scholarly journals Reaching Natural Growth: Light Quality Effects on Plant Performance in Indoor Growth Facilities

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1273
Author(s):  
Camilo Chiang ◽  
Daniel Bånkestad ◽  
Günter Hoch

To transfer experimental findings in plant research to natural ecosystems it is imperative to reach near to natural-like plant performance. Previous studies propose differences in temperature and light quantity as main sources of deviations between indoor and outdoor plant growth. With increasing implementation of light emitting diodes (LED) in plant growth facilities, light quality is yet another factor that can be optimised to prevent unnatural plant performance. We investigated the effects of different wavelength combinations in phytotrons (i.e., indoor growth chambers) on plant growth and physiology in seven different plant species from different plant functional types (herbs, grasses and trees). The results from these experiments were compared against a previous field trial with the same set of species. While different proportions of blue (B) and red (R) light were applied in the phytotrons, the mean environmental conditions (photoperiod, total radiation, red to far red ratio and day/night temperature and air humidity) from the field trial were used in the phytotrons in order to assess which wavelength combinations result in the most natural-like plant performance. Different plant traits and physiological parameters, including biomass productivity, specific leaf area (SLA), leaf pigmentation, photosynthesis under a standardised light, and the respective growing light and chlorophyll fluorescence, were measured at the end of each treatment. The exposure to different B percentages induced species-specific dose response reactions for most of the analysed parameters. Compared with intermediate B light treatments (25 and/or 35% B light), extreme R or B light enriched treatments (6% and 62% of B respectively) significantly affected the height, biomass, biomass allocation, chlorophyll content, and photosynthesis parameters, differently among species. Principal component analyses (PCA) confirmed that 6% and 62% B light quality combinations induce more extreme plant performance in most cases, indicating that light quality needs to be adjusted to mitigate unnatural plant responses under indoor conditions.

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1312
Author(s):  
Camilo Chiang ◽  
Daniel Bånkestad ◽  
Günter Hoch

Recommendations for near-natural plant growth under indoor conditions have been described without considering environmental fluctuations, which might have important consequences for researchers and plant producers when comparing results from indoor facilities with natural ecosystems or production. Previous authors proposed that differences in temperature, light quantity, and the lack of their variation are sources of deviations between indoor and outdoor experiments. Here, we investigated the effect of fluctuating light, temperature, and humidity in an indoor environment on plant performance. Seven plant species from different functional plant types were grown outdoors during summer and spring. The same species were then grown in indoor growth chambers under different scenarios of climate complexity in terms of fluctuations of temperature, air humidity, and light: (1) fixed night and day conditions, (2) daily sinusoidal changes, and (3) variable conditions tracking the climate records from the field trials. In each scenario, the average of the environmental variables was the same as in the respective field trial. Productivity-, gas exchange-, and leaf pigment-traits were measured in all plants at the end of the experiments. The plant trait responses were highly dependent on species and treatment, but general trends were observed. The variable condition yielded lower biomass compared to the fixed and sinusoidal conditions, together with a higher specific leaf area and increased chlorophyll concentrations. A principal component analysis (PCA) across all plant traits in response to climatic conditions suggested that at least a sinusoidal fluctuation is recommended for a more natural-like plant performance in indoor growth facilities. However, prevailing significant differences for several traits between field- and indoor-grown plants even under variable climates indicate that additional factors other than those controllable in standard phytotrons (e.g., wind speed and direction, leaf and soil temperature) can still significantly bias plant performance in indoor facilities.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 755
Author(s):  
Camilo Chiang ◽  
Daniel Bånkestad ◽  
Günter Hoch

