Assimilate Partitioning Within Floret Components of Contrasting Rice Spikelets Producing Qualitatively Different Types of Grains

Patel, Rajesh; Mohapatra, P. K.

doi:10.1071/pp9960085

Cited by 29 publications

(25 citation statements)

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“…1). Similar difference between dry matters partitioning of contrasting spikelets of rice panicle was reported earlier (Patel and Mohapatra 1996;Kato and Takeda 1993). Therefore, advantage accrued to the panicle of OR-1920-7 on account of larger grain number or sink size is marginalized because of the loss of individual grain weight and quality.…”

Section: Discussionsupporting

confidence: 68%

“…4), the correlations between the chemical and rates of cell division and grain growth were stronger (Table 3). We reported previously that inferior basal spikelets of rice panicle produce more ethylene compared to the dominant apical spikelets and rates of cell division and dry matter accumulation as well as the activities of enzymes for starch synthesis was slower in the former than in the latter (Patel and Mohapatra 1996;Naik and Mohapatra 2000;Mohapatra et al 2009). In the present work, it was evident that high ethylene production owing to spatial disadvantage or genetic difference restricts assimilate partitioning for the spikelets (Fig.…”

Section: Discussionmentioning

confidence: 95%

“…In contrast, spikelet development on the lower branches is impacted considerably during the early part of post anthesis period (Ishimaru et al 2003) resulting in the formation of partially filled poor quality grains (Mohapatra et al 1993). The early loss of efficiency of the basal grains to use assimilates is linked to weaker activities of the enzymes related to starch synthesis (Nakamura and Yuki 1992;Kato 1995;Patel and Mohapatra 1996;Smidansky et al 2003). Ethylene production in the flowering organs significantly affects the activities of the enzymes Mohapatra et al 2009).…”

Section: Introductionmentioning

confidence: 95%

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High ethylene production slackens seed filling in compact panicled rice cultivar

et al. 2009

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Change of plant type in rice resulting in increased compactness of the panicle, allows space for accommodation of a larger number of spikelets, but grain yield does not increase proportionately because of limitations in grain filling. The objective of this study was to evaluate potential causes of poor filling of spikelets by comparing the physiological processes that influence source and sink activities between a compact-(OR-1920-7) and a loose-panicled (Lalat) rice cultivars growing in the open field conditions in the farm of Regional Research and Technology Transfer Station, Orissa University of Agriculture and Technology, Chiplima, India during dry season of 2007. Although grain number per unit length of the branches was higher in the compact-panicled cultivar than the loose-panicled cultivar, average grain weight was lower on the primary and secondary branches at top, middle and basal positions of the panicle in the former compared to the corresponding positions of the panicle in the latter. Compared to Lalat, ethylene production rate was considerably higher in the boot of the flag leaf sheath of OR-1920-7 during the pre-anthesis period. Ethylene evolution rate correlated negatively with growth and cell division rates and starch concentration of the juvenile endosperm. Because spikelet growth was slower in OR-1920-7 than in Lalat, unused carbohydrates accumulated in the endosperm. The stomatal conductance of the flag leaf during this period was also lower in the former than that of the latter and it correlated negatively with ethylene evolution rate of the boot. It is concluded that high ethylene production slackened grain filling of compact-panicled rice cultivar OR-1920-7 because of its adverse influence on both source and sink activities.

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Section: Discussionsupporting

confidence: 68%

Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 95%

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High ethylene production slackens seed filling in compact panicled rice cultivar

et al. 2009

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“…The developing endosperm remains confined within the embryonic space (apoplasmic space; Oparka and Gates 1981a, b;Thorne 1985;Weber et al 2005) and does not have any alternate source of supply for assimilates. Endosperm cell number increases rapidly during this period and positional disadvantage on panicle axis restricting cell multiplication limits seed filling and weight in an inferior caryopsis (Patel and Mohapatra 1996). The low sink efficiency of such caryopses might have resulted in accumulation of the unused assimilates in the pericarp and endosperm (Fig.…”

