caa a22 4500 605481032 CHVBK 20210128100419.0 cr unu---uuuuu 210128e20150601xx s 000 0 eng 10.1007/s11099-015-0083-8 doi (NATIONALLICENCE)springer-10.1007/s11099-015-0083-8 The importance of blue light for leaf area expansion, development of photosynthetic apparatus, and chloroplast ultrastructure of Cucumis sativus grown under weak light [Elektronische Daten] [X. Wang, X. Xu, J. Cui] The objective of this study was to evaluate the significance of blue light (B) in the growth and photosynthetic capacity of cucumber. Gas exchange, chlorophyll (Chl) fluorescence kinetics, chloroplast ultrastructure, and leaf growth were investigated to explore the influence of three different light qualities of light emitting diodes (LEDs) on plant morphogenesis and the development of photosynthetic apparatus in cucumber (Cucumis sativus) leaves from emergence to full expansion under weak light [50 μmol(photon) m−2 s−1]. We found that B could significantly increase the leaf area (LA), shoot elongation, Chl a/b, net photosynthetic rate, and stomatal conductance (g s). In addition, the comparisons of maximal quantum yield of PSII photochemistry and the photosynthetic performance index between B-, W (white light)-, and R (red light)-grown leaves suggested that B was essential for the development of photosynthetic apparatus under weak light. B-grown leaves had the lowest Chl content under weak light, however, they had well-developed chloroplasts with the highest degree of stacked lamellae and the lowest starch accumulation. This could explain to a considerable extent the highest net photosynthetic rate per Chl unit. The results demonstrated that B optimized photosynthetic performance by improving the photosynthetic rate, increasing LA, and prolonging active photosynthesis duration under low irradiance. Therefore B is necessary to ensure healthy development of chloroplasts and highly efficient photosynthetic functions in cucumbers under a weak light environment. More importantly, our study also provided theoretical and technical support for the development of light environmental control technology. The Institute of Experimental Botany, 2015 fluorescence transient nationallicence grana nationallicence JIP test nationallicence photosynthetic characteristics nationallicence B : blue LEDs nationallicence Chl : chlorophyll nationallicence DM : dry mass nationallicence Fv/Fm : maximal quantum yield of PSII photochemistry nationallicence g m : apparent mesophyll conductance nationallicence g s : stomatal conductance nationallicence LA : leaf area nationallicence LED : light emitting diode nationallicence PIABS : photosynthetic performance index nationallicence P NA : net photosynthetic rate per unit of leaf area nationallicence P NC : net photosynthetic rate per unit of chlorophyll nationallicence R : red LEDs nationallicence W : white LEDs nationallicence Wang X. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut Xu X. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut Cui J. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/2(2015-06-01), 213-222 0300-3604 53:2<213 2015 53 11099 https://doi.org/10.1007/s11099-015-0083-8 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11099-015-0083-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wang X. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut NATIONALLICENCE 700 1- Xu X. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut NATIONALLICENCE 700 1- Cui J. College of Life Sciences, Nanjing Agricultural University, 210095, Nanjing, Jiangsu, China aut NATIONALLICENCE 773 0- Photosynthetica The Institute of Experimental Biology of the Czech Academy of Sciences 53/2(2015-06-01), 213-222 0300-3604 53:2<213 2015 53 11099