Several studies have recommended the incorporation of environmental fluctuations in indoor experiments if closer-to-natural results in plant experiments are desired. Previous authors have suggested that if these fluctuations are not applied in synchrony, a stress effect could be present since plants have evolved to cope with synchronic environmental fluctuations. This study aimed to identify the effect of disparity in fluctuations of two important environmental variables, light quantity and temperature, on the growth of seven plant species from different functional plant types. A full-factorial combination of light and temperature under fixed or variable conditions was applied in phytotrons, and plant performance under these conditions was compared with a previous field trial. In all phytotron treatments, the average light and temperature conditions were the same as in the initial field trial. Productivity, leaf gas exchange, chlorophyll fluorescence, pigmentation, and other leaf traits were recorded in all species at the end of the experiments. Most plant trait responses were highly dependent on species and treatment, but some general trends were observed. Light fluctuations were mainly responsible for increases in specific leaf area (SLA) and chlorophyll a concentration, as well as for reductions in total dry weight and chlorophyll a/b ratio, independent if in combination with fluctuation or fixed temperatures. When fixed light conditions were combined with variable temperatures, the plants showed on average lower Fv/Fm values, Amax, and CO2 yield, while under variable light conditions and fixed temperatures, Fv/Fm increased compared with fully fixed or variable conditions. Although significant differences of plant traits between the field trial and all phytotron treatments were present (likely due to differences in other parameters that were not controlled in the phytotrons), our results still suggest that a synchronous variation of environmental factors lead to a more natural-like plant growth than if these factors are fixed or vary asynchronously.


Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 474-482 ◽  
Author(s):  
Jodie S. Holt

Light regulates many facets of plant growth and development through the effects of quantity of total energy and of photons, spectral quality, duration, and photoperiod. Numerous techniques and types of equipment are available for quantifying light in plant canopies. The effect of total quantity of light on weed and crop productivity has been described for many cropping systems. Recent work has focused on other aspects of light, in particular, spectral distribution of light (quality), transient light (sunflecks), and plant adaptation to changing light environments. The altered spectral quality of light in a plant canopy affects plant growth and morphology, which in turn affect competition for light. Dynamic plant response to transient light is also important to canopy photosynthesis and productivity. Plant physiological and morphological adaptation to fluctuating light is another potential factor regulating weed/crop interactions. Current cropping practices such as using smother crops and narrow row spacing exploit plant light responses to promote crop growth and suppress weed growth. A better understanding of plant responses to light quality, transient light, and fluctuating light environments will lead to a better understanding of how to manipulate the light environment in crop canopies to improve weed management.


2021 ◽  
Author(s):  
Justin M. Valliere ◽  
Haylee M. D’Agui ◽  
Kingsley W. Dixon ◽  
Paul G. Nevill ◽  
Wei San Wong ◽  
...  

Abstract Purpose Biotic and abiotic properties of soils can hinder or facilitate ecological restoration, and management practices that impact edaphic factors can strongly influence plant growth and restoration outcomes. Salvaged topsoil is an invaluable resource for mine-site restoration, and a common practice is topsoil transfer from mined areas to restoration sites. However, direct transfer is often not feasible, necessitating storage in stockpiles. We evaluated the effects of topsoil stockpiling on plant performance across diverse ecosystems impacted by mining throughout Western Australia. Methods We conducted a bioassay experiment using a widespread native Acacia species to assess how topsoil storage might impact plant growth, physiology, and nodulation by N-fixing bacteria using soils from native reference vegetation and stockpiled soils from six mine sites across Western Australia. Results Plant responses varied across mine sites, but overall plants performed better in soils collected from native vegetation, exhibiting greater biomass, more root nodules, and higher water-use efficiency compared to those grown in stockpiled soils. Soil physiochemistry showed few and minor differences between native soils and stockpiles. Conclusion Results strongly suggest observed differences in plant performance were biotic in nature. This study highlights the negative effects of topsoil storage on the biological integrity of soil across diverse ecosystems, with important implications for mine-site restoration; our results show that topsoil management can strongly influence plant performance, and stockpiled soils are likely inferior to recently disturbed topsoil for restoration purposes. We also use this study to illustrate the utility of bioassays for assessing soil quality for ecological restoration.


HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1791-1798 ◽  
Author(s):  
Kevin M. Heinz ◽  
Polly A. Harding ◽  
Maria Julissa Ek-Ramos ◽  
Heather Hernandez ◽  
Peter C. Krauter ◽  
...  

