2.2 | Experimental materials and design
A. trifoliata was provided by The Institute of Traditional
Chinese Medicine, College of Agriculture, Guizhou University. The annual
seedlings with strong growth, no diseases and pests, and basically the
same growth were selected as the planting materials and planted in early
April. Soil samples were taken for physical and chemical properties test
(Table 2), and the significance of different habitats in the same base
was analyzed. As showed in Figure 1, the normal habitat is planted
according to the spacing of 2 m × 3 m, while the rocky desertification
habitat was planted according to the actual situation, and was divided
into 10 plots. Natural rainfall, did not add any fertilizer, so that its
natural growth. Six plants with similar growth were randomly selected
from each plot, three of which were used to measure the biomass (every
30 days or so), and the other three were used to measure the secondary
metabolites and related enzymes indexes. When sampling, the stems and
leaves within 1 m of the upper part of the plant and the root within 20
cm of the soil layer were selected as materials, which were stored in
self sealed bags in ice box and quickly brought back to the laboratory
for quick freezing in liquid nitrogen at - 80 ℃.
TABLE 2 The soil physical
and chemical properties in different habitats