Light Shock Stress after Outdoor Sunlight Exposure in Seedlings of Picea abies (L.) Karst. and Pinus sylvestris L. Pre-Cultivated under LEDs—Possible Mitigation Treatments and Their Energy Consumption

Natural Bioactive Substances in Fruits of Aronia melanocarpa (Michx.) Elliott Exposed to Combined Light-Type, Chitosan Oligosaccharide, and Spent Mushroom Residue Treatments

Greenhouse culture is a practical approach to obtain non-wood forest products from berry fruit at a higher efficacy than resource silviculture in natural understory. In this study, three-year old black chokeberry (Aronia melanocarpa (Michx.) Elliott 1821) seedlings were transplanted to a greenhouse where sunlight was complemented by red- (69.4% red, 30.2% green, 0.4% blue) and blue-color (15.3% red, 64.9% green, 19.8% blue) light-emitting diode (LED) illuminations. Half of the planting soils were amended by spent mushroom residue (SMR) (not amendment as the control) and half the seedlings were sprayed by chitosan oligosaccharide (CO) on leaves. All treatments can increase seedling height, but only blue light reinforces the basal diameter growth. Compared to sunlight, exposure to blue light can promote leaf nitrogen and phosphorus concentrations, superoxide dismutase activity, and fruit proanthocyanidin content. The combination with CO addition will further increase chlorophyl a content, acid phosphatase activity, and total phenolics in fruit. SMR amended can induce the steady state uptake of nutrients but failed to impact fruit quality. Overall, we recommend the combination of blue light LED illumination plus CO addition to culture black chokeberry for the purpose to gain natural bioactive compounds.

UV-B-induced molecular mechanisms of stress physiology responses in the major northern Chinese conifer Pinus tabuliformis Carr

During their lifetimes, plants are exposed to different abiotic stress factors eliciting various physiological responses and triggering important defense processes. For UV-B radiation responses in forest trees, the genetics and molecular regulation remain to be elucidated. Here, we exposed Pinus tabuliformis Carr., a major conifer from northern China, to short-term high-intensity UV-B and employed a systems biology approach to characterize the early physiological processes and the hierarchical gene regulation, which revealed a temporal transition from primary to secondary metabolism, the buildup of enhanced antioxidant capacity and stress-signaling activation. Our findings showed that photosynthesis and biosynthesis of photosynthetic pigments were inhibited, while flavonoids and their related derivates biosynthesis, as well as glutathione and glutathione S-transferase mediated antioxidant processes, were enhanced. Likewise, stress-related phytohormones (jasmonic acid, salicylic acid and ethylene), kinase and reactive oxygen species signal transduction pathways were activated. Biological processes regulated by auxin and karrikin were, for the first time, found to be involved in plant defense against UV-B by promoting the biosynthesis of flavonoids and the improvement of antioxidant capacity in our research system. Our work evaluated the physiological and transcriptome perturbations in a conifer's response to UV-B, and generally, highlighted the necessity of a systems biology approach in addressing plant stress biology.