[Effects of soil bulk density on growth, physiology and quality of Glechoma longituba]

Through the determination of the growth, physiological and active components of Glechoma longituba, the effect of soil bulk density on growth and quality of G. longituba was explored. Through pot experiment, six different bulk density treatments were set for 0.8, 0.9, 1.0, 1.1, 1.2, 1.3 g·cm⁻³ , the growth index, physiological index and the content of active components were determined. The results showed that the growth indexes and biomass of G. longituba firstly increased and then decreased with the increase of soil bulk density. The dry weight of G. longituba achieved the maximum 5.70 g in the treatment of 1.0 g·cm⁻³ . The photosynthetic pigments, soluble sugars and free amino acids firstly increased and then decreased with the increase of soil bulk density. The suitable soil bulk density was beneficial to the accumulation of photosynthetic pigment, soluble protein and free amino acid synthesis. The content of malondialdehyde increased gradually with the increase of soil bulk density. The contents of ethanol-soluble extractives of G. longituba were greater than 25%, meeting its quality criterionin Chinese Pharmacopoeia 2015, achieved the maximum of 40.66% in the treatment of 1.0 g·cm⁻³ . The total flavonoids content of G. longituba increased gradually with the increase of soil bulk density, triterpenic acid and phenolic acids decreased gradually with the increase of soil bulk density. Soil bulk density has a significant effect on the growth and quality of G. longituba, and it is conducive to the growth and its medicinal quality at the soil bulk density of 1.0 g·cm⁻³.