Effects of fertilization on chlorophyll fluorescence parameters and physiological characteristics of Rubus chingii

To explore the fertilizer requirement of Rubus chingii, and provide a theoretical reference and guidance for its high quality and high yield cultivation in the future.

The effects of different fertilizers fertilizing amounts [low (L), medium (M) and high (H) levels] on the chlorophyll, plant height, chlorophyll fluorescence parameters and related physiological indexes of R. chingii were studied by pot experiment.

Chlorophyll content, plant height, chlorophyll fluorescence parameters and physiological indexes increased with the increase of fertilization amount. Compared with control, the increases of chlorophyll content under NPK fertilization were stable, being 36.3%, 41.3% and 53.4% under L, M and H levels of NPK fertilization, and differences among NPK levels were significant. Compound fertilization significantly increased chlorophyll content, but there was no significant difference among different levels of compound fertilizer. Chlorophyll content was not significantly different between M and H levels of organic fertilizer. There was highly significant correlation between NPK fertilization levels and plant height. Plant heights under NPK fertilization were the highest, the increases were 40.5%, 50.2% and 64.4%, followed by 18.3%, 44.0% and 56.2% with organic fertilization, and then 16.1%, 20.3% and 40.7% with compound fertilization. At different fertilization levels, NPK fertilization resulted in the highest levels of F_v/F_m, Φ_psⅡ and qP. Compound fertilization and organic fertilization levels had significant correlation with four chlorophyll fluorescence parameters. Among three fertilization treatments, qP was the lowest under compound fertilization, while F_v/F_m and Φ_psⅡ were the lowest under organic fertilization. NPK fertilization level had significant correlation with four physiological indexes. At different fertilization levels, NPK fertilization resulted in the highest contents of soluble protein, soluble sugar and proline, and the lowest MDA content. At H level of compound fertilization, the increases of soluble protein and soluble sugar contents were 8.4% and 2.1% respectively, which were the lowest. At H level of organic fertilization, the increases of MDA content was 36.8%, which was the highest.

With the increase of fertilization levels, the chlorophyll content and plant height of R. chingii significantly increased under NPK fertilization, and the chlorophyll fluorescence parameters and physiological indexes also had desirable values.