Seed priming com Ulva Lactucal L. em sementes cultivadas em análogos de regolito lunar e marciano

Abstract

Due to the imminent nature of human settlement on lunar and/or Martian bases, there is an urgent need to implement and make compatible food production in these environments by optimizing available lunar and Martian regolith resources. In addition, the Martian and lunar economy will depend on the cultivation and marketing of low-cost food resources obtained through sustainable biotechnologies. Macroalgae extracts are considered promising low-cost resources that can be used in seed priming before sowing to promote faster and more uniform germination. The present work experimentally evaluated the effect of different concentrations of the green macroalgae Ulva lactuca L. powder on the germination and growth of the cultivars Capsicum annuum L. (pepper), Lactuca sativa L. (lettuce), Cicer arietinum L. (chickpea) and Pisum sativum L. (pea) in Martian and lunar regolith simulators. The germination and emergence of the seeds were evaluated under controlled greenhouse conditions with the addition of two concentrations of U. lactuca powder (0.2 and 0.4 g.L -1 ). The qualitative chemical analysis of U. lactuca was performed for the purpose of knowledge of its bioactives (alkaloids, terpenoids, phenol, saponins, flavonoids, quinine, and steroids) important as metabolic pathways for the formation of phytohormones. The speed of germination and emergence of the seeds of the cultivars in lunar regolith were higher than those observed in Martian regolith (p < 0.05). In Martian regolith, the best treatment for germination of pea and chickpeas seeds was 0.2 g.L -1 (p= < 0.001; p= 0.006), as well as seedling emergence. In lunar regolith, pea seeds germination peaks were obtained with both treatments (0.2 g.L -1 p= < 0.001 and 0.4 g.L -1 p= 0.001), as well as beak grain seeds (0.2 g.L p= 0.002 and 0.4 g.L -1 ; p= 0.008).-1.The germination percentage of lettuce seeds grown in lunar regolith was better in 0.2 g.L -1 compared to the control (p= 0.010). For the other seeds, there was no significant difference. From the results obtained, we propose using U. lactuca powder as a biostimulant for the studied cultivars, due to the presenceof plant growth regulators (PGRs) that improve germination and seedling emergence under stressful conditions.