Photosynthesis in the Pericarp of Developing Wheat Grains

Caley, C. Y.; Duffus, C. M.; Jeffcoat, B.

doi:10.1093/jxb/41.3.303

Cited by 31 publications

(30 citation statements)

References 7 publications

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“…Conservation of respired CO2 by an efficient recycling mechanism in fruit could provide a significant source of C for yield productivity (2). Cereal crops have received the greatest attention in this regard (4,9,16). For example, Kriedemann (9) studied the refixation of respired carbon dioxide in whole ears by measuring CO2 evolution of ears in a C02-free environment in the light and dark, reporting that evolution was lower in the light and suggesting that refixation was taking place.…”

mentioning

confidence: 99%

Carbon Isotope Ratios in Ear Parts of Triticale

Araus¹,

Santiveri²,

Bosch-Serra³

et al. 1992

Plant Physiol.

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Four triticale (xTriticosecale Wittmack) genotypes were grown under rainfed conditions with limited irrigation support in Lleida in northeast Spain. For each variety, samples consisting of 10 tillers with half-sterilized spikes were taken three times from anthesis to maturity. Carbon isotope ratios (513C) were then determined in water extracts from ear bracts (glumes, paleas, and lemmas), awns and flag leaves, and in powdered kernels. For the half-sterilized spikes, carbon isotope analysis was carried out separately in bracts and awns from fertile and nonfertile spikelets. The 613C in the water-soluble fraction of awns, glumes, and glumells from fruitless spikelets was significantly higher than that from fertile spikelets sampled at mid-grain filling. Differences in 613C among sterile and fertile spikelets were not significant in samples taken a few days after anthesis or at maturity. These results are in accordance with some degree of refixation by awns and ear bracts of the CO2 respired by grains during grain filling. There was progressively higher 63C from flag leaf blades to awns, glumes, and glumells. This variation in 613C along plant parts may be caused by differences in the ratio of assimilation rate to C02-diffusive conductance. Values of 613C of mature kernels were between the values at anthesis and mid-grain filling for the water-soluble fraction of flag leaves and inner bracts and were fairly similar to those of glumes and awns. Conservation of respired CO2 by an efficient recycling mechanism in fruit could provide a significant source of C for yield productivity (2). Cereal crops have received the greatest attention in this regard (4, 9, 16). For example, Kriedemann (9) studied the refixation of respired carbon dioxide in whole ears by measuring CO2 evolution of ears in a C02-free environment in the light and dark, reporting that evolution was lower in the light and suggesting that refixation was taking place. However, evidence of bracts and awns refixing the intemal CO2 released from growing grains remains to be elucidated.Carbon isotope ratios of plant tissue have been proposed as an indicator not only of water use efficiency or photosynthetic metabolism (5) but also of recycling of respired CO2 in

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mentioning

confidence: 99%

Carbon Isotope Ratios in Ear Parts of Triticale

Araus¹,

Santiveri²,

Bosch-Serra³

et al. 1992

Plant Physiol.

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“…Direct C assimilation by fruit and the subsequent availability of this photosynthate for yield productivity has generally been regarded as insignificant compared with that photosynthate supplied by leaves (5,21,24 atmospheric C02, these organs nonetheless frequently demonstrate a unique capacity for the reassimilation of internally produced C02, especially that CO2 released via mitochondrial respiration from developing ovules (4,9). Cereal crops have received the greatest attention in this regard (5,14,25), although several studies have dealt with other crops as well (2,11,15,16,23).…”

mentioning

confidence: 99%

“…Cereal crops have received the greatest attention in this regard (5,14,25), although several studies have dealt with other crops as well (2,11,15,16,23). The efficiency with which fruit are able to conserve respired C for subsequent retranslocation back to the ovule could be an important determinant of yield productivity ( 11).…”

mentioning

confidence: 99%

Evidence for Light-Dependent Recycling of Respired Carbon Dioxide by the Cotton Fruit

Wullschleger¹,

Oosterhuis²,

Hurren³

et al. 1991

Plant Physiol.