Endophytic fungi are increasingly studied for their ability to enhance plant performance in field crops, yet there are few equivalent studies in floricultural crops. Given the economic importance of these crops and pressures faced by growers to produce plants of high aesthetic quality, we surveyed the natural occurrence of foliar fungal endophytes in Knock Out® roses to identify candidate beneficial isolates. We also tested the effects of entomopathogenic fungal inocula on marigold and zinnia plant growth using different application approaches. Our survey of Knock Out® rose foliage collected from five sites within central Texas revealed at least 24 different fungal genera and 30 probable species, including some isolates providing plant stress tolerance and pathogens or antagonists of insects and nematode pests. The effects of entomopathogen inocula on plant growth varied with host plant (marigold vs. zinnia) and inoculation method (soil drench vs. seed soak). Plant responses were complex, but inoculation with Isaria fumosorosea Wize tended to have a negative effect on plant performance characteristics whereas Beauveria bassiana (Bals.-Criv.) Vuill. tended to have positive effects. When applied to marigold as a seedcoating, I. fumosorosea reduced germination, seedling fresh weight, and produced seedlings with a less compact form. By contrast, seeds inoculated with B. bassiana required less time to germinate, had higher germination rates, and increased the plant compactness. These results show that the impact of fungal entomopathogens applied as endophytes depends on the specific fungi-plant combination being examined. The effect of plant inoculation with entomopathogenic fungi within a pest management context requires further evaluation.


HortScience ◽  
2007 ◽  
Vol 42 (5) ◽  
pp. 1110-1112 ◽  
Author(s):  
James F. Cahill ◽  
Eric G. Lamb

A plant's performance depends on its ability to deal with numerous, simultaneous ecological challenges. In both natural and production systems, dominant challenges include competition for soil resources and light, herbivory, and general abiotic stress. A central goal of research is to understand how these processes interact with each other and with plant phenotype (above- and belowground) to influence overall plant performance. Complicating these efforts is the reality that plants are phenotypically plastic with the phenotypic response to one challenge potentially altering the impact of a different challenge. Furthermore, factors external to the plant (e.g., the genotypic and phenotypic composition of the surrounding plants) can also influence the consequence of various ecological pressures. We have been using Arabidopsis thaliana as a model organism to help disentangle this complicated web of ecological interactions. Competitive ability can be influenced by small genotypic changes. A plant's ability to suppress competitors is driven mainly by size-related traits and soil fertility and a plant's ability to withstand harm coming from numerous sources. The relative importance of competition is contingent not only on the match between genotype and environment, but also on the diversity of genotypes within a given population. There is a need to consider alternative effects of plant traits along with the cascading consequences of plant responses to biotic and abiotic challenges.


2012 ◽  
Vol 367 (1588) ◽  
pp. 613-629 ◽  
Author(s):  
Andrew D. B. Leakey ◽  
Jennifer A. Lau

Variation in atmospheric [CO 2 ] is a prominent feature of the environmental history over which vascular plants have evolved. Periods of falling and low [CO 2 ] in the palaeo-record appear to have created selective pressure for important adaptations in modern plants. Today, rising [CO 2 ] is a key component of anthropogenic global environmental change that will impact plants and the ecosystem goods and services they deliver. Currently, there is limited evidence that natural plant populations have evolved in response to contemporary increases in [CO 2 ] in ways that increase plant productivity or fitness, and no evidence for incidental breeding of crop varieties to achieve greater yield enhancement from rising [CO 2 ]. Evolutionary responses to elevated [CO 2 ] have been studied by applying selection in controlled environments, quantitative genetics and trait-based approaches. Findings to date suggest that adaptive changes in plant traits in response to future [CO 2 ] will not be consistently observed across species or environments and will not be large in magnitude compared with physiological and ecological responses to future [CO 2 ]. This lack of evidence for strong evolutionary effects of elevated [CO 2 ] is surprising, given the large effects of elevated [CO 2 ] on plant phenotypes. New studies under more stressful, complex environmental conditions associated with climate change may revise this view. Efforts are underway to engineer plants to: (i) overcome the limitations to photosynthesis from today's [CO 2 ] and (ii) benefit maximally from future, greater [CO 2 ]. Targets range in scale from manipulating the function of a single enzyme (e.g. Rubisco) to adding metabolic pathways from bacteria as well as engineering the structural and functional components necessary for C 4 photosynthesis into C 3 leaves. Successfully improving plant performance will depend on combining the knowledge of the evolutionary context, cellular basis and physiological integration of plant responses to varying [CO 2 ].


