Influence of Bamboo Charcoal Application on Chlorophyll Content and Fluorescence Parameters of Cabbage

Key words: 
• bamboo charcoal，cabbage，chlorophyll content，fluorescence parameter，organic agriculture /
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Abstract: To reveal the effects of bamboo charcoal application on cabbage chlorophyll content and fluores‐cence parameters and to determine the optimum rate of charcoal organic fertilizer for cabbage ,three treat‐ments ,i.e. control (CK) ,moderate charcoal (MC) and severe charcoal (SC) ,were made in a field test , and chlorophyll content (SPAD value) and fluorescence parameters of the leaves at the rosette and heading periods of the plants were measured .Chlorophyll content was highly significantly higher at the heading pe‐riod than at the rosette period (pCK>SC .The initial minimum fluores‐cence Fo ,the initial maximum fluorescence Fm ,the maximum photochemical efficiency of PSⅡ Fv/Fm , the potential activity of PSⅡ Fv/Fo and non‐photochemical quenching coefficient qN at the heading period were lower than those at the heading period ,but PSⅡ actual photochemical efficiency ΦPSⅡ and photo‐chemical quenching qP at the heading period were higher than those at the rosette period .Increased bam‐boo charcoal application resulted in a similar trend in the above seven parameters at both periods ,i.e. Fo and qN exhibited a V‐shaped variation ,and Fm , Fv/Fm , Fv/Fo ,ΦPS Ⅱ and qP an inverted V‐shaped variation ,but there was no significance for ΦPSⅡ or qP (p>0.05) .These results indicated that the pho‐tosynthesis at the heading period was higher than that at the rosette period .Increasing bamboo charcoal application rate from CK to MC contributed to raising chlorophyll content ,enhancing energy efficiency , reducing plant heat dissipation and improving plant photosynthesis .However ,with further increase in charcoal rate to SC ,chlorophyll content and energy use rate decreased ,heat dissipation increased and ,as a result ,photosynthesis was inhibited .In conclusion ,cabbage grew most vigorously in the Treatment MC in this experiment ,indicating that MC is the optimum application rate of bamboo charcoal manure in cabbage production .