Effects of CO2 enrichment on growth of Liquidambarstyraciflua and Pinustaeda seedlings under different irradiance levels

1984 ◽  
Vol 14 (3) ◽  
pp. 343-350 ◽  
Author(s):  
Leslie C. Tolley ◽  
B. R. Strain

Mathematical growth analysis techniques were used to assess the effects of atmospheric carbon dioxide enrichment on growth and biomass partitioning of Liquidambarstyraciflua L. (sweetgum) and Pinustaeda L. (loblolly pine) seedlings. Plants were grown from seed under high (1000 μmol•m−2•s−1) and low (250 μmol•m−2•s−1) photosynthetic photon flux density at CO2 concentrations of 350, 675, and 1000 μL•L−1 for 84 or 112–113 days. Elevated atmospheric CO2 concentration significantly increased height, leaf area, basal stem diameter, and total dry weight of sweetgum seedlings grown under high irradiance and to a lesser extent under low irradiance. Increases in dry matter accumulation were associated with early CO2 enhancement of net assimilation rate, but increases in amount of leaf surface area contributed more towards maintenance of larger size as seedlings aged. For sweetgum seedlings in particular, reduction of growth by low irradiance under normal atmospheric CO2 was compensated for by growing plants with elevated CO2. In contrast, elevated CO2 concentration produced no significant increase in growth of loblolly pine seedlings.

1984 ◽  
Vol 62 (10) ◽  
pp. 2135-2139 ◽  
Author(s):  
Leslie C. Tolley ◽  
B. R. Strain

Mathematical growth analysis techniques were used to assess the possible interactive effects of atmospheric carbon dioxide enrichment and water stress on growth and biomass partitioning of Liquidambar styraciflua L. (sweetgum) and Pinus taeda L. (loblolly pine) seedlings. Plants were grown from seed under 1000 μmol∙m−2∙s−1 photosynthetic photon flux density at CO2 concentrations of 350, 675, and 1000 μL∙L−1 for 56 days. At this time, half the seedlings in each CO2 treatment had water withheld until plant water potentials reached about −2.5 MPa in the most stressed plants, while the remaining plants were well watered. At the end of the drying cycle, stressed plants were returned to well-watered conditions for a 14-day recovery period. The greatest effects of water stress on growth were seen following the recovery period and were most severe for sweetgum seedlings grown at the lowest CO2 concentration. For sweetgum seedlings in particular, the reduction of early seedling growth following exposure to a period of drought under normal atmospheric CO2 concentration was ameliorated by growing plants under elevated CO2, primarily because of maintenance of greater net assimilation rates following a period of stress. The data presented here suggest that a doubling of atmospheric CO2 concentration would enable sweetgum seedlings to become established in drier sites which are currently dominated by loblolly pine seedlings.


2018 ◽  
Vol 98 (6) ◽  
pp. 1321-1330
Author(s):  
Jaimin S. Patel ◽  
Leora Radetsky ◽  
Mark S. Rea

Sweet basil (Ocimum basilicum L.) is primarily used for culinary purposes, but it is also used in the fragrance and medicinal industries. In the last few years, global sweet basil production has been significantly impacted by downy mildew caused by Peronospora belbahrii Thines. Nighttime exposure to red light has been shown to inhibit sporulation of P. belbahrii. The objective of this study was to determine if nighttime exposure to red light from light-emitting diodes (λmax = 625 nm) could increase plant growth (plant height and leaf size) and yield (number and weight of leaves) in basil plants. In two sets of greenhouse experiments, red light was applied at a photosynthetic photon flux density of 60 μmol m−2 s−1 during the otherwise dark night for 10 h (from 2000 to 0600). The results demonstrate that exposure to red light at night can increase the number of basil leaves per plant, plant height, leaf size (length and width), and leaf fresh and dry weight compared with plants in darkness at night. The addition of incremental red light at night has the potential to be cost-effective for fresh organic basil production in controlled environments.


Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 870 ◽  
Author(s):  
Filippos Bantis ◽  
Athanasios Koukounaras ◽  
Anastasios S. Siomos ◽  
Kalliopi Radoglou ◽  
Christodoulos Dangitsis

Watermelon is cultivated worldwide and is mainly grafted onto interspecific squash rootstocks. Light-emitting diodes (LEDs) can be implemented as light sources during indoor production of both species and their spectral quality is of great importance. The objective of the present study was to determine the optimal emission of LEDs with wide wavelength for the production of watermelon and interspecific squash seedlings in a growth chamber. Conditions were set at 22/20 °C temperature (day/night), 16 h photoperiod, and 85 ± 5 μmol m−2 s−1 photosynthetic photon flux density. Illumination was provided by fluorescent (FL, T0) lamps or four LEDs (T1, T2, T3, and T4) emitting varying wide spectra. Watermelon seedlings had greater shoot length, stem diameter, cotyledon area, shoot dry weight-to-length (DW/L) ratio, and Dickson’s quality index (DQI) under T1 and T3, while leaf area and shoot dry weight (DW) had higher values under T1. Interspecific squash seedlings had greater stem diameter, and shoot and root DW under T1 and T3, while leaf and cotyledon areas were favored under T1. In both species, T0 showed inferior development. It could be concluded that a light source with high red emission, relatively low blue emission, and a red:far-red ratio of about 3 units seems ideal for the production of high-quality watermelon (scion) and interspecific squash (rootstock) seedlings.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maral Hosseinzadeh ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Fardad Didaran

Abstract Biomass partitioning is one of the pivotal determinants of crop growth management, which is influenced by environmental cues. Light and CO2 are the main drivers of photosynthesis and biomass production in plants. In this study, the effects of CO2 levels: ambient 400 ppm (a[CO2]) and elevated to 1,000 ppm (e[CO2]) and different light intensities (75, 150, 300, 600 μmol·m−2·s−1 photosynthetic photon flux density – PPFD) were studied on the growth, yield, and biomass partitioning in chrysanthemum plants. The plants grown at higher light intensity had a higher dry weight (DW) of both the vegetative and floral organs. e[CO2] diminished the stimulating effect of more intensive light on the DW of vegetative organs, although it positively influenced inflorescence DW. The flowering time in plants grown at e[CO2] and light intensity of 600 μmol·m−2·s−1 occurred earlier than that of plants grown at a[CO2]. An increase in light intensity induced the allocation of biomass to inflorescence and e[CO2] enhanced the increasing effect of light on the partitioning of biomass toward the inflorescence. In both CO2 concentrations, the highest specific leaf area (SLA) was detected under the lowest light intensity, especially in plants grown at e[CO2]. In conclusion, elevated light intensity and CO2 direct the biomass toward inflorescence in chrysanthemum plants.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2483
Author(s):  
Alain Fortineau ◽  
Didier Combes ◽  
Céline Richard-Molard ◽  
Ela Frak ◽  
Alexandra Jullien

Plasticity of plant architecture is a promising lever to increase crop resilience to biotic and abiotic damage. Among the main drivers of its regulation are the spectral signals which occur via photomorphogenesis processes. In particular, branching, one of the yield components, is responsive to photosynthetic photon flux density (PPFD) and to red to far-red ratio (R:FR), both signals whose effects are tricky to decorrelate in the field. Here, we developed a device consisting of far-red light emitting diode (LED) rings. It can reduce the R:FR ratio to 0.14 in the vicinity of an organ without changing the PPFD in outdoor high irradiance fluctuating conditions, which is a breakthrough as LEDs have been mostly used in non-fluctuant controlled conditions at low irradiance over short periods of time. Applied at the base of rapeseed stems during the whole bolting-reproductive phase, LightCue induced an expected significant inhibitory effect on two basal targeted axillary buds and a strong unexpected stimulatory effect on the overall plant aerial architecture. It increased shoot/root ratio while not modifying the carbon balance. LightCue therefore represents a promising device for progress in the understanding of light signal regulation in the field.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tomohiro Jishi ◽  
Ryo Matsuda ◽  
Kazuhiro Fujiwara

