The Impact of CO2 on the Growth and Yield of Two Soybean Cultivars

http://www.co2science.org/articles/V24/mar/a11.php

Paper Reviewed
Soba, D., Shu, T., Runion, G.B., Prior, S.A., Fritschi, F.B., Aranjuelo, I. and Sanz-Saez, A. 2020. Effects of elevated [CO2] on photosynthesis and seed yield parameters in two soybean genotypes with contrasting water use efficiency. Environmental and Experimental Botany 178: 104154, doi.org/10.1016/j.envexpbot.2020.104154.

Soybean (Glycine max) is a key agricultural crop, the fourth most important globally in terms of seed production, and is a significant source of protein for human and livestock consumption. Consequently, it is important to understand how its growth and yield might be modified in response to future environmental change.

So what impact did this approximate 200 ppm increase in atmospheric CO2 have on these two cultivars differing in WUE?

In terms of photosynthesis, canopy measurements made during the seed filling stage revealed CO2-induced increases of 37% and 76% in the high and low WUE cultivars, respectively (Figure 1a). Aboveground biomass at this stage was also enhanced by 53% (high WUE) and 36% (low WUE). But perhaps the most significant finding was in seed yield, where elevated CO2 stimulated this key parameter by 101% in the high WUE cultivar and 65% in the low WUE cultivar (Figure 1b).

In light of the above we can expect significantly higher soybean biomass and seed yield in the future as the air's CO2 concentration rises. And these enhancements will occur with little change in seed mineral concentration, but large increases in seed mineral content.

Wheat Tolerance to Low Temperature Stress is Enhanced by Elevated CO2

http://www.co2science.org/articles/V24/mar/a13.php

Paper Reviewed
Li, H., Liu, S., Guo, J., Liu, F., Song, F. and Li, X. 2020. Effect of the transgenerational exposure to elevated CO2 on low temperature tolerance of winter wheat: Chloroplast ultrastructure and carbohydrate metabolism. Journal of Agronomy and Crop Science, DOI: 10.1111/jac.12443 .

Introducing their work, Li et al. (2020) write that although winter wheat can survive some low temperatures, it "is very sensitive to low-temperature stress during the early seedling stage before winter." And in this regard they note "ice formation in plant tissues causes dehydration, which causes damage to the cell wall and plasma membrane, hence leading to cell disruption (loss of membrane integrity and leakage of solute), loss of organelle integrity and cell regionalization," all of which actions significantly affect the stability of the cell ultrastructure. Additionally, low temperature stress reduces photosynthesis and limits energy supply to plant defenses, resulting in an overproduction of reactive oxygen species.

Against this backdrop, Li et al. wondered if elevated CO2, which is known to enhance plant photosynthesis and reduce oxidative stress, might reduce the negative impacts of low temperature stress on winter wheat. And so they set out to answer this question by focusing on temperature-induced modifications of both chloroplast ultrastructure and carbohydrate metabolism. The experiment was conducted in growth chambers under a controlled environment of ambient (400 ppm) or elevated (800 ppm) CO2 concentrations and day/night temperatures of 25°C/16°C. After 53 days, half the plants in each CO2 treatment were subjected to low temperature stress (0°C temperatures) for 14 hours. 

In summarizing their key findings, the authors report that elevated CO2 increased the number of grana lamellae and the amount of osmiophilic lipid droplets in the chloroplast, "attenuating the negative effect of low temperature on chloroplast ultrastructure." Plants grown in the 800 ppm CO2 treatment were found to have consumed more starch, which consumption helped "to generate osmo-regulating substances to prevent low-temperature damage." CO2 enrichment also increased the production of antioxidant enzymes (relative to ambient CO2 plants) to counter reactive oxygen species' damage. What is more, proline concentration, which enhances water holding capacity while decreasing the freezing point, was significantly greater in plants in the elevated CO2 treatment. Similarly, the concentration of total soluble sugars was enhanced by elevated CO2, which accumulation also "improves the ability of water retention through enhancing osmotic pressure in tissues."

Commenting on these several findings, Li et al. this conclude that exposure to elevated CO2 improves the low temperature tolerance of wheat by "maintaining stability of chloroplast ultrastructure, enhancing activities of antioxidant enzymes and concentrations of osmotic substances, and modifying the sucrose metabolism in leaves."

