Effect of high temperature on photosynthesis in potatoes.
Vander Zaag, 1988: The response of potato (Solanum spp.) to photoperiod and light intensity under high temperatures.
02 inhibition of photosynthesis in potatoes and the effect of ..
Figure 14.28. In heat tolerant plants, growth at warm temperatures results in acclimation of photosynthesis. Adjustments in membrane composition, protein synthesis, and metabolic regulation alleviate some of the effects of high temperature. Acclimation is mediated, in part, by an increase in expression of heat shock proteins. Based on Sage and Kubien (2007) and Yamori et al. (2014).
For many years, the inhibition of gross photosynthesis was thought to occur at temperatures too low to be explained by the thermal deactivation of photosynthetic enzymes. Experiments comparing the thermal response of many steps in the photosynthetic apparatus, suggested the initial inhibition was due to the sensitivity of the thylakoid membrane to high temperatures (Berry and Bjorkman 1980). However, this view has been questioned recently with the observation that at moderately high temperatures photosynthetic inhibition coincides with a reversible reduction in the activity of certain Calvin cycle enzymes (Sharkey 2005). Severe heat stress is still thought to be due to injury of PSII, through direct cleavage of the D1 protein and a range of other mechanisms. Although the thermal sensitivity of PSII is not solely due to the thermal sensitivity of cell membranes, membrane properties are a major regulator of both inhibition and injury of PSII (Sharkey 2005; Allakhverdiev et al. 2008).
Adaptation of potato to high temperatures and salinity-a review
Not only does chilling exposure retard the growth and maturation of crops, but chilling damage to fresh produce during postharvest storage is also of economic importance (Figure 14.17, and see Section 11.6.5). Chilling injury is a particular problem with fresh fruit, vegetables and flowers, because storage at temperatures low enough to retard tissue respiration is still the most effective postharvest method for extending the shelf life of produce. Even in produce-handling industries, there is often insufficient appreciation of requirements and behaviour of individual crops or even specific cultivars, and losses ensue. The time taken for symptoms to develop varies greatly and is influenced by a number of factors including genotype, cultivar, stage of maturity and preharvest growth conditions. For example, with fruit stored at 1–2°C, it takes several months for chilling injury to develop in apples as a brown discolouration of the cortex, several weeks for the flesh of peaches to become mealy in texture, a number of days for avocados to show areas of grey discolouration in the flesh, and only a few hours for cucumbers to display tissue breakdown in the mesocarp. Obviously storage at 0–2°C is an excellent method for extending the storage life of apples, is moderately useful for peaches, but disastrous for cucumbers. Avocados are better kept at a higher storage temperature; the recommendation for extended storage of avocados is 6°C. Even this temperature is too low for tomato, another sub-tropical species susceptible to chilling injury. Ripe tomatoes should be stored cool, at 12°C or above, and not at refrigerator temperature.
In defining the physiological basis of chilling injury, loss of membrane integrity emerges as a major symptom and much research has been directed to elucidating the chemical and physical nature of lipoprotein membranes of species having different climatic origins. Dr John Raison and other scientists at the former CSIRO Division of Food Research in Sydney provided evidence that physical changes occur in membranes of chilling-susceptible plants during low-temperature exposure. They suggested that the molecular ordering of membrane lipids is altered in the temperature range where chilling effects become apparent. In particular, lipid composition appears to determine how membranes respond to low temperatures. Tropical species tend to have lipids with a higher proportion of saturated fatty acids (these are fatty acids such as palmitic acid which lack double bonds in their structure and therefore have higher melting points), while cool-climate plants tend to have more unsaturated fatty acids such as oleic acid. However, a consistent pattern of differences in lipid membrane composition between chilling-susceptible and chilling-resistant plants has yet to emerge and additional factors are likely to be involved. The physical nature of cell membranes remains an important point for research into chilling injury, but as yet no single physiological factor has been linked with plant susceptibility to chilling injury.
Effect of high temperature on photosynthesis in potatoes
Membrane-associated processes, such as photosynthesis and membrane transport, are typically the first to be inhibited during exposure to high temperature (Berry and Bjorkman 1980; Allakhverdiev et al. 2008). The high temperature sensitivity of PSII is thought to be due, at least in part, to its close association with the thylakoid membrane. In addition to these direct effects on metabolic function the changes in membrane fluidity during heat stress act as a signal to initiate other stress responses in the cell (Mittler et al. 2012).
