Physiological and growth characteristics of Ginkgo biloba L. exposed to open field and shade enclosure during the reproductive stage

Abstract

The current study compares responses to open field and shade enclosure condition (plastic shading nets were used to imitate a natural shading rate) to test the possible benefit of shading in terms of physiological and growth characteristics in Ginkgo biloba L. during the reproductive stage in summer. Compared with the net shade treated plants (NS-plants), the open-field plants (Oplants) contained lower chlorophyll (Chl) a ? b content and Chl a/b ratio, and exhibited a decreased ratio of Chl/ Car. Results showed that the chlorophyll fluorescence characteristics including maximum PSII photochemical efficiency (F v /F m ), potential electron transport per excited leaf cross-section (ET 0 /CS 0 ), potential electron transport per PSII reaction center (ET 0 /RC), dissipation per excited leaf cross-section (DI 0 /CS 0 ), dissipation per PSII reaction center (DI 0 /RC), and overall performance index of PSII photochemistry on absorbtion basis (PI ABS ) were altered by the net shade treatment. It was observed that the grana were illegible and difficult to distinguish by transmission electron microscopy, especially, in the cells of O-plants in which phenols were observed in the vacuole. The phenomenon of photoinhibition induced by excessive irradiance was confirmed by the abnormally high levels of the reactive oxygen species. Moreover, antioxidant enzymes activities were induced by high irradiance in the ginkgo leaves. In addition, significant differences were observed in the fresh weight and dry weight of leaves and seeds. Comparison of the variation of underlying physiological and biochemical mechanisms suggested that there was a better efficiency of ginkgo plants under artificial net shade conditions. Therefore, ginkgo plant would be best grown at 30-35 % of natural irradiance in summer months to be more profitably harvested and then meet the increasing demand of leaves and seeds.

Effect of varying NaCl doses on flavonoid production in suspension cells of Ginkgo biloba: relationship to chlorophyll fluorescence, ion homeostasis, antioxidant system and ultrastructure

“…A lower Chl a/b ratio and higher Chl a content at low NaCl levels should be beneficial to LHCII to capture high light energy, while a lower Chl a/b ratio and lower Chl a content could lead to serious photoinhibition at higher NaCl levels (C150 mM). Carotenoids can facilitate the non-radiative dissipation of excitation energy and increase antioxidant protection (Stahl and Sies 2003), in the present work, carotenoids content was reduced at C50 mM NaCl, but the Chl t/Car ratio did not decrease in the presence of different NaCl levels except at 100 and 175 mM NaCl in contrast to another report, where Chl t/Car ratio decreased in Ginkgo tree leaves under open-field condition compared with shade enclosure condition (Wang et al 2014). Furthermore, the Chl t/Car ratio in different rice genotypes had different responses to water stress (Gauthami et al 2014).…”

Effects of Multiple Planting Densities on Lignin Metabolism and Lodging Resistance of the Strip Intercropped Soybean Stem

“…Previous studies have found that under low light conditions and drought stress significantly promoted the distribution of photosynthetic products from soybean leaves to stems [77,78]. Most studies proved that plants have evolved to adapt to shade, in which plants tend to reduce the leaf weight and distribute more photosynthate to the stem to enhance the stem strength [79,80]. Our findings revealed that under the strip intercropping, the contribution rate of carbohydrate contents to stem strength increased along with shading degree increase.…”

International Biological Flora:Ginkgo biloba

“…Moreover, Ginkgo trees planted on sunny slopes generally grow better than those on shady slopes (Cao, 2007). However, Ginkgo at the reproductive stage has the best photosynthetic efficiency at 30%-35% of natural irradiance (Wang, Sun, et al, 2014).…”