关键词: 紫外光催化, 甲基橙, 黑磷纳米片, 羟基自由基

Abstract: Dendrocalamopsis oldhami is an important bamboo species for afforestation in south subtropical China, with a broad application prospect in culm and shoot production. In this study, photosynthetic capacity, chlorophyll fluorescence parameters, and growth characteristics of D. oldhamiwere investigated under three shading treatments: no shading as control (full illumination, L₀), singlelayer shading (70% of full illumination, L₁), and two-layer shading (30% of full illumination, L₂). We found that treatment L₁ increased the apparent quantum efficiency and net photosynthetic rate of D. oldhami leaves, while treatment L₂ had the lower values, with significant difference among the three treatments (P<0.05). The dark respiration rate (R_d), light compensation point (LCP), and light saturation point (LSP) declined with decreasing light levels. For the chlorophyll fluorescence parameters, shading significantly increased PSⅡ primary energy conversion efficiency (F_v/F_m), PSⅡ potential activity (F_v/F_o) and electron transport rate (ETR), and decreased photochemical efficiency of PSⅡ (F_v′/F_m′), photochemical quenching (q_P) and nonphotochemical quenching (NPQ). Moreover, shading significantly increasedleaf chlorophyll content (Chla+Chlb) and Chla/Chlb ratio, with a significant difference between treatments L₀ and L₂ (P<0.05). Shading enhanced the growth performance of D. oldhami, with greatest basal diameter in treatment L₁. Leaf area increased with the increases of shading levels. There was no effect of shading on plant height (P>0.05). Thus, D. oldhami has a strong adaptability to weak shading environment and an adjustable inherent mechanism to utilize low intensity light. However, low light intensity would restrict the growth ofD. oldhami container seedlings.

Key words: layered black phosphorus, methyl orange, hydroxyl radical, UV photocatalysis