The Response of Sorghum to Elevated CO2, Water Stress and Nitrogen Availability      http://www.co2science.org/articles/V24/apr/a5.php

Paper Reviewed
Asadi, M. and Eshghizadeh, H.R. 2021. Response of sorghum genotypes to water deficit stress under different CO2 and nitrogen levels. Plant Physiology and Biochemistry 158: 255-264.

Sorghum is a C4 crop mainly grown in water-limited regions given its relatively high tolerance to drought. And although much is known about the response of this species to CO2 enrichment, less is known about how it may perform under a combination of growing conditions. Consequently, Asadi and Eshghizadeh (2021) evaluated the response of six sorghum genotypes under a full factorial design of factors that included atmospheric CO2 content (390 ppm or 700 ppm), water regime (normal irrigation vs water stressed) and nitrogen availability (normal soil conditions of 9.8 mg/kg N vs an added 105 mg/kg of N to the soil).

Not surprisingly, water stress negatively impacted sorghum growth while elevated CO2 and nitrogen addition enhanced it. More specifically, averaged across all treatments drought reduced shoot dry weight by 36% whereas nitrogen addition and elevated CO2 enhanced it by 22% and 29%, respectively.

Other positive findings related to elevated CO2 included (1) an enhancement of relative water content by 10% under water deficit stress, (2) improvement of the photosynthetic apparatus, and a (3) reduction in oxidative damage and stress. Consequently, in light of all their findings, Asadi and Eshghizadeh conclude "elevated CO2 alleviated the destructive effect of water limited stress on the sorghum biochemical traits."

Interactive Effects of Warming and Elevated CO2 on a Tropical Forage Species

http://www.co2science.org/articles/V24/apr/a4.php

Paper Reviewed
Alzate-Marin, A.L., Rivas, P.M.S, Galaschi-Teixeira, J.S., Bonifácio-Anacleto, F., Silva, C.C., Schuster, I., Nazareno, A.G., Giuliatti, S., da Rocha Filho, L.C., Garófalo, C.A. and Martinez, C.A. 2021. Warming and elevated CO2 induces changes in the reproductive dynamics of a tropical plant species. Science of the Total Environment 768: 144899, doi.org/10.1016/j.scitotenv.2020.144899.

In a prior study (Habermann et al., 2019) it was found that moderate warming and elevated CO2 improved the growth and biomass production of Stylosanthes capitata under adequate soil nutrient and water availability conditions. In a follow up study, Alzate-Marin et al. (2021) investigated the effects of these same two abiotic factors on plant-pollinator interactions of this economically important tropical pasture and forage species.

Commenting on these several favorable findings, Alzate-Marin et al. say that "warming and elevated CO2 increased reproductive investment by boosting flower production." And they add that "in terms of flower phenology, warming induced early flower opening [that] increased attractiveness for floral visitors and pollinators, which may be related to their preference for nectar that is warmer and with higher concentrations of sugar, which in turn may be linked to an increase in photosynthesis rate." Consequently, the researchers conclude that "the effects of elevated CO2 and warming on plant-pollinator relationships for S. capitata suggest phenological adaptation by both the plant and its pollinators to future climate change scenarios."Figure 1. Average number of Stylosanthes capitata flowers per week in the control, elevated CO2 (ECO2), elevated temperature (ET) and combined elevated CO2 and elevated temperature (ECO2 x ET) treatments. Derived from data presented in Table 1 of Alzate-Marin et al. (2021).

Large Increases in the Water Use Efficiencies of Three Tropical Forest Trees

http://www.co2science.org/articles/V24/feb/a12.php

Paper Reviewed
Rahman, M., Islam, M., Gebrekirstos, A. and Bräuning, A. 2020. Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees. Tree Physiology 40: 904-916.

Numerous scientific studies have been conducted in both laboratory and field environments to examine the impact of rising atmospheric CO2 on plant water use efficiency (WUE). In nearly all instances those studies reveal rising CO2 improves plant WUE, typically by reducing plant stomatal apertures, which reduces water lost to the air via transpiration. Consequently, at higher levels of CO2, plants tend to need less water to produce the same (or more) amount of tissue, which portends great benefits for the future of agricultural production, especially in arid and irrigated regions.

