The Effect of Photoperiod on Necrosis Development, Photosynthetic Efficiency and ‘Green Islands’ Formation in Brassica juncea Infected with Alternaria brassicicola

International Journal of Molecular Sciences

卷:22

Mirosław Sobczak¹  Andrzej Kiejstut Kononowicz²  Jakub Oliwa³  Andrzej Skoczowski³  Magdalena Gapińska⁴  Sylwia Michlewska⁴  Iwona Ciereszko⁵  Violetta Katarzyna Macioszek⁵ 

[1] Department of Botany, Institute of Biology, Warsaw University of Life Sciences—SGGW, 02-787 Warsaw, Poland;

[2] Department of Plant Ecophysiology, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland;

[3] Institute of Biology, Pedagogical University of Krakow, 30-084 Krakow, Poland;

[4] Laboratory of Microscopy Imaging and Specialized Biological Techniques, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland;

[5] Laboratory of Plant Physiology, Department of Biology and Plant Ecology, Faculty of Biology, University of Bialystok, 15-245 Bialystok, Poland;

关键词: biotic stress;    continuous light;    chlorophyll a fluorescence;    chloroplast ultrastructure;    carotenoids;    ‘green islands’;   

DOI  :  10.3390/ijms22168435

来源: DOAJ

【 摘 要 】

The main goal of growing plants under various photoperiods is to optimize photosynthesis for using the effect of day length that often acts on plants in combination with biotic and/or abiotic stresses. In this study, Brassica juncea plants were grown under four different day-length regimes, namely., 8 h day/16 h night, 12 h day/12 h night, 16 h day/8 h night, and continuous light, and were infected with a necrotrophic fungus Alternaria brassicicola. The development of necroses on B. juncea leaves was strongly influenced by leaf position and day length. The largest necroses were formed on plants grown under a 16 h day/8 h night photoperiod at 72 h post-inoculation (hpi). The implemented day-length regimes had a great impact on leaf morphology in response to A. brassicicola infection. They also influenced the chlorophyll and carotenoid contents and photosynthesis efficiency. Both the 1st (the oldest) and 3rd infected leaves showed significantly higher minimal fluorescence (F₀) compared to the control leaves. Significantly lower values of other investigated chlorophyll a fluorescence parameters, e.g., maximum quantum yield of photosystem II (F_v/F_m) and non-photochemical quenching (NPQ), were observed in both infected leaves compared to the control, especially at 72 hpi. The oldest infected leaf, of approximately 30% of the B. juncea plants, grown under long-day and continuous light conditions showed a ‘green island’ phenotype in the form of a green ring surrounding an area of necrosis at 48 hpi. This phenomenon was also reflected in changes in the chloroplast’s ultrastructure and accelerated senescence (yellowing) in the form of expanding chlorosis. Further research should investigate the mechanism and physiological aspects of ‘green islands’ formation in this pathosystem.

【 授权许可】

Unknown