Effect of Light on the Photosynthesis, Pigment Content and Stomatal Density of Sun and Shade Leaves of Vernonia Amygdalina
Keywords:Light affects the growth and development of plants by influencing the physical appearance of one leaf as well as the appearance of the whole plant. Plant photosynthesis, stomata density, and pigment contents are all influenced by light The objective of th
Light affects the growth and development of plants by influencing the physical appearance of one leaf as well as the appearance of the whole plant. Plant photosynthesis, stomata density, and pigment contents are all influenced by light The objective of this research is to determine the effect of light on the photosynthesis, pigment content and stomatal density of Sun and Shade Leaves of Vernonia amygdalina. Gas exchange was measured using Li-6400 and the data obtained was used to create a light response curve where parameters including light saturation point (LSP), light compensation point (LCP) and apparent quantum yield were estimated. Photosynthetic pigment were quantified spectrophotometrically. Moreover, the stomatal density was counted under light microscope, after making a nail polish impression of the leaf. The results discovered shows that as the light intensity increases, the gas exchange and stomatal density increases while the photosynthetic pigment of the studied plant decreases (P<0.05). In addition, LSP and LCP increases with increasing light intensity. Besides, statistically significant negative correlation (P<0.05) was achieved among stomatal density and transpiration rate thereby leading to a conclusion that sun leaves of Vernonia amygdalina contribute the highest assimilation rate to the plant than shade leaves. Yet, the higher stomatal density of sun leaves provides water saving to the plant.
 Obeta NA, & Onweluzo JC (2016) â€œEffect of debittering on phytochemicals and antioxidant composition of vernonia amygdalina and gongronema latifolium leavesâ€, International Journal of Applied and Natural Science. 5(2), 57â€“68.
 Pengelly JJ, Sirault XR, Tazoe Evans YJR, Furbank RT, & Von Caemmerer S (2010) â€œGrowth of the C4 dicot Flaveria bidentis: photosynthetic acclimation to low light through shifts in leaf anatomy and biochemistryâ€, Journal of Experimental Botany 61(14), 4109â€“4122.
 Xue W, Li XY, Zhu JT, Lin LS, & Wang YJ (2011) â€œEffects of shading on leaf morphology and response characteristics of photosynthesis in Alhagi sparsifoliaâ€, Chinese Journal of Plant Ecology 35(1), 82â€“90.
 Liu C, Guo C, Wang Y, & Ouyang F (2002) â€œEffect of light irradiation on hairy root growth and artemisinin biosynthesis of Artemisia annua Lâ€, Process Biochemistry 38(4), 581â€“585.
 Shirke PA & Pathre U, (2003 ) â€œDiurnal and Seasonal Changes in Photosynthesis and Photosystem 2 Photochemical Efficiency in Prosopis juliflora Leaves Subjected to Natural Environmental stressâ€, Photosynthetica 41(1), 83â€“89.
 Ma X, Song L, Yu W, Hu Y, Liu Y, Wu J, & Ying Y (2015) â€œGrowth, physiological, and biochemical responses of Camptotheca acuminata seedlings to different light environmentsâ€, Frontier of Plant Science 6, 321.
 Lichtenthaler K, Alexander A, Marek V, Kalina J, & Urban O (2007) â€œDifferences in pigment composition, photosynthetic rates and chlorophyll fluorescence images of sun and shade leaves of four tree speciesâ€, Plant Physiology and Biochemistry 45(8), 577â€“588.
 Marshal B & Biscoe PV (1980) â€œA Model for C 3 Leaves Describing the Dependence of Net Photosynthesis on Irradianceâ€, Journal of Experimental Botany 31(1) 29â€“39.
 Lichtenthaler HK & Buschmann C (2005) â€œChlorophylls and Carotenoids: Measurement And Characterization by UV-VIS Spectroscopyâ€, Handbook of Food Analytical Chemistry 2(2), 171â€“178, 2005.
 Xu Z & Zhou G (2008) â€œResponses of leaf stomatal density to water status and its relationship with photosynthesis in a grassâ€, Journal of Experimental Botany 59(12), 3317â€“3325.
 Lambers H, Chapin FS, & TL (2008) "Plant Physiological Ecology" Springer New York, pp.1-623.
 Sterling TM (2005) â€œTranspiration - Water Movement through Plants,â€ New Mexico, pp.1-3.
 Jifon JL & Syvertsen JP(2003) â€œModerate shade can increase net gas exchange and reduce photoinhibition in citrus leavesâ€, Tree Physiology 23(2), 119â€“127.
 Larcher L, Hara-Nishimura I, & Sternberg L (2015) â€œEffects of stomatal density and leaf water content on the (18) O enrichment of leaf water.â€, New Phytology 206(1), 141â€“151.
 Meng L, Lei-xin L, Wen-fu C, Zheng-Jin X, & Li-xia L (1999) â€œEffect of Water Stress on Stomatal Density,Length,Width and Net Photosynthetic Rate in Rice Leavesâ€, Journal of Shenyang Agricultural University 5, 1â€“5.
 GalmÃ©s J, Flexas J, SavÃ© R & Medrano H (2007) â€œWater relations and stomatal characteristics of Mediterranean plants with different growth forms and leaf habits: Responses to water stress and recoveryâ€, Plant Soil 2901(2)139â€“155.
 Camargo M & Marenco R (2011) â€œDensity, size and distribution of stomata in 35 rainforest tree species in Central Amazoniaâ€, Acta Amaz 41(2)205â€“212.
 Boccalandro HE, Rugnone ML, Moreno JE, Ploschuk EL, Serna L, Yanovsky MJ, & Casal J.J (2009) â€œPhytochrome B Enhances Photosynthesis at the Expense of Water-Use Efficiency in Arabidopsisâ€, Plant Physiology 150(2), 1083â€“1092.
 Gitz DC & Baker JT (2009) â€œMethods for Creating Stomatal Impressions Directly onto Archivable Slidesâ€, Agronomy Journal 101(1), 232.
 Adedeji O & Jewoola O (2008) â€œImportance of Leaf Epidermal Characters in the Asteraceae Familyâ€, Notulae Botanicae Horti Agrobotanici Cluj-Napoca 36(2) 7â€“16.