As illustrated there, iWUE increased by a very respectable 29% for T. ciliate, 29% for L. speciose, and 46% for C. tabularis over the 30-year period. With regard to the cause of these increases, statistical analyses revealed the long-term 53 ppm rise in atmospheric CO2 explained nearly all of it (86%), followed by slight influences from temperature and precipitation. Consequently, Rahman et al. conclude the "long-term iWUE trends are driven mainly by the increasing atmospheric CO2 and not by temperatures or precipitation," which conclusion they add is right in line with similar iWUE studies conducted in tropical, boreal, Mediterranean and subtropical forests, citing a number of studies in this regard.

And thus we find yet another real world example that rising atmospheric CO2 is benefitting vegetation across the globe by helping to improve plant iWUE. Amazingly, a mere 15% increase in CO2 was powerful enough to raise the intrinsic water use efficiencies of these tropical forest tree species by 29-46%. And if CO2 can do that in just three decades, imagine what it can do over a lifetime!

CO2 Enrichment Effects on Chickpea Growth and Seed Quality

http://www.co2science.org/articles/V24/apr/a3.php

Paper Reviewed
Lamichaney, A., Tewari, K., Basu, P.S., Katiyar, P.K., and Singh, N.P. 2021. Effect of elevated carbon-dioxide on plant growth, physiology, yield and seed quality of chickpea (Cicer arietinum L.) in Indo-Gangetic plains. Physiology and Molecular Biology of Plants 27: 251-263.

Working at the experimental farm of ICAR-Indian Institute of Pulses Research in Kanpur, Uttar Pradesh, India, Lamichaney et al. (2021) examined the effects of atmospheric CO2 enrichment on chickpea (Cicer arietinum, cv. JG 14). Plants were grown in the field in open-top chambers for two separate growing seasons (2017/18 and 2028/19) under either ambient (~400 ppm) or elevated (~600 ppm, maintained from 9 am to 5 pm only from plant emergence through harvest) CO2 with adequate fertilization and irrigation. Although a number of growth and physiology-related parameters were studied under these two growing conditions, the main focus of the article was on seed quality, e.g. germination rate, vigor, weight, shape, size, etc.

As expected, CO2 enrichment had a positive effect on a number of growth-related parameters. In particular, pod dry weight and total plant dry weight were stimulated by approximately 19% and 16%, respectively, in both years in the elevated CO2 treatment compared to ambient. Additionally, elevated CO2 increased both the number of pods and number of seeds per plant by 8-10% and 8-9%, respectively, leading to an overall CO2-induced increase in seed yield of 11.2% in 2017/18 and 17.6% in 2018/19.

Considering the above findings, Lamichaney et al. say their results "suggested no effect of elevated CO2 mediated changes in chickpea crop physiology on the germination and vigor of seeds produced," which finding (or rather absence thereof) "is expected to have no impact on [the] chickpea seed industry."

    Using Elevated CO2 to Enhance the Nutritive Value of Alfalfa Sprouts    http://www.co2science.org/articles/V24/apr/a1.php

Paper Reviewed
Almuhayawi, M.S., Hassan, A.H.A., Al Jaouni, S.K., Alkhalifah, D.H.M., Hozzein, W.N., Selim, S., AbdElgawad, H. and Khamis, G. 2021. Influence of elevated CO2 on nutritive value and health-promoting prospective of three genotypes of Alfalfa sprouts (Medicago Sativa). Food Chemistry 340: 128147, doi.org/10.1016/j.foodchem.2020.128147.

Writing as background for their work, Almuhayawi et al. (2021) note that humans consume alfalfa (Medicago sativa) "as sprouts, dehydrated leaves or dietary supplements in the form of tablets or powder." Sprouts, in particular, are young seedlings and they are "valuable sources of protein, minerals, vitamins, glucosinolates and phenolic compounds." Consequently, sprouts are well-recognized as a healthy food. 

