Physiological and biochemical responses of green and red perilla to LED-based light.

BACKGROUND: Light-emitting diodes (LEDs) are widely used in closed-type plant production systems to improve biomass and accumulate bioactive compounds in plants. Perilla has been commonly used as herbal medicine because of its health-promoting effects. This study aimed to investigate the physiological and biochemical responses of green and red perilla under various visible-light spectra. RESULTS: Results showed that red (R) LEDs improved fresh weights of shoots and roots, plant height, internode length, node number and leaf area, as well as photosynthetic rate of green and red perilla plants compared to blue (B) LEDs and RB combined LEDs. Meanwhile, B resulted in higher stomatal conductance, transpiration rate and Fv/Fm compared to R. Supplementation of green (G) and far-red (FR) did not enhance perilla growth. Reduction or absence of B decreased leaf thickness, adaxial and abaxial epidermis, and palisade and spongy mesophyll. Total phenolic content, antioxidant capacity, rosmarinic acid content and caffeic acid content of green perilla were higher under R, R8B2 and RGB + FR, while greater values were obtained in red perilla under R. Accumulation of perillaldehyde, luteolin and apigenin presented different trends from those of rosmarinic and caffeic acids in both cultivars. CONCLUSIONS: Growth and accumulation of bioactive compounds in green perilla were greater than in red perilla under similar light quality, and R LEDs or a higher R ratio in combination treatments were suitable for cultivating high-quality green and red perilla plants in closed-type plant factories. © 2020 Society of Chemical Industry.

Effect of plant density on yield and Quality of perilla sprouts.

Growth and nutraceutical quality of perilla sprouts is strongly dependent on planting density. This study explored the influence of planting density on growth, photosynthetic parameters, antioxidant capacity, main secondary metabolites, soluble sugar and soluble protein contents of ready-to-eat sprouts. Planting at a density of 1450 plants m-2 significantly increased yield, improved the activities of antioxidant enzymes SOD and CAT, enhanced the generation of reactive oxygen species, increased the content of total chlorophyll and net photosynthetic rate, and decreased the content of MDA in perilla sprouts. The content of flavonoids, volatile oil, soluble sugar and soluble proteins was highest when the density was 1450 plants m-2 compared to other groups. The relative contents of RA and anthocyanin in perilla sprouts reached the maximum value at planting density of 1887 plants m-2.

Effects of Gellan Oligosaccharide and NaCl Stress on Growth, Photosynthetic Pigments, Mineral Composition, Antioxidant Capacity and Antimicrobial Activity in Red Perilla.

The growing market demand for plant raw materials with improved biological value promotes the extensive search for new elicitors and biostimulants. Gellan gum derivatives may enhance plant growth and development, but have never been used under stress conditions. Perilla (Perilla frutescens, Lamiaceae) is a source of valuable bioproducts for the pharmaceutical, cosmetic, and food industries. However, there is not much information on the use of biostimulators in perilla cultivation. In this work we investigated the effects of oligo-gellan and salt (100 mM NaCl) on the yield and quality of red perilla (P. frutescens var. crispa f. purpurea) leaves. Plants grown under stress showed inhibited growth, smaller biomass, their leaves contained less nitrogen, phosphorus, potassium, total polyphenol and total anthocyanins, and accumulated considerably more sodium than control plants. Treatment with oligo-gellan under non-saline conditions stimulated plant growth and the fresh weight content of the above-ground parts, enhanced the accumulation of nitrogen, potassium, magnesium and total polyphenols, and increased antioxidant activity as assessed by DPPH and ABTS assays. Oligo-gellan applied under saline conditions clearly alleviated the stress effects by limiting the loss of biomass, macronutrients, and total polyphenols. Additionally, plants pretreated with oligo-gellan and then exposed to 100 mM NaCl accumulated less sodium, produced greater amounts of photosynthetic pigments, and had greater antioxidant activity than NaCl-stressed plants. Irrespective of the experimental treatment, 50% extract effectively inhibited growth of Escherichia coli and Staphylococcus aureus. Both microorganisms were the least affected by 25% extract obtained from plants untreated with either NaCl or oligo-gellan. In conclusion, oligo-gellan promoted plant growth and enhanced the quality of red perilla leaves and efficiently alleviated the negative effects of salt stress.

Effect of weak permanent magnetic field on lipid composition and content in perilla leaves.

Composition and content of lipids were studied in leaves of red perilla plants (Perilla nankinensis [Lour.] Decne.) grown in weak permanent horizontal magnetic field (PMF) of 500 µT flux density under controlled illumination, temperature, and humidity in the phytothron chamber. Control plants were grown under similar conditions, but without PMF exposure. Exposure of perilla plants for a month to PMF retarded plant flowering as compared to control. PMF treatment increased total lipid content, including polar lipids, among them glycolipids and phospholipids. PMF did not affect content of neutral lipids. It is concluded that PMF stimulated synthesis of membrane lipids of chloroplasts, mitochondria, and cytoplasm in perilla leaves. A possible role of PMF as a factor imitating the additional light source retarding flowering of a short-day perilla plants is discussed.