The morphology of plants growing under combined blue- and red-light irradiation is affected by the presence or absence of time slots of blue- and red-light mono-irradiation. The purposes of this study were to investigate the morphology and growth of cos lettuce grown under light irradiation combining several durations of blue and red light simultaneously and independent mono-irradiations of blue and red light during the day, and to clarify the effects of the durations of blue-light mono-irradiation and blue-light irradiation. Young cos lettuce seedlings were grown under 24-h blue-light irradiation with a photosynthetic photon flux density (PPFD) of 110μmol m−2 s−1 (B+0R) or under 24-h blue-light irradiation with a PPFD of 100μmol m−2 s−1 supplemented with 8 (B+8R), 16 (B+16R), and 24-h (B+24R) red-light irradiation with PPFDs of 30, 15, and 10μmol m−2 s−1, respectively (Experiment 1). The daily light integral was 9.50mol m−2 in all treatments. In Experiment 1, leaf elongation was promoted as the duration of red-light irradiation decreased and the duration of blue-light mono-irradiation increased. The maximum shoot dry weight was observed under the B+8R treatment. Growth was likely promoted by the expansion of the light-receptive area caused by moderate leaf elongation without tilting. In Experiment 2, young cos lettuce seedlings were grown as for Experiment 1, but blue- and red-light irradiation intensities were reversed (R+0B, R+8B, R+16B, and R+24B). Leaf elongation was promoted by the absence of blue-light irradiation (R+0B). The leaf surface was increasingly flattened, and the shoot dry weight was enhanced, as the duration of blue-light irradiation increased. Thus, cos lettuce leaf morphology may be manipulated by adjusting each duration of blue-light mono-irradiation, red-light mono-irradiation, and blue- and red-light simultaneous irradiation, which can, in turn, promote cos lettuce growth.


HortScience ◽  
2021 ◽  
pp. 1-6
Author(s):  
Tomohiro Jishi ◽  
Ryo Matsuda ◽  
Kazuhiro Fujiwara

Cos lettuce was grown under different spectral photon flux density distribution (SPFD) change patterns with blue- and/or red light-emitting diode (LED) irradiation with a 24-hour cycle. Twelve treatments were designed with a combination of four relative SPFD (RSPFD) change patterns and three photosynthetic photon flux density (PPFD) levels. The RSPFD change patterns were as follows: BR/BR, simultaneous blue- and red-light irradiation (BR) for 24 h; R/BR, red-light monochromatic irradiation (R) for 12 h followed by 12 hours of BR; B/BR, blue-light monochromatic irradiation (B) for 12 hours followed by 12 hours of BR; and B/R, 12 hours of B followed by 12 hours of R. Each RSPFD change pattern was conducted at three daily average photosynthetic photon flux densities (PPFDave) of 50, 100, and 200 µmol·m−2·s−1. The RSPFD change patterns that included B (B/BR and B/R) resulted in elongated leaves. A low ratio of active phytochrome to total phytochrome under B was considered the reason for leaf elongation. Shoot dry weight was significantly greater under the RSPFD change patterns that included B when the PPFDave was 200 µmol·m−2·s−1. The leaf elongation caused by B would have increased the amount of light received and thereby promoted growth. However, excessive leaf elongation caused the plants to fall, and growth was not promoted under the RSPFD change patterns that included B when the PPFDave was 50 µmol·m−2·s−1. Thus, 12-hour B promoted growth under conditions in which leaf elongation leads to increases in the amount of light received.


2018 ◽  
Vol 48 (9) ◽  
Author(s):  
Felipe Ayala Tafoya ◽  
Moisés Gilberto Yáñez Juárez ◽  
Carlos Alfonso López Orona ◽  
Raymundo Medina López ◽  
Teresa de Jesús Velázquez Alcaraz ◽  
...  

