Effects of Low Air Temperature and Light Intensity on Yield and Quality of Tomato at the Early Growth Stage

Abstract Harmful cyanobacterial blooms are increasing in frequency and severity, which makes their toxic secondary metabolites of microcystins (MCs) have been widely studied, especially in their distribution and influence factors in different habitats. However, the distribution of MCs on the early growth stage of harmful cyanobacteria and its influence factors and risks are still largely unknown. Thus, in the present study, two reservoirs (Lutian Reservoir and Lake Haitang) with different trophic status in China have been studied weekly from March to May in 2018, when the cyanobacteria communities were just in the early growth stage, to investigate the variation of MCs concentration and the relationships between MCs and environmental parameters. During the investigation, Lutian Reservoir and Lake Haitang were found to be mesotrophic and light eutrophic, respectively. In Lutian Reservoir, the concentration of EMCs was obviously higher than that of IMCs with a mean value of 0.323 and 0.264 μg/L, respectively. Meanwhile, the concentration of EMCs also fluctuated more sharply than that of IMCs. Congeners of IMC-YR and EMC-LR were respectively dominant in total concentrations of IMCs and EMCs. Unsurprisingly, in Lake Haitang, the concentrations of IMC and EMC were both significantly higher than that in Lutian Reservoir with a mean concentration of 0.482 and 0.472 μg/L, respectively. Differently, the concentration of MC-YR was dominant in both IMCs and EMCs, followed by MC-LR. In correlation analysis, the IMCs were significantly and positively correlated with the density and biomass of phytoplankton phyla and potential MCs-producing cyanobacteria and the parameters of water temperature (WT), nutrients and organic matters. Similar results were also observed for EMCs. While the different variation of MCs in two reservoirs might be primarily caused by the differences in WT, nutrients (especially phosphorus), organic matters and the composition of MCs-producing cyanobacteria. In addition, the coexistence of the dominant species of Pseudoanabaena sp., which can produce taste-and-odor compound of 2-methylisoborneol (2-MIB), might have significant impacts on the concentration and toxicity of MCs. Our results suggested that the risks posed by MCs at the early growth stage of cyanobacteria should also deserve our attentions, especially in mesotrophic water bodies.

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Efficacy of systemic insecticide seed treatments for protection of early-growth-stage snap beans from bean leaf beetle (Coleoptera: Chrysomelidae) foliar feeding

Crop Protection ◽

10.1016/j.cropro.2004.12.010 ◽

2005 ◽

Vol 24 (8) ◽

pp. 734-742 ◽

Cited By ~ 29

Author(s):

R.L. Koch ◽

E.C. Burkness ◽

W.D. Hutchison ◽

T.L. Rabaey

Keyword(s):

Growth Stage ◽

Leaf Beetle ◽

Early Growth ◽

Systemic Insecticide ◽

Seed Treatments ◽

Early Growth Stage ◽

Snap Beans ◽

Bean Leaf Beetle

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Growth, Development, and Chemical Constituents of Edible Ice Plant (Mesembryanthemum crystallinum L.) Produced under Combinations of Light-emitting Diode Lights

HortScience ◽

10.21273/hortsci12997-18 ◽

2018 ◽

Vol 53 (6) ◽

pp. 865-874 ◽

Cited By ~ 2

Author(s):

Thitipat Weeplian ◽

Tsair-Bor Yen ◽

Yunn-Shy Ho

Keyword(s):

Vegetative Growth ◽

Growth Stage ◽

Chemical Constituents ◽

Early Growth ◽

Mesembryanthemum Crystallinum ◽

Light Spectrum ◽

Light Emitting ◽

Early Growth Stage ◽

Light Spectra ◽

Late Growth

To investigate the effects of light treatments on the growth morphology and chemical constituents of Mesembryanthemum crystallinum L. plants, red (R), blue (B), far red (Fr), and white (W) light-emitting diodes (LEDs) were configured to provide different combinations of light spectra and photosynthetic photon flux densities (PPFDs). In Expt. 1, five light spectra of red/white (RW), red/white/far red (RWFr), red/white/high-intensity far red (RWFrD), red/blue (RB), and red/blue/far red (RBFr) were set up in two 3-layered racks with circulating hydroponic systems. In each light spectrum treatment, the distance between the LED lamps and the transplanting board was regulated to provide low PPFD and high PPFD treatments. In Expt. 2, the effect of Fr was further investigated in plants in the early and late growth stages. RWFr light was modified by covering the Fr lamps to become red/white without far red (RW−Fr) light during the early growth stage, and then removing the covers to provide the Fr spectrum red/white with far red (RW+Fr) during the later growth stage. This study suggested that high PPFD was not beneficial for promoting plant growth in any light spectrum treatment. Among light spectrum treatments at a PPFD of 215 ± 15 μmol·m−2·s−1, RW light produced higher vegetative growth. In the late growth stage, RW and RB combined with Fr light promoted reproductive growth, antioxidant activities, and secondary compounds, such as phenolic compounds, pinitol accumulation, and betacyanins. Therefore, RW (227 μmol·m−2·s−1), RW−Fr (162 μmol·m−2·s−1), and RB (162 μmol·m−2·s−1) are suggested for the early growth stage to promote vegetative growth. Then additional Fr light can be applied in addition to RW for secondary metabolite induction in the late growth stage.

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