Photosynthetic flexibility in maize exposed to salinity and shade

Sharwood, Robert E.; Sonawane, Balasaheb V.; Ghannoum, Oula

doi:10.1093/jxb/eru130

Cited by 76 publications

(76 citation statements)

References 62 publications

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“…Under nitrogen-rich conditions, N leaf is high and PEPC activity can increase to a greater extent than Rubisco, resulting in a high CO 2 concentration gradient between bundle sheath and mesophyll cells and then a high Ф value 15, 16 . However, different results were also reported in several studies 17–19 and thus the relationship between N leaf and Ф might be species-specific. In terms of C i / C a , increasing N leaf improves the allotment of nitrogen to photosynthetic enzymes and further decreases the C i / C a through stimulating the photosynthetic capacity of the plant 20, 21 .…”

Section: Introductionmentioning

confidence: 65%

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Determination of leaf carbon isotope discrimination in C4 plants under variable N and water supply

Sheng

et al. 2017

Sci Rep

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Understanding the mechanisms underlying variations in carbon isotope discrimination (Δ) in C4 plants is critical for predicting the C3/C4 ratio in C3/C4 mixed grassland. The value of Δ is determined by bundle sheath leakiness (Ф) and the ratio of intercellular to ambient CO2 concentration (C i/C a). Leaf nitrogen concentration (N leaf) is considered a driver of Δ in C4 plants. However, little is known about how N leaf affects Ф and C i/C a, and subsequently Δ. Here leaf carbon isotope composition, N leaf, Ф, and leaf gas exchange were measured in Cleistogenes squarrosa, a dominant C4 species in the Inner Mongolia grassland. Δ remained relatively stable under variable N and water supply. Higher N supply and lower water supply increased N leaf, stimulated photosynthesis and further decreased C i/C a. High N supply increased Ф, which responded weakly to water supply. N leaf exerted similar effects on C i/C a and on Ф in the field and pot experiments. Pooling all the data, N leaf explained 73% of the variation in C i/C a. Overall, both Ф and C i/C a determined Δ; however, the contribution of Ф was stronger. N leaf influenced Δ primarily though C i/C a, rather than Ф. Ф should be considered in estimating Δ of C4 endmember.

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Section: Introductionmentioning

confidence: 65%

“…More and more studies in recent years reported that Ф can be changed by environmental conditions using online measurment or model methods. For instance, high vapour pressure deficit increased Ф 32 ; shade reduced Ф 19 . It was demonstrated that the balance of C3 cycle and C4 cycle could be changed by those environmental conditions.…”

Section: Discussionmentioning

confidence: 99%

Determination of leaf carbon isotope discrimination in C4 plants under variable N and water supply

Sheng

et al. 2017

Sci Rep

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“…Total PEPC activities in leaf extracts were measured using an NADH-coupled assay as described previously (Ashton et al, 1990;Sharwood et al, 2014). Extraction was performed using the same buffer as described above.…”

Section: Pepc and Nadp-me Activitiesmentioning

confidence: 99%

The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells

et al. 2017

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In maize (Zea mays), Bundle Sheath Defective2 (BSD2) plays an essential role in Rubisco biogenesis and is required for correct bundle sheath (BS) cell differentiation. Yet, BSD2 RNA and protein levels are similar in mesophyll (M) and BS chloroplasts, although Rubisco accumulates only in BS chloroplasts. This raises the possibility of additional BSD2 roles in cell development. To test this hypothesis, transgenic lines were created that overexpress and underexpress BSD2 in both BS and M cells, driven by the cell type-specific Rubisco Small Subunit (RBCS) or Phosphoenolpyruvate Carboxylase (PEPC) promoters or the ubiquitin promoter. Genetic crosses showed that each of the transgenes could complement Rubisco deficiency and seedling lethality conferred by the bsd2 mutation. This was unexpected, as RBCS-BSD2 lines lacked BSD2 in M chloroplasts and PEPC-BSD2 lines expressed half the wild-type BSD2 level in BS chloroplasts. We conclude that BSD2 does not play a vital role in M cells and that BS BSD2 is in excess of requirements for Rubisco accumulation. BSD2 levels did affect chloroplast coverage in BS cells. In PEPC-BSD2 lines, chloroplast coverage decreased 30% to 50%, whereas lines with increased BSD2 content exhibited a 25% increase. This suggests that BSD2 has an ancillary role in BS cells related to chloroplast size. Gas exchange showed decreased photosynthetic rates in PEPC-BSD2 lines despite restored Rubisco function, correlating with reduced chloroplast coverage and pointing to CO 2 diffusion changes. Conversely, increased chloroplast coverage did not result in increased Rubisco abundance or photosynthetic rates. This suggests another limitation beyond chloroplast volume, most likely Rubisco biogenesis and/or turnover rates.