Although many studies have examined the impacts of elevated CO2 on plant nutritive value, none so far have focused on alfalfa sprouts. Thus, Almuhayawi et al. set out to remedy this situation. Concentrating on three alfalfa cultivars (Giza 1, Nubaria and Ismailia 1), the team of eight Middle East scientists germinated seeds in environment-controlled growth cabinets under either ambient (400 ppm) or elevated (620 ppm) CO2. After ten days of growth the spouts were weighed and samples were taken for biochemical analysis.

And what did their work reveal?

It was little surprise that enriching the air with CO2 significantly increased the photosynthesis and growth (fresh weight) of all cultivars compared to ambient CO2 conditions. Specifically, as indicated by the data presented in Figure 1 elevated CO2 stimulated photosynthesis by 45%, 47% and 59% in Giza 1, Nubaria and Ismailia 1 cultivars, respectively, and it enhanced sprout biomass by 58% (Giza 1), 87% (Nubaria) and 108% (Ismailia 1). The CO2-induced enhancement of the photosynthetic process further aided in the accumulation of carbohydrates, proteins, fats and fibers, which parameters increased by respective three-cultivar averages of 46%, 35%, 57% and 41%. But the good news does not end here. Almuhayawi et al. further determined that elevated CO2 "boosted the levels of vitamins, phenolics, flavonoids and individual minerals and enhanced the antioxidant capacity of [the] alfalfa sprouts."

Commenting on their several findings the authors welcome and recommend elevated CO2 as "a simple and costless way with minimal challenges of application to improve the nutritive value, functionality and heal-promoting prospective of alfalfa sprouts to be a cheap but valuable source of bioactive compounds in the daily diet or used as a functional food additive to improve the nutritive value and health-promoting effects of food products."

Arctic Phytoplankton Demonstrate Resilience to Ocean Acidification

http://www.co2science.org/articles/V24/mar/a14.php

Paper Reviewed
Hoppe, C.J.M., Wolf, K.K.E., Schuback, N., Tortell, P.D. and Rost, B. 2018. Compensation of ocean acidification effects in Arctic phytoplankton assemblages. Nature Climate Change 8: 529-533.

Phytoplankton play a key role in ocean ecosystems, providing carbon and energy to higher trophic levels of the marine food web. Consequently, discerning their responses to environmental change, including so-called ocean acidification, is of high importance.

One location for which information is presently limited is the Arctic Ocean. Compared to temperate and tropical regions, the repose of phytoplankton to ocean acidification in this high latitude region has been vastly understudied. According to Hoppe et al., this is because of harsh environmental conditions and logistical difficulties. Consequently, they say it is "unclear how phytoplankton biomass accumulation in nutrient-rich and highly productive waters [in the Arctic] may be influenced by changes in the partial pressure of CO2." And so it was that this five-member scientific team set out to remedy this situation.

So what did these manipulations reveal?

Despite the wide range of experimental methods, Hoppe et al. report they found "strong evidence that Arctic primary productivity and phytoplankton community structure are largely non-responsive to ocean acidification." More specifically, they observed that only one out of the ten assemblages had a significant response to elevated pCO2. And when phytoplankton net primary production (NPP) rates were normalized for differences in chlorophyll a or particulate organic carbon concentrations, there were no significant correlations between NPP and pCO2. Consequently Hoppe et al. say these findings "suggest that coastal Arctic and subarctic phytoplankton assemblages employ efficient mechanisms to compensate for the effects of differences in CO2 availability and proton levels on NPP." Or, as they alternatively state things "coastal Arctic and subarctic primary production is largely insensitive to ocean acidification over a large range of light and temperature levels in different experimental designs."

Such "high capacity to compensate for environmental variability" is very encouraging news for those concerned about the potential effects of ocean acidification on primary producers. Clearly, out in the real world there are compensatory factors that minimize, or in this case eliminate, the negative impacts that are typically produced in the laboratory, especially in single-strain phytoplankton studies.

Soil Carbon and Nitrogen Dynamics in a Desert Ecosystem under Elevated CO2

http://www.co2science.org/articles/V24/mar/a10.php

Paper Reviewed
Koyama, A., Harlow, B. and Evans, R.D. 2019. Greater soil carbon and nitrogen in a Mojave Desert ecosystem after 10 years exposure to elevated CO2. Geoderma 355: 113915, doi.org/10.1016/j.geoderma.2019.113915.

