Synergistic effects of foliar potassium supplementation with photoperiod on storage tolerance and taste of fresh cut lettuce

Abstract

Fresh cut lettuce (Lactuca sativa L.) is an important leafy vegetable, due to high perishability, storage tolerance become a critical factor to maintain its quality and taste. This study aimed to determine whether photoperiod duration and potassium fertilizer will boost the taste and the storage tolerance of fresh cut lettuce. A factorial experiment comprising two factors was conducted, involving two photoperiod durations (14h light/day and 12h light/day) and various concentrations of potassium fertilizer (0%, 0.3%, 0.6% and 0.9%) as foliar sprays. For fresh cut lettuce cultivated under a 14-hour photoperiod, applying either 0% or 0.3% potassium enhanced water content, soluble solids accumulation, supported the maintenance of antioxidant enzyme activity stability, and reduced the decay rate during storage. While 0.3% or 0.6% potassium concentration was required to achieve the high quality and storability aim under 12h photoperiod. Current findings may provide a valuable information toward sustainable strategies for enhancing the post-harvest life of fresh cut lettuce with maintained taste and its potential application in post-harvest management of commercial produce.

Keywords: antioxidant; environmental effect; growth; storage; taste.

Figure 1

Water content of fresh cut lettuce cultured at 14h photoperiod (A, B) or 12h photoperiod (C, D) with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. Statistical significances (p<0.05) of values in the same storage time are indicated by different letters.

Figure 2

Soluble solids content of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. The numerical values on the vertical axis of the radar chart represents the soluble solids content (%). Specifically, the maximum scale for soluble solids content is 4.5% in the 14h photoperiod radar chart and 4% in the 12h photoperiod radar chart.

Figure 3

Decay rate of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. Statistical significances (p<0.05) of values in the same storage time are indicated by different letters.

Figure 4

MDA of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. The numerical values on the vertical axis of the radar chart represents the MDA (μmol/g). Specifically, the maximum scale for MDA is 140 μmol/g in the 14h photoperiod radar chart and 150 μmol/g in the 12h photoperiod radar chart.

Figure 5

POD content of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. The numerical values on the vertical axis of the radar chart represents the POD content (μ/g). The maximum scale for POD content is 3.6 μ/g in 14h photoperiod radar chart and 12h photoperiod radar chart.

Figure 6

SOD content of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. The numerical values on the vertical axis of the radar chart represents the SOD content (μ/g). Specifically, the maximum scale for SOD content is 2000 μ/g in the 14h photoperiod radar chart and 2200 μ/g in the 12h photoperiod radar chart.

Figure 7

CAT content of fresh cut lettuce cultured at 14h photoperiod or 12h photoperiod with potassium fertilize of 0%, 0.3%, 0.6% and 0.9%, respectively. The numerical values on the vertical axis of the radar chart represents the CAT content (μ/g). The maximum scale for CAT content is 750 μ/g in 14h photoperiod radar chart and 12h photoperiod radar chart.