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 474d-474
Author(s):  
N.K. Damayanthi Ranwala ◽  
Dennis R. Decoteau

This study was conducted to evaluate the spectral properties of various colored plastic color mulches and to determine the effects of upwardly reflected light from the mulch surfaces on watermelon plant growth when differences in root zone temperatures are minimized. Two-week-old watermelon plants were grown with black mulch, red-painted mulch, SRM-Red mulch (Sonoco, Inc., Harstville, S.C.), and white mulch. Total light reflection (58 μmol·m–2·s–1 in 400–700 nm) and red: far-red (R:FR = 0.44) of reflected light were lower in black mulch and highest in white mulch (634 and 0.92, respectively). Both black mulch and white mulch had same blue:red (B:R = 0.6) while white mulch had higher B:FR (0.58) in reflected light compared to black mulch (0.26). Reflective properties of red mulches were somewhat similar, and R:FR, B:R, and B:FR were 0.8, 0.2, and 0.18, respectively. However, SRM-Red mulch had highest total light (355 μmol·m–2·s–1 in 400–700 nm) transmission through the mulch, and R:FR, B:R, and B:FR were 0.84, 0.28, and 0.23, respectively. Light transmission through the other mulches was nonsignificant. Watermelon plants grown with black mulch and red mulches had higher internode lengths compared to white mulch after 20 days. Further, plants grown under black had significant higher petiole elongation accompanied with higher dry mass partitioning to petioles, and lower partitioning to roots, stems, and leaves. There was no effects of surface mulch color on total plant dry mass or photosynthesis although plants with black had higher transpiration rate. This suggests the differential regulation of dry mass partitioning among plant parts due to mulch color. The similar plant responses with black mulch and white mulch to plants treated with FR or R light at the end of photoperiod implies the involvement of phytochrome regulation of growth due to mulch surface color.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 371
Author(s):  
Emily Medina ◽  
Su-Hwa Kim ◽  
Miriam Yun ◽  
Won-Gyu Choi

In natural ecosystems, plants are constantly exposed to changes in their surroundings as they grow, caused by a lifestyle that requires them to live where their seeds fall. Thus, plants strive to adapt and respond to changes in their exposed environment that change every moment. Heat stress that naturally occurs when plants grow in the summer or a tropical area adversely affects plants’ growth and poses a risk to plant development. When plants are subjected to heat stress, they recognize heat stress and respond using highly complex intracellular signaling systems such as reactive oxygen species (ROS). ROS was previously considered a byproduct that impairs plant growth. However, in recent studies, ROS gained attention for its function as a signaling molecule when plants respond to environmental stresses such as heat stress. In particular, ROS, produced in response to heat stress in various plant cell compartments such as mitochondria and chloroplasts, plays a crucial role as a signaling molecule that promotes plant growth and triggers subsequent downstream reactions. Therefore, this review aims to address the latest research trends and understandings, focusing on the function and role of ROS in responding and adapting plants to heat stress.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michelle Nordkvist ◽  
Maartje J. Klapwijk ◽  
La rs Edenius ◽  
Christer Björkman

AbstractMost plants are subjected to damage from multiple species of herbivores, and the combined impact on plant growth can be non-additive. Since plant response to herbivores tends to be species specific, and change with repeated damage, the outcome likely depend on the sequence and number of attacks. There is a high likelihood of non-additive effects on plant growth by damage from mammals and insects, as mammalian herbivory can alter insect herbivore damage levels, yet few studies have explored this. We report the growth response of young Scots pine trees to sequential mammal and insect herbivory, varying the sequence and number of damage events, using an ungulate-pine-sawfly system. Combined sawfly and ungulate herbivory had both additive and non-additive effects on pine growth—the growth response depended on the combination of ungulate browsing and sawfly defoliation (significant interaction effect). Repeated sawfly herbivory reduced growth (compared to single defoliation) on un-browsed trees. However, on browsed trees, depending on when sawfly defoliation was combined with browsing, trees exposed to repeated sawfly herbivory had both higher, lower and the same growth as trees exposed to a single defoliation event. We conclude that the sequence of attacks by multiple herbivores determine plant growth response.


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