well-watered (80% of field capacity, Control), persistent drought (50% of field capacity, D) and alternate wetting and drying (50% and 80% of field capacity, AWD) regimes on the growth traits, photosynthetic pigment contents, chlorophyll fluorescence parameters, photosynthetic characteristics and yield of T. edulis. The results showed that compared with the well-watered control, persistent drought inhibited plant growth and yields dramatically, presumably due to the significantly lower photosynthetic rate caused by a decrease in photosynthetic pigments and a reduced chlorophyll fluorescence efficiency (Fv/Fm, Fv/F0). In contrast, the AWD plants showed a capacity for photosynthesis comparable to the well-watered control, which could be associated with similar photosynthetic pigment levels and chlorophyll fluorescence parameters (Fv/Fm, Fv/F0). AWD reduced the irrigation water input by 25.09% while leading to comparable yields and increased water productivity by 21.21% compared with the well-watered control. The results suggested that an alternate wetting and drying (50% and 80% of field capacity) regime can be an effective means of saving water, promoting bulb production, and improving water production for T. edulis. (C) 2014 Elsevier B.V. All rights reserved.