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Conservation of respired CO2 by an efficient recycling mechanism in fruit could provide a significant source of C for yield productivity. However, the extent to which such a mechanism operates in cotton (Gossypium hirsutum L.) is unknown. Therefore, a combination of CO2 exchange, stable C isotope, and chlorophyll (Chi) fluorescence techniques were used to examine the recycling of atmospheric C02, these organs nonetheless frequently demonstrate a unique capacity for the reassimilation of internally produced C02, especially that CO2 released via mitochondrial respiration from developing ovules (4, 9). Cereal crops have received the greatest attention in this regard (5, 14, 25), although several studies have dealt with other crops as well (2,11,15,16,23). The efficiency with which fruit are able to conserve respired C for subsequent retranslocation back to the ovule could be an important determinant of yield productivity ( 11).Mechanisms that govern the recycling of CO2 released via fruit respiration were investigated by Kriedemann (14) who observed a light requirement for the reassimilation process in whole ears of wheat (Triticum vulgare L.). Watson and Duffus (22) recently extended these studies by labeling caryopses of barley (Hordeum vulgare L.) with 14C02 and showed that as much as three times more 14C was retained by the caryopses after incubation in the light compared with dark-incubated caryopses. These authors concluded that the pericarp functioned as an efficient tissue for the reassimilation of 14CO2 respired by the endosperm. Similar studies have also shown the pod wall of pea (Pisum sativum L.) to contain two distinct photosynthetic layers, each capable of contributing photosynthate to seed development (2). The outer pod wall fixed CO2 from the ambient atmosphere, and the chloroplast-containing inner wall was involved in the photoassimilation of CO2 released from seed respiration. Crookston et al. (7) indicated that recycling of internally released CO2 (i.e. CO2-fixing potential) by the pod wall of Phaseolus vulgaris L. was substantial and estimated its photosynthetic capacity to be >25% that of the leaf.Kriedemann (14) proposed that under natural conditions the effective recycling ofrespired CO2 could make a significant contribution to yield by reducing respiratory C losses. We previously documented that diurnal C losses from cotton (Gossypium hirsutum L.) fruit can exceed 55% of the maximum daily C gain of these organs (24) and provided preliminary data concerning a light-dependent mechanism for CO2 reassimilation by the capsule wall (23). The efficiency by which this CO2 recycling offsets respiratory C losses could be an important aspect related to crop productivity. Therefore, the objectives of this study were to verify the light dependency of CO2 recycling by cotton fruit, document the efficiency by which this mechanism operates, and evaluate the contribution of CO2 recycling to the stable C isotope composition of the cotton fruit.

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“…Muller (1986) reported that the estimated characteristics of maximum net photosynthetic rate, gas phase diffusive conductance and photorespiration rates decreased from ear emergence to waxy ripeness. Caley et al (1990) observed that the peak photosynthetic activity at 20 d after anthesis was coinciding with the maximum chlorophyll content in the pericarp green layer. Dong (1991) reported that the canopy photosynthesis during grain filling was positively correlated with the grain yield and 1000-grain weight.…”

Section: Physiological Parametersmentioning

confidence: 91%

“…Jenner et al (1990) concluded that the rate and duration of starch and protein deposition in the grain are essentially independent events and are controlled and influenced by different factors. Caley et al (1990) suggested that starch synthase may be a rate-limiting enzyme for starch accumulation and hence the dry weight. They also concluded that termination of starch deposition might not be due to lack of starch synthase activity.…”

Section: Jiangmentioning

confidence: 99%

Studies on endogenous hormonal changes during grain development in wheat genotypes

Gutam¹

2017

Preprint

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Pot culture experiment was conducted in the Rabi seasons of 2001 and 2002 in order to study the genotypic differences in grain growth rates and endogenous hormonal contents in the developing grains. The hexaploid new plant types and extant variety and other tetraploids are taken up for the study. The data on yield and yield components show that the tetraploids had higher ear number per plant but lesser number of seeds per ear and lower seed weight per ear. The most important yield component 1000-grain yield was also possessed by hexaploids. The mean plant height was found to be higher in hexaploids over tetraploids in general, and among them DL- 1266-1 and DL-1266-2 (new plant types) recorded higher plant height. Similarly, the ear length was also higher in these new plant types. But, the tiller number/plant and ear number/plant were significantly higher in tetraploids. The new plant types (hexaploids) possessed maximum grain growth rate at 5–15 DAA. DL-1266-2 recorded highest grain growth rate 0.093 g/g/day. The photosynthetic rate values show that the hexaploids possessed higher rate than tetraploids. At 7 and 15 DAA, in general, photosynthetic rate was more when compared to 25 DAA and 35 DAA. The results showed that the endogenous hormonal contents in grains during grain development had changed in sequence. At 7 DAA, gibberellic acid (GA3) content was at maximum and at 15 DAA (rapid growth phase), indole-acetic acid (IAA) reached maximum and at 25 DAA (dough stage), ABA was at the maximum. At the 35 DAA, ABA reached all time high and GA3 the least, IAA being intermediate. Among the genotypes, hexaploids recorded higher concentrations of endogenous hormones. The total chlorophyll content in flag leaves of hexaploids was higher than tetraploids. The mean total chlorophyll had increased slightly at 20 DAA when compared to 10 DAA and it decreased at 30 DAA. It appears that the high yielding hexaploids (DL-1266-1 & Dl- 1266-2) by the virtue of possessing more 1000-grain weight and leaf area along with endogenous hormones might be responsible for higher yield as compared to tetraploids. It appears that better photosynthetic rate and better mobilization of photosynthates during grain filling stage contributes for higher yield in hexaploids.

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Photosynthesis in the Pericarp of Developing Wheat Grains

Cited by 31 publications

References 7 publications

Carbon Isotope Ratios in Ear Parts of Triticale

Carbon Isotope Ratios in Ear Parts of Triticale

Evidence for Light-Dependent Recycling of Respired Carbon Dioxide by the Cotton Fruit

Studies on endogenous hormonal changes during grain development in wheat genotypes

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