Covering an estimated 30% of the world's land surface, arid and semi-arid ecosystems represent a significant component of the global terrestrial carbon cycle. And according to Koyama et al., they may play a more important role in the future as "these ecosystems can be more responsive to elevated CO2 than others because net primary productivity is mostly limited by water availability." Thus there is a need to investigate carbon dynamics of these regions under changing atmospheric CO2 concentrations.

Hoping to shed some light on the topic, the three scientists investigated patterns in soil organic carbon and total nitrogen in a desert ecosystem following 10 years of exposure to elevated CO2. The CO2 enrichment experiment was conducted at the Nevada Desert FACE Facility located 15 km north of Mercury, Nevada, USA. The arid site is home to six cover types, five of which were based on the dominant species (an evergreen shrub, three deciduous shrubs and a C4 grass) and the sixth representing plant interspace (i.e., no vegetation), the latter of which type held the greatest percent cover at 83.4%. During the ten years of CO2 enrichment the elevated portion of the study area was an average of 138 ppm higher than that observed in the ambient portion. At the end of the ten-year CO2 enrichment period the authors collected and analyzed soil samples for organic carbon and total nitrogen contents.

Results of the study revealed elevated CO2 stimulated soil organic carbon (SOC) contents from 9.4% to 38.0% in five of the six cover types (SOC in the C4 grass cover type declined by 9%). It also had a positive effect on total soil nitrogen (N), which varied from 6% to 42% depending once again on soil cover type.

In commenting on these observations Koyama et al. say the highest SOC and total N contents were "most evident under dominant shrubs, suggesting greater C and N input resulting from shrub growth stimulated by elevated CO2." Furthermore, they say "the greater SOC under elevated CO2 was evident in the surface as well as deeper soils, suggesting contributions of root litter and/or exudation as well as aboveground litter, [whereas] the greater total N in the top soil profile under elevated CO2 was most likely a result of both increased N2-fixation and reduced N loss." Consequently, the authors' work "suggests that, in arid ecosystems, elevated CO2 can stimulate soil organic matter formation under dominant shrubs through production of aboveground litter as well as root litter exudates." And because of the corresponding CO2-induced increase in total soil N, which "sustained net N supply," Koyama et al. conclude that "N limitation for vascular plants is less likely to occur under elevated CO2." And that strong implies arid ecosystems will gain (store) greater amounts of carbon in the future as the air's CO2 content rises, which will most certainly benefit these ecosystems.

So now that you got to see a tiny sample of the AUTHENTIC science about CO2 and plants that's all over the place..............but is being censored and/or covered up by gatekeepers of the information, who control what we get to see, let's remind everyone of what one of their favorite sources on this topic is:

https://www.youtube.com/watch?v=O2hi1cdr4jY

In case you are new here, I've been an atmospheric scientist and practicing environmentalist for 39 years..........who has studied climate science/change and agronomy for 30 years.

Can you guess what source I believe in?

This one? http://www.co2science.org/

Or this one:

https://en.wikipedia.org/wiki/Greta_Thunberg

Greta won Time magazines "person of the year" and also finished in 2nd place for the Nobel Peace Prize and earned similar awards from other gatekeepers of the information that we get. 

What did Dr. Idso and his family get for daring to tell the truth about CO2 Science?

They've been constantly targeted and labelled with things like being part of the "Dirty Dozen" (entities destroying the planet) by the gatekeepers who, when discussing the Idso's can never refute their plant science...........because its true, so instead, they do their best to smear and discredit them for showing authentic science that contradicts the message they want people to get. 

https://www.motherjones.com/environment/2009/12/dirty-dozen-climate-change-denial-11-idso-family/

So the no nothing about science and in fact is telling blatant, verifiable lies about science (but claims that she is about science and tells us to listen to the scientists) is elevated to an elite level by gate keepers of our messages........ while the real scientist(s), with several degrees, decades of studying/learning and messages that are entirely based on authentic, peer reviewed science.........are censored, shunned and smeared.

Yep, that sums up the sources  of our climate science in today's world.