The crosstalk of far-red energy and signaling defines the regulation of photosynthesis, growth, and flowering in tomatoes.

This study investigated the effect of light intensity and signaling on the regulation of far-red (FR)-induced alteration in photosynthesis. The low (LL: 440 µmol m-2 s-1) and high (HL: 1135 µmol m-2 s-1) intensity of white light with or without FR (LLFR: 545 µmol m-2 s-1 including 115 µmol m-2 s-1; HLFR: 1254 µmol m-2 s-1 + 140 µmol m-2 s-1) was applied on the tomato cultivar (Solanum Lycopersicon cv. Moneymaker) and mutants of phytochrome A (phyA) and phytochrome B (phyB1, and phyB2). Both light intensity and FR affected plant morphological traits, leaf biomass, and flowering time. Irrespective of genotype, flowering was delayed by LLFR and accelerated by HLFR compared to the corresponding light intensity without FR. In LLFR, a reduced energy flux through the electron transfer chain along with a reduced energy dissipation per reaction center improved the maximum quantum yield of PSII, irrespective of genotype. HLFR increased net photosynthesis and gas exchange properties in a genotype-dependent manner. FR-dependent regulation of hormones was affected by light signaling. It appeared that PHYB affected the levels of abscisic acid and salicylic acid while PHYA took part in the regulation of CK in FR-exposed plants. Overall, light intensity and signaling of FR influenced plants' photosynthesis and growth by altering electron transport, gas exchange, and changes in the level of endogenous hormones.

Identification of variety-specific metabolites of basil by high performance thin layer chromatography-assisted metabolic profiling techniques.

The technological advances of analytical instrumentation and techniques has laid the ground for the rapid expansion of metabolomics or in a wider sense, untargeted analysis applied to life sciences themes. However, the objective of identifying all existing metabolites within organisms remains a daunting challenge. All analytical techniques exhibit varying degrees of sensitivity and versatility for the detection of metabolites and none of the existing analytical platforms can be expected to be ideal for exhaustive chemical profiling. Planar liquid chromatography, and in particular, high performance thin layer chromatography (HPTLC), has been used for chemical profiling of natural products in conjunction with metabolomics. HPTLC has specific advantages which include its ability to generate reliable chemical fingerprinting data and facilitate preparative work for metabolite isolation during later stages of metabolomics analysis. In this study, we investigated the chemical profiles of four commercially available basil cultivars, namely Dolly, Emily, Keira, and Rosie. We used HPTLC as the primary analytical tool for the separation of basil cultivars based on detected metabolites, and then compared the results with those obtained with other analytical platforms. We identified the characteristic marker compounds of each basil cultivar from the HPTLC plates and validated their potential using LC-MS and GC-MS analyses as a metabolomics tool. Firstly, we compared the HPTLC data of the four cultivars, obtained with two systems that used silica gel 60 and two mobile phases composed of toluene-EtOAc (8:2, v/v) and EtOAc-formic acid-acetic acid-water (100:11:11:27, v/v), with 1H NMR data to evaluate their separation power. Despite providing lower resolution and detecting fewer compounds, the HPTLC separation power was comparable, and in some cases even better than that of 1H NMR. Additionally, we investigated the potential of HPTLC as a tool for chemical fingerprinting and demonstrated its suitability for preparative purposes that are essential for identifying metabolites in mixture analysis. Metabolites were easily isolated from sample mixtures, and identified with the assistance of GC-MS, LC-MS, and TLC-densitometry.. Several marker compounds were thus identified, including 2,4 di-tertbutylphenol, palmitic acid, hexadecanamide, 9-octadecenamide, squalene, hentriacontane, methyl 3-(3,5-ditert­butyl­4-hydroxyphenyl)propanoic acid, sagerinic acid, and cyanidin-3-O-sophoroside.

Vertical farming.

Ji et al. introduce vertical farming, a production-scale crop-growth system within an enclosed structure that maximizes space-use efficiency by growing plants vertically and precisely controls the plant environment.

Far-red radiation stimulates dry mass partitioning to fruits by increasing fruit sink strength in tomato.

Far-red (FR) light promotes fruit growth by increasing dry mass partitioning to fruits, but the mechanism behind this is unknown. We hypothesise that it is due to an increased fruit sink strength as FR radiation enhances sugar transportation and metabolism. Tomato plants were grown with or without 50-80 µmol m-2  s-1 of FR radiation added to a common background 150-170 µmol m-2  s-1 red + blue light-emitting diode lighting. Potential fruit growth, achieved by pruning each truss to one remaining fruit, was measured to quantify fruit sink strength. Model simulation was conducted to test whether the measured fruit sink strength quantitatively explained the FR effect on dry mass partitioning. Starch, sucrose, fructose and glucose content were measured. Expression levels of key genes involved in sugar transportation and metabolism were determined. FR radiation increased fruit sink strength by 38%, which, in model simulation, led to an increased dry mass partitioned to fruits that quantitatively agreed very well with measured partitioning. FR radiation increased fruit sugar concentration and upregulated the expression of genes associated with both sugar transportation and metabolism. This is the first study to demonstrate that FR radiation stimulates dry mass partitioning to fruits mainly by increasing fruit sink strength via simultaneous upregulation of sugar transportation and metabolism.

Dissecting the Genotypic Variation of Growth Responses to Far-Red Radiation in Tomato.

The recent development of light-emitting diodes (LEDs) and their application in modern horticulture stimulated studies demonstrating that additional far-red (FR) radiation (700-800 nm) increases plant dry mass. This effect of FR has been explained by improved photosynthesis and/or plant architecture. However, the genotypic variation in this response is largely unknown. Here, we aim to explore and explain the genotypic variation in growth responses to additional FR. We expected the genotypic variation in the responses of plant dry mass to additional FR. Further, we hypothesized that a significant improvement of both net assimilation rate (NAR) and leaf area ratio (LAR) is responsible for a strong dry mass increase under additional FR, while some genotypes respond only marginally or even negatively in NAR or LAR under FR, thus resulting in a weak FR effect on plant dry mass. To test these hypotheses, we grew 33 different tomato genotypes for 21 days with 0, 25, or 100 µmol m-2 s-1 of FR added to a common white + red LED background lighting of 150 µmol m-2 s-1. Genotypes responded similarly with respect to plant height, stem dry mass, and shoot:root ratio; i.e., they all increased with increasing FR. However, the response of total plant dry mass varied among genotypes. We categorized the genotypes into three groups (strongly, moderately, and weakly responding groups) based on their relative response in total plant dry mass to FR. Growth component analysis revealed that the strongly responding genotypes increased strongly in NAR rather than LAR. The weakly responding genotypes, however, showed a substantial increase in LAR but not NAR. The increase in LAR was due to the increase in specific leaf area. Leaf mass fraction, which is the other component of LAR, decreased with FR and did not differ between groups. In conclusion, tomato genotypes that increased strongly in NAR in response to FR were able to achieve a more substantial increase in dry mass than did other genotypes. This is the first study to explain the differences in growth responses of a large number of tomato genotypes toward FR in their light environment.