Notulae Botanicae Horti Agrobotanici Cluj-Napoca (Sep 2024)

PGPR alleviated the negative effects of low temperature and low light stress on the growth and physiology of violet plants

  • Wei LI,
  • Yu-Lu SONG,
  • Yi-Dan ZHANG,
  • Shao-Xia GUO

DOI
https://doi.org/10.15835/nbha52313273
Journal volume & issue
Vol. 52, no. 3

Abstract

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Plants in greenhouses are often exposed to low temperature and low light conditions in the winter, and this has a major effect on flower cultivation. Inoculation of plant growth-promoting rhizobacteria (PGPR) can improve the growth of plants under stress. Here, we examined the effects of Pseudomonas fluorescens on the growth, photosynthesis, chlorophyll fluorescence parameters, and antioxidant enzyme systems of violet plants (Matthiola incana) exposed to normal temperature and normal light intensity (18 °C/11 °C, 500 μmol·m-2·s-1, NN), low temperature and normal light intensity (4 °C/1 °C, 500 μmol·m-2·s-1, LN), normal temperature and low light intensity (18 °C/11°C, 100 μmol·m-2·s-1, NL), and low temperature and low light intensity (4 °C/1 °C, 100 μmol·m-2·s-1, LL). The results showed that the plant height, stem diameter, leaf area, shoot fresh/dry weight, and underground fresh/dry weight of violet inoculated with PGPR were 40%, 17%, 13%, 25%, 41%, 30%, and 38% higher than the control, respectively. In addition, the total root length, mean root diameter, number of root tips, number of bifurcated root tips, and root vigor were 24%, 23%, 14%, 30%, and 21% higher in the inoculated group than in the control group, respectively. PGPR promoted chlorophyll accumulation in plants, and the net photosynthetic rate of violets was 32% higher in plants inoculated with PGPR than in control plants. PGPR also significantly promoted the maximum photochemical conversion efficiency of photosystem II (PSII) and the potential activity of PSII under UV light. After inoculation with PGPR, the content of MDA decreased by 16.8%, and the activities of superoxide dismutase and peroxidase increased by 19.2% and 20.0%, respectively. Therefore, PGPR can promote the growth of violet plants by increasing the photosynthetic capacity, activating the antioxidant enzyme system, and reducing damage induced by exposure to low light intensity.

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