Preliminary analysis on essential oil composition of Perilla L. cultivated in Lithuania.

This study represents the investigation of the essential oil of Perilla frutescens (L.) Britton, Perilla frutescens (L.) Britton var. crispa f. viridis, Perilla ocymoides L. var. bicolorlaciniata leaves collected at full flowering stage in August 2007, in Lithuania. As biogenesis and composition of essential oil depends on geographical location, environmental factors, plants with same chemotypes but growing in different conditions have different composition of major components. Plants have been cultivated in the collection of medicinal plants at Kaunas Botanical Garden of Vytautas Magnus University in Lithuania. Essential oil was analyzed using gas chromatography methods with flame ionization and mass spectrometry detectors. Thirteen constituents of essential oil, representing 96.42% of identified compounds, were indentified in the essential oil of Perilla frutescens (L.) Britton. Essential oil was ascertained to perillaketone chemotype. Principal compounds were found to be perillaketone and egomaketone. In Perilla ocymoides L. var. bicolorlaciniata aerial parts 97.70% of essential oil components were indentified with abundant amounts of perillaldehyde (72.07%) and limonene (13.15%). Essential oil contained two phenylpropanoids elemicin (1.91%) and myristicin (1.41%). In the essential oil of Perilla frutescens (L.) Britton var. crispa f. viridis 83.18% compounds were indentified. Principal compounds were found to be perillaldehyde (49.47%), limonene (11.76%), limonene oxides (9.85%) and caryophyllene oxide (7.21%). beta-Caryophyllene and perillaldehyde were the only compounds identified in all investigated perilla plants. Considering a broad diversity of Perilla L. species and chemotypes, it is important to discriminate cultivated Perilla L. species with identified chemotypes.

Practical aspects of uniform stable isotope labeling of higher plants for heteronuclear NMR-based metabolomics.

Analytical methods for probing plant metabolism are taking on new significance in the era of functional genomics, metabolomics, and systems biology. Nuclear magnetic resonance (NMR) is becoming a key technology in plant metabolomics. Stable isotope labeling of cultured cells and higher organisms has been especially promising in that it allows the use of advanced heteronuclear NMR methodologies through a combination of in vivo and in vitro measurements. This new approach provides much better resolution of the metabolite mixture signals in the multidimensional NMR spectra than does the conventional one-dimensional 1H-NMR previously used in plant metabolomics. In this chapter, we describe the practical aspects of two key NMR technologies: uniform stable labeling of plants and in vitro heteronuclear NMR.

[A study on the rotation of crops among Panax quinquefolium, Perilla frutescens and Coix lacryma-jobi].

OBJECTIVE: To provide evidence for establishing an efficient method of growing Panax quinquefolium by rotation of crops. METHOD: Four-year old P. quinquefolium was cultivated in water and soil cultures. Biological assays were conducted with the aqueous extracts of P. quinquefolius, Fructus Perillae and roots of Coix lacryma-jobi. P. quinquefolium was cultivated in the soil where purple Perilla frutesens and C. lacryma-jobi were grown previously. The effects of rotation were determined. RESULT: The stems, leaves and fibrous roots of Panax quinquefolium contained allelopathic substances. When the concentration of the allelopathic substances exceeded 1g per kg soil, P. quinquefolius could not grow. On the other hand, when the concentration of allelopathic substances fell below 0.2 g per kg soil, the rate of seedling growth was decreased by 25%. When P. quinquefolius was cultivated in the soil in which purple Perilla frutesens had previously grown, or in the soil supplemented with Fructus Perillae, the rates of seedling growth and the yield were raised by 26.8% and 11.5% tively, in comparison with the controls. CONCLUSION: Rotation of Panax quinquefolium and Perilla frutesens was shown to be a good way for the cultivation of the former. During the growing process, application of Fructus Perillae to the soil could further enhance the growth and of Panax quinquefolium.

Comparison of peptides in the phloem sap of flowering and non-flowering Perilla and lupine plants using microbore HPLC followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Physiological evidence indicates that flower formation is hormonally controlled. The floral stimulus, or florigen, is formed in the leaves as a response to an inductive photoperiod and translocated through the phloem to the apical meristem. However, because of difficulties in obtaining and analyzing phloem sap and the lack of a bioassay, the chemical nature of this stimulus is one of the major unsolved problems in plant biology. A combination of microbore high-performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to compare the contents of the phloem sap from flowering and non-flowering plants. Instead of using one- or two-dimensional gel electrophoresis, microbore HPLC separations allowed us to detect proteins/peptides that were very small and present at very low levels. We detected more than 100 components in the phloem sap of Perilla ocymoides L. and Lupinus albusL. Sequences for 16 peptides in a mass range from 1 to 9 kDa were obtained. Two of these could be identified, 11 showed similarity to known or deduced protein sequences, and three showed no similarity to any known protein or translated gene sequence. Four of these peptides were specific to, modified, or increased in plants that were flowering, indicating their possible role in flower induction. The sequences of these peptides showed similarities to two purine permeases, a protein with similarity to protein kinases, and a protein with no similarities to any known protein.