Li et al. (2018) -- Elevated CO2 Improves Soybean Seed Quality

Li, Y., Yu, Z., Jin, J., Zhang, Q., 

Wang, G., Liu, C., Wu, J., 

Wang, C. and Liu, X. 

2018

"Impact of elevated CO2 

on seed quality of soybean 

at the fresh edible and 

mature stages"

Frontiers in Plant Science 9: 

Article 1413, 

doi: 10.3389/fpls.2018.01413.

NOTES:

There's growing interest 

to understand potential impacts

of rising atmospheric CO2 

on the nutritional quality 

of plants. 

Scientists have reported both 

enhancements and declines 

in various nutritional measures 

in studies examining this topic 

( see Dong et al., 2018 ):

https://elonionbloggle.blogspot.com/2019/06/dong-et-al-2018-elevated-co2-improves.html

SUMMARY:

Results from the study were mixed,

with cultivar-specific responses 

that showed increases, 

decreases, or no change, 

in the nutritional parameters 

examined. 

Li et al. say that elevated CO2 

has "both positive and negative 

effects on the nutritional quality 

of soybean seeds."

Such positive findings and 

favorable health implications 

they infer, suggest that it is 

important to evaluate 

all plant nutritional parameters 

when assessing the overall impact

of rising atmospheric CO2 

on the nutritional quality of plants. 

Too many people 

are quick to judge 

and base assessments

on changes to plant protein 

or micronutrient concentration, 

thus missing or overlooking 

important health benefits 

that elevated CO2 

promotes elsewhere, 

benefits that can outweigh 

perceived health reductions.

DETAILS:

Working with 

four soybean cultivars 

(Zhongke-maodou 1, 

Zhongke-maodou 2,

Zhongke-maodou 3 and 

Hei-maodou), 

Li et al. (2018) assessed the

effects of elevated CO2 

on the nutritional quality of 

soybean seeds at the 

fresh edible (R6) and 

mature (R8) stages 

of growth. 

They examined changes 

in crude protein, oil, 
isoflavones, free amino acids, 
fatty acids and mineral elements. 

Plants were grown in pots 

in open-top chambers at the 

Northeast Institute of Geography 

and Agroecology at the 

Chinese Academy 

of Sciences, 

Harbin, China, 

at either 390 or 550 ppm 

atmospheric CO2 

concentrations 

during the growing season 

under well-watered and 

fertilized conditions.

They note 

that elevated CO2 

reduced the 

seed protein content 

during the R8 stage 

( but not the R6 stage ), 

as well as some of 

the micronutrients 

examined 

 i.e., Zn and Fe ). 

Focusing on 

the positive findings,

the nine Chinese 

scientists report 

that soybean 

"is likely to benefit from the 

accumulation of seed fat

and isoflavone" 

under elevated CO2. 

With respect 

to the accumulation 

of seed fat, Li et al. 

write that elevated CO2 

"consistently increased 

oleic acid (18:1) concentrations 

by decreased linoleic acid (18:2) 

concentrations at R6 and R8,"

          which finding 

"indicates that elevated CO2 

improves soybean oil quality, 

with potential benefits 

for human health," 

    while also noting that 

    high levels of oleic acid 

"enhance the oxidative stability 

of soybean oil, giving it 

a longer shelf life." 

With respect to the accumulation 

of isoflavone, the scientists state 

that 

"the increase in isoflavone 

concentration of soybean 

observed in response to 

elevated CO2 suggests 

improved nutritional value 

of soybean under the scenario 

of rising CO2 levels," 

       explaining that 

"foods with high levels of isoflavone 

have been recommended by the 

U.S. Food and Drug Administration" 

            due to the 

"health-promoting effects 

of isoflavones on human vasomotor 

symptoms, the cardiovascular system,

the breast, uterus, bone, and cognition," 

        citing the works of 

      Morrison et al. (2008)

    and Clarkson et al. (2011).

REFERENCES:

Dong, J., Gruda, N., Lam, S.K., 

Li, X. and Duan, Z. 

                  2018

    "Effects of elevated CO2 

     on nutritional quality 

     of vegetables: A review."

Frontiers in Plant Science 9: 

Article 924, doi: 10.3389/fpls.2018.00924.

Morrison, M.J., Cober, E.K., 

Saleem, M.F., McLaughlin, N.B., 

Fregeau-Reid, J., Ma, B.L., 

Yan, W., and Woodrow, L. 

                 2008

    "Changes in isoflavone 

    concentration with 58 years 

    of genetic improvement 

    of short-season soybean 

    cultivars in Canada"

Crop Science 48: 2201-2208.

Clarkson, T.B., Utian, W.H., 

Barnes, S., Gold, E.B., 

Basaria, S.S., Aso, T., et al. 

                     2011

   " The role of soy isoflavones 

   in menopausal health: 

   report of The North American 

    Menopause Society

   Wulf H. Utian Translational Science 

   Symposium in Chicago, IL"

          (October 2010). 

Menopause: The Journal of the 

North American Menopause Society 18: 

732-753.