Section: Discussionmentioning

confidence: 98%

Apoplasmic assimilates and grain growth of contrasting rice cultivars differing in grain dry mass and size

et al. 2010

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Apical dominance in assimilate filling impacts grain growth in basal spikelets of rice panicle. In this study, organic materials of the pericarp, apoplasmic space and endosperm of the apical and basal caryopses, and photosynthesis of the flag leaf were measured during early part of grain development in three types of rice cultivars with similar phenology, but difference in grain weight and size in the dry and wet seasons of 2006 and 2007, respectively. Photosynthetic activity of the flag leaf was consistently low in small-seeded cultivars. Rates of grain filling and cell division of endosperm and concentration of assimilates, starch, proteins and chlorophylls of the caryopsis were lower, but spikelet ethylene production and peroxidase activity were higher in a small-seeded cultivar compared to a big-seeded cultivar. Similar disparities in grain filling and other attributes were noticed for the inferior basal spikelets of the panicle compared to the superior apical spikelets, except the assimilate concentration of the pericarp and endosperm. Temporal fluctuation in assimilate concentration of the organs were similar between the cultivars. Concentration of apoplasmic assimilates mostly exhibited negative correlation with that of pericarp and endosperm. Compared to the apical spikelets, correlation was more negative for the basal spikelets. Conversely, correlation was positive between the concentration of apoplasmic assimilates and endosperm cell number and grain weight of the cultivars. Ethylene released from the spikelets at anthesis affected growth and cell division rates of endosperm and enhanced protein and chlorophyll degradation and peroxidase activity of the caryopsis. It was concluded that variation in spikelet ethylene production may be responsible for differences in size or weight of grains among rice cultivars and spikelets at different locations of the panicle. The concentration of apoplasmic assimilates could be an indicator for grain filling capacity, and ethylene regulated the concentration by affecting pericarp activity for assimilate unloading.

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“…In rice, the grain size is determined by the hull space, which is a stable varietal character (Matsushima, 1970;Peng et al, 2000;Santos et al, 2006), and grain filling is generally sink-limited (Mohapatra et al, 2004;Patel & Mohapatra, 1996), indicating that the sink size and the sink strength are more important than A. Our results indicate that in 'Primavera', matter accumulation in the grain seems to be dependent on post-flowering photosynthesis, as A was constant between 74 (FL) and 89 DAE (MA) (Figure 2a), when medium temperatures were as close as to 25 °C (Figure 5a).…”

Section: Resultsmentioning

confidence: 99%

Leaf gas exchange and yield of three upland rice cultivars

et al. 2015

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Studies of physiological parameters associated with crop performance and growth in different groups of upland rice (Oryza sativa L.) may support plant breeding programs. We evaluated the role of gas exchange rates and dry matter accumulation (DMA) as traits responsible for yields in a traditional (cv. 'Caiapó'), intermediate (cv. 'Primavera') and modern (cv. 'Maravilha') upland rice cultivars. Leaf gas exchange rates, DMA, leaf area index (LAI), harvest indexes (HI) and yield components were measured on these genotypes in the field, under sprinkler irrigation. Panicles per m 2 and DMA at flowering (FL) and heading, as well as CO 2 assimilation rates (A) were similar across these cultivars. The highest yield was found in 'Primavera', which may be explained by (i) a two-fold higher HI compared to the other cultivars, (ii) greater rates of DMA during spikelet formation and grain-filling, as well as (iii) a slow natural decrease of A in this cultivar, at the end of the season (between FL and maturation).

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Assimilate Partitioning Within Floret Components of Contrasting Rice Spikelets Producing Qualitatively Different Types of Grains

Cited by 29 publications

References 0 publications

High ethylene production slackens seed filling in compact panicled rice cultivar

High ethylene production slackens seed filling in compact panicled rice cultivar

Apoplasmic assimilates and grain growth of contrasting rice cultivars differing in grain dry mass and size

Leaf gas exchange and yield of three upland rice cultivars

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