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Photoprotection as a Trait for Rice Yield Improvement: Status and Prospects.

Murchie EH, Ali A, Herman T - Rice (N Y) (2015)

Bottom Line: Photoprotective mechanisms at the chloroplast level help to avoid oxidative stress and photoinhibition, which is a light-induced reduction in photosynthetic quantum efficiency often caused by damage to photosystem II.Here we examine this evidence and identify new areas for attention.In particular we discuss how photoprotective mechanisms must be optimised at both the molecular and the canopy level in order to coordinate with efficient photosynthetic regulation and realise an increased biomass and yield in rice.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK. erik.murchie@nottingham.ac.uk.

ABSTRACT
Solar radiation is essential for photosynthesis and global crop productivity but it is also variable in space and time, frequently being limiting or in excess of plant requirements depending on season, environment and microclimate. Photoprotective mechanisms at the chloroplast level help to avoid oxidative stress and photoinhibition, which is a light-induced reduction in photosynthetic quantum efficiency often caused by damage to photosystem II. There is convincing evidence that photoinhibition has a large impact on biomass production in crops and this may be especially high in rice, which is typically exposed to high tropical light levels. Thus far there has been little attention to photoinhibition as a target for improvement of crop yield. However, we now have sufficient evidence to examine avenues for alleviation of this particular stress and the physiological and genetic basis for improvement in rice and other crops. Here we examine this evidence and identify new areas for attention. In particular we discuss how photoprotective mechanisms must be optimised at both the molecular and the canopy level in order to coordinate with efficient photosynthetic regulation and realise an increased biomass and yield in rice.

No MeSH data available.


Related in: MedlinePlus

The impact of photoinhibition on leaf photosynthetic efficiency. a: schematic depiction of how excess excitation energy is formed by the saturation of CO2 assimilation and the continued absorption of irradiance. This results in a lowering of light harvesting efficiency under low light as photoprotective processes such as NPQ begin to form and reach a maximum under high light. The proportion of excess excitation energy rises as CO2 assimilation capacity falls. b: schematic depiction of the lowering of quantum yield and maximum photosynthetic capacity according to the severity of photoinhibition (adapted from Murchie and Niyogi 2011)
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Fig1: The impact of photoinhibition on leaf photosynthetic efficiency. a: schematic depiction of how excess excitation energy is formed by the saturation of CO2 assimilation and the continued absorption of irradiance. This results in a lowering of light harvesting efficiency under low light as photoprotective processes such as NPQ begin to form and reach a maximum under high light. The proportion of excess excitation energy rises as CO2 assimilation capacity falls. b: schematic depiction of the lowering of quantum yield and maximum photosynthetic capacity according to the severity of photoinhibition (adapted from Murchie and Niyogi 2011)

Mentions: It may be difficult to separate the photosynthetic impact of photoinhibition with other metabolic perturbations caused by abiotic and biotic stresses. However it is clear that photoinhibition alone lowers ΦCO2, (quantum yield of CO2 assimilation) resulting in a sustained decline in photosynthesis (Fig. 1). Light experienced by leaves within a canopy fluctuates over space and time: canopy photosynthesis is therefore the result of large populations of chloroplasts at different states of light saturation. Thus reduction in ΦCO2 is visible during (temporary) low light episodes and can substantially limit photosynthesis (Ogren 1993; Zhu et al. 2004; Burgess et al. 2015). However, severe (chronic) photoinhibition can occur causing a decrease in both ΦCO2 and Pmax (light-saturated photosynthesis) under very high light. While it has been suggested that under certain circumstances it may occur subsequent to photosynthetic down regulation or damage possibly associated with high carbohydrate levels (Adams et al. 2013), this is not consistent with observations of rice in the field (Murchie et al. 2002).Fig. 1


Photoprotection as a Trait for Rice Yield Improvement: Status and Prospects.

Murchie EH, Ali A, Herman T - Rice (N Y) (2015)

The impact of photoinhibition on leaf photosynthetic efficiency. a: schematic depiction of how excess excitation energy is formed by the saturation of CO2 assimilation and the continued absorption of irradiance. This results in a lowering of light harvesting efficiency under low light as photoprotective processes such as NPQ begin to form and reach a maximum under high light. The proportion of excess excitation energy rises as CO2 assimilation capacity falls. b: schematic depiction of the lowering of quantum yield and maximum photosynthetic capacity according to the severity of photoinhibition (adapted from Murchie and Niyogi 2011)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4589542&req=5

Fig1: The impact of photoinhibition on leaf photosynthetic efficiency. a: schematic depiction of how excess excitation energy is formed by the saturation of CO2 assimilation and the continued absorption of irradiance. This results in a lowering of light harvesting efficiency under low light as photoprotective processes such as NPQ begin to form and reach a maximum under high light. The proportion of excess excitation energy rises as CO2 assimilation capacity falls. b: schematic depiction of the lowering of quantum yield and maximum photosynthetic capacity according to the severity of photoinhibition (adapted from Murchie and Niyogi 2011)
Mentions: It may be difficult to separate the photosynthetic impact of photoinhibition with other metabolic perturbations caused by abiotic and biotic stresses. However it is clear that photoinhibition alone lowers ΦCO2, (quantum yield of CO2 assimilation) resulting in a sustained decline in photosynthesis (Fig. 1). Light experienced by leaves within a canopy fluctuates over space and time: canopy photosynthesis is therefore the result of large populations of chloroplasts at different states of light saturation. Thus reduction in ΦCO2 is visible during (temporary) low light episodes and can substantially limit photosynthesis (Ogren 1993; Zhu et al. 2004; Burgess et al. 2015). However, severe (chronic) photoinhibition can occur causing a decrease in both ΦCO2 and Pmax (light-saturated photosynthesis) under very high light. While it has been suggested that under certain circumstances it may occur subsequent to photosynthetic down regulation or damage possibly associated with high carbohydrate levels (Adams et al. 2013), this is not consistent with observations of rice in the field (Murchie et al. 2002).Fig. 1

Bottom Line: Photoprotective mechanisms at the chloroplast level help to avoid oxidative stress and photoinhibition, which is a light-induced reduction in photosynthetic quantum efficiency often caused by damage to photosystem II.Here we examine this evidence and identify new areas for attention.In particular we discuss how photoprotective mechanisms must be optimised at both the molecular and the canopy level in order to coordinate with efficient photosynthetic regulation and realise an increased biomass and yield in rice.

View Article: PubMed Central - PubMed

Affiliation: Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK. erik.murchie@nottingham.ac.uk.

ABSTRACT
Solar radiation is essential for photosynthesis and global crop productivity but it is also variable in space and time, frequently being limiting or in excess of plant requirements depending on season, environment and microclimate. Photoprotective mechanisms at the chloroplast level help to avoid oxidative stress and photoinhibition, which is a light-induced reduction in photosynthetic quantum efficiency often caused by damage to photosystem II. There is convincing evidence that photoinhibition has a large impact on biomass production in crops and this may be especially high in rice, which is typically exposed to high tropical light levels. Thus far there has been little attention to photoinhibition as a target for improvement of crop yield. However, we now have sufficient evidence to examine avenues for alleviation of this particular stress and the physiological and genetic basis for improvement in rice and other crops. Here we examine this evidence and identify new areas for attention. In particular we discuss how photoprotective mechanisms must be optimised at both the molecular and the canopy level in order to coordinate with efficient photosynthetic regulation and realise an increased biomass and yield in rice.

No MeSH data available.


Related in: MedlinePlus