Improving the Efficiency of Photosynthesis

Zelitch, Israel

doi:10.1126/science.188.4188.626

Cited by 168 publications

(57 citation statements)

References 70 publications

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“…However, conflicting reports show a lack of IAA stimulation of photosynthesis (6,8) as well as indirect effects of IAA on source-sink relationships and transport (16). GA applications, on the other hand, have been shown to increase photochemical activity (30), photosynthetic rates (27), and respiration and translocation rates (5) in various plants. In dwarf bean (Phaseolus spp.)…”

Section: Methodsmentioning

confidence: 99%

Seasonal Changes in the Photosynthetic Rate in Apple Trees

FujII¹,

Kennedy²

1985

Plant Physiol.

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Seasonal changes in photosynthesis of apple trees (Malus domestica Borkh.) were monitored to examine the effect of source-sink interactions on photosynthesis and photorespiration. Elevated photosynthetic rates were observed during two periods of the growing season and correlated with the fruiting process. The first period of increased photosynthetic rates was during the bloom period, when spur leaves on flowering shoots exhibited up to 25% higher photosynthetic rates than vegetative spur leaves on a leaf area basis. CO2 assimilation rates were also higher in fruiting trees than nonfruiting trees during the period of rapid fruit growth from July to September. Photorespiration, dark respiration, leaf resistance, and transpiration exhibited no seasonal changes which correlated to the presence or absence of fruit. These data represent the first comprehensive examination of the effects of flowering/fruit formation on photosynthesis and photorespiration in perennial plants.Regulation of photosynthesis by fruit growth occurs in many plants, with photosynthetic promotion or reduction depending on sink demand. Other studies, however, have shown no correlation between photosynthetic rates and sink strength (cf 7). In apple (Malus domestica Borkh.), fruiting trees were shown to have reduced leaf weights (25) and leaf areas (1), but more total dry matter than nonfruiting trees (12), suggesting greater photosynthetic efficiency. In other studies, fixation of '4CO2 was usually greatest in leaves nearest the fruit, although sometimes the second nearest or even fruits further away received much of the labeled assimilates (10). Kazaryan et al. (18) also found the highest photosynthetic activity in leaves attached directly to the base of the apple pedicel and lower photosynthetic rates in leaves of nonfruiting branches of the same age. Wardlaw (29) noted that developing apple fruits always seemed to have priority demand over assimilates from adjacent leaves, whereas flowers and small or mature fruit had no effect on photosynthetic rates and attracted very little assimilates (4). From mid-June, the fruits in apple become strong sinks and may absorb nearly all assimilates from leaves on the same short shoot (spur). This suggests a pronounced fruit effect on photosynthesis during the period of intensive fruit growth (9,13 creases in apple due to the presence of fruit have not been consistent and have ranged from 40 to 400% (2,3,11,23).In general, changes in the components of net photosynthesis in fruiting trees are not well studied. In Citrus madurensis, dark respiration in fruiting and nonfruiting plants was similar (19), while Avery and Moore (3) found fruiting apple trees had lower dark respiration than nonfruiting trees, along with the lower stomatal and mesophyll resistances and increased transpiration rates. Others also recorded lower stomatal resistance (26) and higher transpiration rates (12) in fruiting apple trees.Photorespiration occurs three to five times faster than dark respiration in C3 plants and is a major ...

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Section: Methodsmentioning

confidence: 99%

Seasonal Changes in the Photosynthetic Rate in Apple Trees

FujII¹,

Kennedy²

1985

Plant Physiol.

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“…It has been suggested that crop production could be increased by improving the photosynthetic efficiency (19,28).Although in some cases there is not a clear correlation between net photosynthesis and crop yield (9, 12), some reports show a clear positive correlation between net CO2 assimilation and dry weight accumulation (7,21,29).A great variability in photosynthetic ability is found in different species as well as within different cultivars of the same species.Differences in the CO2 assimilation rate have been observed in soybean (8), maize (14), tobacco (28), alfalfa, and cotton. This variability indicates the possibility of selecting plants with higher photosynthetic efficiency.…”

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confidence: 99%

“…Differences in the CO2 assimilation rate have been observed in soybean (8), maize (14), tobacco (28), alfalfa, and cotton. This variability indicates the possibility of selecting plants with higher photosynthetic efficiency.…”

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confidence: 99%

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Selection of Nicotiana tabacum Haploids of High Photosynthetic Efficiency

Medrano

Primo‐Millo²

1985

Plant Physiol.

