Further Evidence of Oxygen Diffusion as the Determining Factor in the Relation Between Disk Thickness and Respiration of Potato Tissue

MacDonald, Ian R.

doi:10.1104/pp.43.2.274

Cited by 11 publications

(6 citation statements)

References 13 publications

(9 reference statements)

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“…Care should be taken in preparing the samples since cutting or slicing can affect the internal structure and the metabolic rate considerably (Eberhardt, 1960;MacDonald, 1968). Some measurements obtained in this way (method a) are presented in Table 3; their values are always very low.…”

Section: Measured Maintenance Respiration Ratesmentioning

confidence: 99%

The Cost of Maintenance Processes in Plant Cells

1975

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The most important maintenance processes in plants are protein turnover and active transport processes to maintain certain ion concentrations in the cells. In this paper an attempt is made to calculate the total energy cost of these processes from what is known about their specific costs and what has been observed about their rates. Because of insufficient reliable data about rates of individual maintenance processes, only approximate values can be obtained.The average turnover rate of leaf proteins may be about 100 mg protein per g proteins per day at normal temperature in leaves assimilating at moderate light intensities. This process consumes 28-53 mg glucose per g protein per day, which equals 7-13 mg glucose per g dry weight per day in leaves. It is likely that the rates of protein turnover and of C0 2 -assimilation are related. The cost of maintaining ion concentrations is estimated to be about 6-10 mg glucose per g dry weight per day in leaves. The sum of these figures is lower than is indicated by measurements of maintenance respiration. One reason for the underestimation may be that the protein turnover rates used in the calculations apply to plants with lower photosynthetic rates than the plants in which the maintenance respiration was measured. Effects of water stress and salinity, temperature and other environmental factors on the rate of maintenance processes are discussed.The consumption of assimilates for maintenance of plant cells is a significant, negative factor in plant productivity. A better understanding of the maintenance processes may give a clue how to manipulate plant characteristics or the environment to reduce the amount of assimilates consumed in these processes. It is suggested that reduction in protein turnover rates may be one such manipulation.

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Section: Measured Maintenance Respiration Ratesmentioning

confidence: 99%

The Cost of Maintenance Processes in Plant Cells

1975

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“…Such is also thought to be the case for stelar tissue freshly removed from corn roots (13). Recent evidence, however, throws doubt on this interpretation (17).…”

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confidence: 99%

“…Laties and co-workers (10, 11,, 12) considered the possibility *that release of a volatile inhibitor from slices might enhance metabolic activity, but this, too, remains problematical (17).…”

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confidence: 99%

Sodium and Potassium Absorption by Bean Stem Tissue

Rains

1969

Plant Physiol.

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Abstract. The effect of various periods of pretreatment in CaSO4 solutions (aging) on the absorption of Na and K by bean stem slices was investigated. Freshly sliced tissue absorbed Na over the entire range of concentrations studied (0.02-50 mM). Potassium absorption by fresh tissue was nil at concentrations below 0.5 mM but at higher concentrations was similar to that of Na. When tissue was aged 'by aerating slices for 20 hr in 0.5 mm CaSO4, K absorption was substantia,l over the entire range (0.01-50 mM), with evidence of a dual mechanism of absorption, whereas Na absorption was nil at concentrations below 0.2 mm. The formation of K-absorbing capacity with aging, and the loss of Na-absorbing capacity at low concentrations, were temperature-dependent and did not result from significant changes in rates of efflux of either ion. The absorption of Na by fresh tissue and K by aged tissue was sensitive to antimetabolites, with K uptake the more sensitive. Benzyladenine, an analog of kinetin, suppressed the formation of K-absorbing capability in aged tissue but did not prevent the 4loss of Naabsorbing oapacity. Possible mechanisms for this alteration in ion-specificity of transport mechanisms are discussed.

