Abstract:
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Objective 】The effects of different light times on the growth and development of different leaf vegetables were studied, and the growth and development rules were analyzed.【
Methods 】Radix gendaria, Italian year-round bolt-resistant lettuce 602, Romaine lettuce and four seasons of health were used as experimental materials LED light sources were used to fill light at night with different light times. The effect of extending different fill light times(6, 9, 12 h)on the growth and nutritional quality of hydroponic leafy vegetables was comprehensively evaluated by using the member function method.【
Results 】Reasonable extension of light time could promote the growth rate and improve the nutritional quality of 4 leaf vegetables. The extension of 9 h of supplemental light was more beneficial to accelerate the leaf growth rate and improve the nutritional quality of Italian year-round bolt-resistant lettuce 602. In addition to that, the extension of 12 h of light supplementation was more conducive to promoting the overall growth and development of genda and Roman callie lettuce and improving the nutritional quality. As a result, the maximum leaf length, maximum leaf width, leaf number, vitamin C, soluble sugar and soluble protein of romaine lettuce 602 increased by 15.7%, 6.2%, 10.2%, 50.0%, 24.2% and 2.7%, respectively, when the light duration was extended from 6 h to 9 h. The four seasons health increased by 3.5%, 35.6%, 11.1%, 4.4%, 9.9% and 12.2% respectively. When light duration was extended from 6 to 12 h, plant height, root length, maximum leaf length, maximum leaf width, leaf number and soluble protein increased by 15.6%, 20.3%, 7.1%, 15.6%, 9.3% and 43.5%, respectively. Romaine lettuce rose 18.0%, 14.2%, 3.0%, 15.9%, 20.8%, and 81.1%, respectively.【
Conclusion 】The growth and nutritional quality indexes are the best when Gendaria and Callie lettuce are cultivated for 12 h with extended light supplement, and the growth and nutritional quality indexes are the best when Italian year-round bolt-resistant lettuce 602 is cultivated for 9 h with extended light supplement.