At high temperatures dry matter production is often more limited by photosynthesis than by cell expansion (while at low temperatures dry matter production is more limited by cell expansion than by photosynthesis). Generally, the inhibition of photosynthesis and other growth maintaining processes during moderate or short-term heat stress results in a comparatively small reduction in the rate of dry matter production (relative growth rate) (Chapter 6.2.2; ). As temperature increases within a plant’s thermal range, the duration of growth decreases but the rate of growth increases, as shown earlier in this chapter. As a consequence, organ size at maturity may change very little in response to temperature, despite variation in growth rate. As temperatures are raised further, an increased rate of growth is no longer able to compensate for a reduction in the duration of development, and the final mass of any given organ at maturity is reduced. This response can be seen in a range of tissues including leaves, stems and fruit. A smaller organ size at maturity due to high temperature is associated with smaller cells rather than a change in cell number. This implies that cell enlargement is more sensitive to temperature than is cell division. The reduced duration of development can also limit the number of organs that are produced, e.g. grain number in wheat is reduced when plants are grown at moderately high temperatures (Stone and Nicolas 1994). Under certain conditions plants grown under moderate heat stress accumulate sugars in their leaves, indicating that translocation can be more limiting than photosynthesis, but this is not thought to be a general limitation.
20/10/2017 · Effects of high temp
on photosynthesis in potatoes cv
The effect of high temperatures on the rate of photosynthesis was studied in several potato varieties
Effect of High Temperature, Daylength, and Reduced Solar ..
Daylength, and Reduced Solar Radiation on ..
Desiree, Alpha, Katahdin, Norchip, LT1, Up-to-Date and C1-884 were studied
18/10/1976 · Photosynthesis at 25 C, high ..
Rawson HM (1988) Constraints associated with rice–wheat rotations: effects of high temperatures on the development and yield of wheat and practices to reduce deleterious effects. In AR Klatt, ed, Wheat production constraints in tropical environments. International Maize and Wheat Improvement Center (CIMMYT), Mexico DF, pp 44–62 . Link:
1977-Effects of Light Carbon Dioxide Temperature.
Tashiro T, Wardlaw IF (1989) A comparison of the effect of high temperature on grain development in wheat and rice. Ann Bot 64::59-65
Effect of leaf age on photosynthesis, carbon transport …
Enzyme activity is very responsive to temperature, as is enzyme synthesis, activation and stability. However the response of plant growth to temperature is the result of a number of complex processes involving many enzyme systems, and most likely governed by the response of the enzymes involved in CO2 fixation. The different temperature responses of C3 versus C4 photosynthesis are described next, along with temperature effects on assimilate transport and on the basic concepts of enzyme activity including the Q10: the increase in rate of respiration for a 10°C rise in temperature.
on photosynthesis in potatoes ..
Temperature effects on growth can be viewed in terms of rate multiplied by duration of growth where individual components have different temperature optima (Figure 14.7). As temperature increases within a plant’s dynamic range, duration of growth decreases but rate of growth increases. As a consequence, organ size at maturity may change very little in response to temperature despite variation in growth rate. As temperatures are raised further, an increased rate of growth is no longer able to compensate for a reduction in duration, and the final mass (or volume) of a given organ at maturity is reduced. This is providing that soil water can be maintained during this period. This response can be seen in a range of tissues including leaves, stems and fruits (and seeds). A smaller organ size at maturity due to high temperature is usually associated with smaller cells rather than a change in cell number.
"I have always been impressed by the quick turnaround and your thoroughness. Easily the most professional essay writing service on the web."
"Your assistance and the first class service is much appreciated. My essay reads so well and without your help I'm sure I would have been marked down again on grammar and syntax."
"Thanks again for your excellent work with my assignments. No doubts you're true experts at what you do and very approachable."
"Very professional, cheap and friendly service. Thanks for writing two important essays for me, I wouldn't have written it myself because of the tight deadline."
"Thanks for your cautious eye, attention to detail and overall superb service. Thanks to you, now I am confident that I can submit my term paper on time."
"Thank you for the GREAT work you have done. Just wanted to tell that I'm very happy with my essay and will get back with more assignments soon."