ABSTRACT: Black shading nets are widely used in the protected cultivation of vegetables as a technique for controlling light and temperature, while the colored shading nets, with special optical properties to improve the use of solar radiation, appeared recently in the agricultural plastics market. Light quality transmitted by gray, aluminized, pearl, blue, red and black (control) nets with 30% shade was evaluated, as well as its effects on photosynthetic properties and fruits production of cucumber plants. Treatments (shade nets) were established under a randomized complete block design with four repetitions. The red net transmitted 23.7 and 40.3% more photosynthetic photon flux density (400 to 700nm) and red light (600 to 700nm) and the blue net transmitted 36% more blue light (400 to 500nm) in comparison with the respective transmissions of black net. All nets increased the photosynthetic responses: transpiration, stomatal conductance and CO2 assimilation, observed in plants grown under black net. Leaf greenness (41.6 SPAD units) and foliar area (90dm2) increased 22.8 and 38.9% with the red net, while the dry weight of leaf (52.5g) increased 21.9% with pearl net. Pearl, red, aluminized and blue nets showed to be viable alternatives because the production of fruit increased in 71, 48, 46 and 46%, respectively, in comparison with the conventional black net (52t ha-1).


Weed Science ◽  
1991 ◽  
Vol 39 (4) ◽  
pp. 590-594 ◽  
Author(s):  
Robert L. Zimdahl ◽  
Jingzhu Lin ◽  
Armando A. Dall'Armellina

Greenhouse and field experiments were conducted to determine effects of light, water, and chlorsulfuron on growth of Canada thistle. In the greenhouse, shoot and root dry weight, leaf area, and number of inflorescences decreased as light and water levels decreased. In the field, shoot and root dry weight, leaf area, and number of Canada thistle inflorescences were positively correlated with light intensity from 1832 to 30 μmol m−2s−1photosynthetic photon flux density (PPFD). The greatest effect of light was on inflorescence production which was eliminated at 30 μmol m−2s−1(PPFD). The combined effect of water stress and chlorsulfuron decreased root and shoot growth but did not eliminate it.


Author(s):  
L Covarelli

AbstractA field experiment was carried out in 1996 in Central Italy in order to evaluate the effects of nitrogen fertilization (0, 60, 120 kg h-1 N) of Virginia tobacco (cv. K394) in terms of net assimilation, growth and yield. Measurements of net leaf assimilation of CO2 were taken at midday under conditions of strong sunlight (Anhigh) using a portable infra-red gas analyzer and at decreasing photosynthetic photon flux density by shading the leaves with filters (An vs PPFD). For An vs PPFD measurements the Anmax value was calculated as the asymptote of the function proposed by CONNOR et al. (1). Growth was analysed by taking weekly samples to determine the fresh and dry weight and LAI (Leaf Area Index).Before topping, Anhigh (average assimilation found in lower, middle and upper leaves) rose in proportion to increased levels of N (14.7, 17.2, 20.2 μmolm-2 s-1, for 0, 60 and 120 kg ha-1 N respectively). After topping, Anhigh also grew with increased levels of N, but at a lower rate (6.8, 7.2 and 8.2μmol m-2 s-1, respectively).Similarly, for each of the three fertilization methods (N0, N60 and N120) the increase in Anmax in relation to N levels was greater before topping than afterwards (i.e. 18.7, 23.3, 26.3 μmolm-2 s-1 before topping compared to 7.5, 14.0 and 17.8 μmol m-2 s-1 after topping for each treatment respectively). The decrease of CO2 assimilation after topping was probably caused by the accumulation of soluble photo assimilates in the leaf which could have led to a feed-back control on leaf photosynthesis. In N60 and N120 treatments, which had the same leaf expansion rate of 0.14 m2 m-2 d-1 (m2 of leaf on m2 of soil per day), the rapid leaf expansion phase started about 40 days after transplanting, while it started some days later in N0 (rate of 0.11 m2 m-2 d-1). That phase ended at topping in N60 and N120, while in N0 it ended some days before topping. Biomass accumulation followed the same pattern of LAI. The rapid biomass accumulation phase was characterised by growth rates of 9, 16 and 19 g d.m. m-2 d-1, respectively for the N0, N60 and N120 treatments but did not end at topping. This confirms that assimilate accumulation occurred after topping but was not accompanied by leaf expansion. At fertilization rates of 0, 60 and 120 kg N ha-1 the yields of cured leaf tobacco were 3226, 4202 and 4839 kg ha-1 respectively.


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