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Photosynthetic efficiency is an important factor for crop productivity. It has been suggested that crop production could be increased by improving the photosynthetic efficiency (19,28).Although in some cases there is not a clear correlation between net photosynthesis and crop yield (9, 12), some reports show a clear positive correlation between net CO2 assimilation and dry weight accumulation (7,21,29).A great variability in photosynthetic ability is found in different species as well as within different cultivars of the same species.Differences in the CO2 assimilation rate have been observed in soybean (8), maize (14), tobacco (28), alfalfa, and cotton. This variability indicates the possibility of selecting plants with higher photosynthetic efficiency.The rate of CO2 assimilation can be increased either by improving the conditions under which photosynthesis is performed (CO2 and 02 concentrations, temperature, illumination, and nutrition, etc.), or by breeding and selection of lines with higher photosynthetic efficiency (1, 13).Photosynthetic ability of a plant can be increased in many different ways, which are directly or indirectly related to the photosynthetic processes. For instance, selection for characteristics to improve the plant's ability to assimilate CO2 such as increased leaf surface or altered canopy structure (15, 26), delayed senescence (17), higher Chl content (1 1), or longer periods of storage of assimilates in the grain (10) has been done with varied success.

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“…There is a close correlation between plant yield and their photosynthetic rate since more than 90 % of dry matter of live plants is derived from photosynthetic CO 2 assimilation (Zelitch 1975;Joshi et al 2007). However, photosynthesis, being one of the first physiological processes to be greatly affected by temperature (Berry and Bijorkman 1980) is widely used as a tool for indicating temperature stress (Larcher 1994) and for the rapid selection of plants most suitable for different habitats (Joshi and Maikhuri 1996).…”

Section: Introductionmentioning

confidence: 99%

Temperature response of photosynthesis in different drug and fiber varieties of Cannabis sativa L.

Chandra

Lata

Khan

et al. 2011

Physiol Mol Biol Plants

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The temperature response on gas and water vapour exchange characteristics of three medicinal drug type (HP Mexican, MX and W1) and four industrial fiber type (Felinq 34, Kompolty, Zolo 11 and Zolo 15) varieties of Cannabis sativa, originally from different agro-climatic zones worldwide, were studied. Among the drug type varieties, optimum temperature for photosynthesis (T opt ) was observed in the range of 30-35°C in high potency Mexican HPM whereas, it was in the range of 25-30°C in W1. A comparatively lower value (25°C) for T opt was observed in MX. Among fiber type varieties, T opt was around 30°C in Zolo 11 and Zolo 15 whereas, it was near 25°C in Felinq 34 and Kompolty. Varieties having higher maximum photosynthesis (P N max ) had higher chlorophyll content as compared to those having lower P N max . Differences in water use efficiency (WUE) were also observed within and among the drug and fiber type plants. However, differences became less pronounced at higher temperatures. Both stomatal and mesophyll components seem to be responsible for the temperature dependence of photosynthesis (P N ) in this species, however, their magnitude varied with the variety. In general, a two fold increase in dark respiration with increase in temperature (from 20°C to 40°C) was observed in all the varieties. However, a greater increase was associated with the variety having higher rate of photosynthesis, indicating a strong association between photosynthetic and respiratory rates. The results provide a valuable indication regarding variations in temperature dependence of P N in different varieties of Cannabis sativa L.

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Improving the Efficiency of Photosynthesis

Cited by 168 publications

References 70 publications

Seasonal Changes in the Photosynthetic Rate in Apple Trees

Seasonal Changes in the Photosynthetic Rate in Apple Trees

Selection of Nicotiana tabacum Haploids of High Photosynthetic Efficiency

Temperature response of photosynthesis in different drug and fiber varieties of Cannabis sativa L.

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