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“…and internal biotic (photosynthetic enzymes, genotype, molecular mechanism, etc.) factors (Kakani et al 2003, Arena et al 2011, Pengelly et al 2011, Benesova et al 2012, Sharwood et al 2014. The abiotic factors are the initial drivers in controlling maize photosynthetic process; water, sunlight and temperature are the three main abiotic factors.…”

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confidence: 99%

“…Lack of sunlight (solar radiation) usually causes photoinhibition (light-induced decline in photochemical activity) (Aro et al 1993, Terashima et al 1994, Sharwood et al 2014. It is reported that photosynthesis is significantly inhibited at both low and high temperatures, which usually resulted in an impaired photosynthetic apparatus and a depressed photosynthetic capacity (Janda et al 1998, Crafts-Brandner and Salvucci 2002, Naidu and Long 2004, Ben-Asher et al 2008, Suwa et al 2010.…”

mentioning

confidence: 99%

Variable photosynthetic sensitivity of maize (Zea mays L.) to sunlight and temperature during drought development process

Ji¹,

Zhou²,

Ma³

et al. 2017

PLANT SOIL ENVIRON

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The photosynthetic capacity of maize (Zea mays L.) is subject to a wide range of external abiotic factors (water, temperature, sunlight, etc.) and internal biotic (photosynthetic enzymes, genotype, molecular mechanism, etc.) factors (Kakani et al. 2003, Arena et al. 2011, Pengelly et al. 2011, Benesova et al. 2012, Sharwood et al. 2014. The abiotic factors are the initial drivers in controlling maize photosynthetic process; water, sunlight and temperature are the three main abiotic factors.It is recognised that photosynthetic inhibition (significant decline in photosynthesis) often occurs due to drought stress because of stomatal closure and damage to the photosynthetic apparatus (Lawlor and Uprety 1993, Flexas et al. 2012). Lack of sunlight (solar radiation) usually causes photoinhibition (light-induced decline in photochemical activity) (Aro et al. 1993, Terashima et al. 1994, Sharwood et al. 2014. It is reported that photosynthesis is significantly inhibited at both low and high temperatures, which usually resulted in an impaired photosynthetic apparatus and a depressed photosynthetic capacity (Janda et al. 1998, Crafts-Brandner and Salvucci 2002, Naidu and Long 2004, Ben-Asher et al. 2008, Suwa et al. 2010.Although the single effects of sunlight, temperature and water on maize photosynthesis are The complex interaction process of the abiotic factors (sunlight, air temperature and soil water) in regulating maize (Zea mays L.) photosynthesis has not been fully understood. Our field experiment explored the changed sensitivity (or role) of the abiotic factors in regulating maize photosynthesis under a drought development process. The experiment established a scenario with a long-term drought and an instantaneous cloud cover. The results revealed that long-term drought stress causes the sensitivity (or role) of sunlight and temperature exchanged in regulating maize photosynthesis. The maize photosynthesis was more sensitive to instantaneous sunlight rather than temperature in the absence of drought. However, a diminishing photosynthetic sensitivity to sunlight but an increasing photosynthetic sensitivity to temperature was observed with drought development process. The variable photosynthetic sensitivity indicated that the roles of temperature and sunlight in regulating maize photosynthesis were exchanged, so it is expected that higher photosynthetic rate could be achieved by adjusting temperature rather than sunlight after severe drought. Nevertheless, further studies are needed to provide more evidence and mechanism explanations.

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Photosynthetic flexibility in maize exposed to salinity and shade

Abstract: SummaryIn maize, salinity reduced photosynthesis by decreasing stomatal conductance. Shade downregulated PEPC more than Rubisco, leading to decreased bundle-sheath CO2 leakiness. The treatments elicited plasticity in NADP-ME/PEP-CK activity ratio.

Cited by 76 publications

References 62 publications

Determination of leaf carbon isotope discrimination in C4 plants under variable N and water supply

Determination of leaf carbon isotope discrimination in C4 plants under variable N and water supply

The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells

Variable photosynthetic sensitivity of maize (Zea mays L.) to sunlight and temperature during drought development process

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