Effect of Seed Priming with Chitosan Hydrolysate on Lettuce (Lactuca sativa) Growth Parameters

Abstract

Seed priming increases germination, yield, and resistance to abiotic factors and phytopathogens. Chitosan is considered an ecofriendly growth stimulant and crop protection agent. Chitosan hydrolysate (CH) is an unfractionated product of hydrolysis of high-molecular-weight crab shell chitosan with a molecular weight of 1040 kDa and a degree of deacetylation of 85% with nitric acid. The average molecular weight of the main fraction in CH was 39 kDa. Lettuce seeds were soaked in 0.01–1 mg/mL CH for 6 h before sowing. The effects of CH on seed germination, plant morphology, and biochemical indicators at different growth stages were evaluated. Under the 0.1 mg/mL CH treatment, earlier seed germination was detected compared to the control. Increased root branching was observed, along with 100% and 67% increases in fresh weight (FW) at the 24th and 38th days after sowing (DAS), respectively. An increase in the shoot FW was found in CH-treated plants (33% and 4% at the 24th and 38th DAS, respectively). Significant increases in chlorophyll and carotenoid content compared to the control were observed at the 10th DAS. There were no significant differences in the activity of phenylalanine ammonia-lyase, polyphenol oxidase, β-1,3-glucanase, and chitinase at the 24th and 38th DAS. Seed priming with CH could increase the yield and uniformity of plants within the group. This effect is important for commercial vegetable production.

Phenylalanine Ammonia-Lyase-Mediated Differential Response of Tomato (Solanum lycopersicum L.) Cultivars with Different Stress Tolerance to Treatment with Low-Molecular-Weight Chitosan

“…We also conducted studies on lettuce (Lactuca sativa). Treatment of lettuce seeds with chitosan hydrolysate revealed better conditions for the seedlings compared to the control [60]. Similar results were reported in soybean (Glycine max) [39], cucumber (Cucumis sativus) [12], sunflower (Helianthus annuus) [41], and other plants [10,13,38,[61][62][63].…”

Priming methods affected deterioration speed of primed rice seeds by regulating reactive oxygen species accumulation, seed respiration and starch degradation

“…The basic procedures of seed priming include the controlled seed hydration to induce various metabolic processes during the early phase of germination, and the drying of primed seeds to an initial moisture content before radicle emergence ( Heydecker and Gibbins, 1978 ). In recent years, the effects of seed priming have been intensively studied in rice, maize, lettuce, tomato and other crops and the benefits of seed priming to increase seed germination, uniformity of seedling emergence, seedling vigor, and to enhance stress tolerance have been widely reported ( Rehman et al., 2015 ; Nawaz et al., 2016 ; Imran et al., 2017 ; Petronilio et al., 2021 ; Lyalina et al., 2023 ). Meanwhile, rice (Oryza sativa L.) is the world’s second largest source of food and is grown on 163.2 million ha, with an average annual production of 740.9 million tons worldwide ( FAOSTAT, 2014 ).…”