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“…In air, respiratory Qio values are higher than in buffer (Table I), and in accordance with reported Qlo values for seeds and other plant tissues under normal growth conditions (for a review, see 1 1). Limitation of respiration and growth by 02 diffusion has been described for potato discs (12) and callus (22). The inhibitory action of water on seed 02 uptake is probably due to the formation ofan unstirred aqueous boundary layer (1), where the rate of 02 diffusion is 104 times lower than in air (14).…”

Section: Discussionmentioning

confidence: 99%

Control of Seed Respiration and Growth in Vicia faba by Oxygen and Temperature: No Evidence for an Oxygen Diffusion Barrier

Visser

Dekhuijzen²,

Verkerke³

1990

Plant Physiol.

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The rate of dry matter accumulation by seeds of Vicia faba L. cv. Minica increases with temperature in the range of 16 to 26°C.The duration of dry matter accumulation decreases with temperature, resulting in a decrease of final seed dry weight. In this study we test the hypothesis that a diffusion barrier for 02, located in the seed coat, inhibits seed respiration and growth. The rate Of 02 uptake of intact seeds and of excised embryos and seed coats (separated seeds) was measured in air and buffer at 16, 20, and/or 260C at various 02 concentrations and developmental stages. Oxygen uptake rates of intact seeds in buffer were only 9 to 15% of those in air. In buffer, the respiration rate of intact seeds decreased at a PO2 below air saturation (21 kilopascals), whereas separated seeds showed a decline of 02 uptake only below 80% of air saturation. In air, embryo excision had no effect on the sensitivity of seed respiration to PO2, at both 20 and 260C. In air at 200C, separated and intact seeds showed similar rates of 02 uptake. Oxygen uptake by intact seeds, both halfway and beyond the linear growth phase, showed a temperature coefficient Q1o of 2.3 and was insensitive to p02 in the range of 80 to 100% of ambient. These results indicate that V. faba seed respiration in air is not limited by the diffusion of 02 into the seed.Both the rate and duration of seed growth are important parameters in yield formation in grain crops (13) and grain legumes (4, 6, 10). Cell division is an important process determining seed growth (5, 7, 10). One of the main environmental factors affecting these processes is temperature (4, 6, 13).The cause and mechanism of the cessation of seed growth in cereals and legumes are not known (5,6,10,13,20,23). With increasing growth temperature (16-26°C), the rate of dry matter accumulation in the seed of Vicia faba increases, but the duration of seed growth decreases. The combined effect is a lower final seed dry weight as temperature increases (4). Similar effects of temperature on seed growth have been reported for soybean (6) and wheat (13). The growth duration of Vicia embryos in vivo is similarly affected by temperature as in vitro (4,5). This has also been found for seed growth rate in soybean by Egli and Wardlaw (6). Thus, the cause of both the cessation of seed growth and the lower final seed dry weight at high temperature may be sought in processes in the seed.The relationship between growth and respiration of devel-668 oping seeds has not received much attention (10,11,20). Ohmura and Howell (15,16) were the first to suggest that 02 uptake by the cotyledons of soybean seeds during maturation may be limited by 02 diffusion through the seed coat. Recently, Sinclair (20, 21) has argued that 02 diffusion into the vascular vessels of soybean seed coats forms a potential limitation to seed respiration and growth. Gale (9) has shown that the CO2 evolution of intact soybean seeds is decreased by 02 partial pressures below ambient (<21 kPa), and suggests that the pod wall and seed coat ...

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Further Evidence of Oxygen Diffusion as the Determining Factor in the Relation Between Disk Thickness and Respiration of Potato Tissue

Cited by 11 publications

References 13 publications

The Cost of Maintenance Processes in Plant Cells

The Cost of Maintenance Processes in Plant Cells

Sodium and Potassium Absorption by Bean Stem Tissue

Control of Seed Respiration and Growth in Vicia faba by Oxygen and Temperature: No Evidence for an Oxygen Diffusion Barrier

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