Aquaporins-mediated water availability in substrates for cannabis cultivation in relation to CBD yield

Abstract

Aims: The objective of this study was to identify the most suitable substrate for Cannabis sativa L. cultivation based on its effects on water relations and Cannabidiol (CBD) production. Methods: Biomass, physiological parameters, minerals, changes in the expression levels of plasma membrane intrinsic Proteins (PIP) and CBD concentration was measured in C. sativa (var. Tiborszallasi) plants cultivated on 5 substrates with different physical–chemical characteristics. Results: The substrates available water (AW) was the main factor affecting growth and production. The efficiency of the water use was governed fundamentally by transpiration. Experimental substrates(S) 1 and 3 (S1 and S3) were those in which the plants grew optimally and allows plants to invest energy in secondary metabolites production acquiring high levels of CBD. The plants grown in S2 and S5, composed by coconut fiber and perlite, showed the lowest growth in agreement with low transpiration rates which reduce the water uptake. S5 substrate, with some available water (AW) still present, is forcing plants to invest energy in improving water and nutrient transport, as observed by the high levels of nutrients in planta and PIPs expression levels. S4 plants presented the highest inflorescence production and CBD content, which can be attributed to plant stress due to the low levels of AW and high pH and electrical conductivity (EC). Conclusion: The absorption of water and minerals by plants has been affected by PIP-mediated water transport, playing key roles for the optimal utilization of the water present in the substrates, with specific isoforms involved in these responses.