Some cells respire aerobically, using oxygen, while others undergo anaerobic respiration, without using oxygen. The process involves a set of chemical reactions to convert chemical energy from the glucose molecules into ATP molecules. Oxygen plays no part during this stage, so it is called anaerobic respiration. Aerobic Respiration This process takes place in specialized structures within the cell called mitochondria, and uses the products of glycolysis, the pyruvate molecules, to release energy, along with CO2 and water as the by-products of the reaction.
The energy released is stored in the form of ATP molecules. Usually, a total of 38 ATP molecules is produced. Differences between Photosynthesis and Cellular Respiration Photosynthesis takes place in two stages of the light reactions and the dark reactions.
Cellular respiration involves aerobic glycolysis and anaerobic respiration. Photosynthesis takes place only when there is sunlight.
Cellular respiration occurs at all times. Introduction The blue oak Quercus douglasii Hook. As this region is highly sensitive to climate change Kueppers et al. Kueppers et al. However, the extent of drought that blue oaks can withstand is not entirely clear and may also depend on changes in the availability of groundwater, as groundwater provides the lifeline for persistence through annual summer drought Miller et al. Because the trees are winter deciduous, the growing season begins in the spring when soil moisture is often high.
The moisture rapidly depletes and the majority of the period of foliation coincides with a period of extremely low soil moisture, negligible precipitation, high incoming solar radiation and high air temperatures Xu and Baldocchi Seasonal adjustments in leaf structure and function enable evergreen Mediterranean species to survive the annual summer drought Tenhunen et al.
Much less is known, however, about leaf level adjustments in winter-deciduous Mediterranean species Damesin and Rambal , Damesin et al. As such, it is important to understand how the blue oaks are functioning—both in terms of net carbon assimilation and conversion or dissipation of absorbed photosynthetic photon flux density PPFD —under the current annual drought in order to understand how future drought scenarios may affect them.
The California Mediterranean oak savanna is a particularly harsh environment. Air temperature, leaf-to-air vapor pressure deficit and PPFD remain high throughout the summer Kobayashi et al.
Despite these conditions leaves persist on the trees well into the fall Ryu et al. This conundrum of high photosynthetic capacity during extreme drought results in ecosystem models consistently underestimating uptake of CO2 at deciduous, drought-stressed ecosystems Vargas et al.
The discs were placed in six groups containing 25 discs in each group according to the reading ranges , , , , , Each group of 25 discs were put in paper bags, placed in a forced air chamber at 70 oC. After 48 h the material was ground in a mill Wiley with a 20 mesh sieve and stored in hermetically sealed flasks for later analysis.
The Nessler method Jackson, was used to determine the nitrogen after oxidizing the plant material by sulfuric digestion. Chlorophyll fluorescence determination: After measuring with the SPAD, the room temperature chlorophyll fluorescence measurements were carried out on the leaf discs using the mini portable pulse amplitude modulation fluorometer MINI-PAM, Walz, Effeltrich, Germany. The leaf discs were pre-darkened for 30 min so that the all reaction centres were "open" all primary acceptors oxidized and heat dissipation was minimal.
The maximal fluorescence Fmax was determined by a 0. The variable fluorescence was determined by the difference between Ff and Fmax. The characteristic fluorescence levels and quenching coefficients was defined in agreement with a proposal for standard nomenclature at a fluorescence workshop Van Kooten and Snel, Determination coefficient values ranged from 0.
Relationships among the total chlorophyll content and the SPAD readings were established in several plant species Marquard and Tipton, ; Yadava, ; Schaper and Chacko, In these studies, the fitted model was the simple linear mathematical model. In this work, were suggesting that for papaya the linear mathematical model was not the best model. Chlorophyll a is more intensely degraded than chlorophyll b Wolf, Figure 3 shows the relationship for the SPAD readings, the nitrogen contents and the total chlorophyll contents in both papaya groups.
This figure shows that the decrease in the total N content fell sharply when the values obtained by the SPAD were lower than The Fmax variable figure 4B presented a direct linear relationship with the SPAD values, along all the reading band of the portable chlorophyll meter. The Fmax variable corresponds to the state of complete reduction of the plastoquinone pool PQ and is considered proportional to the total chlorophyll content of the sample Miranda et al.
The data presented here figure 4 showed that the photochemical process was impaired in papaya leaves from the 'Solo' and 'Formosa' groups that presented SPAD values less than These qp data indicate disturbances in the electron transport or even possible damage in the reducing power of the biochemical process.
From this value, these fluorescence variables remained practically unaltered. The qN and NPQ variables represent a fraction of the energy absorbed, such as the excitation of the photosynthesizing pigments, that is dissipated as heat or non-radioative energy thermal energy. The seedlings were kept with the same management and in the same conditions in the greenhouse after transplanting.
Soil water potential was monitored by Watermark sensors Spectrum Technologies, USA placed at 15 cm in depth and 5 cm distant from the plant. Each sensor was installed in one of the two plants that formed each repetition in the treatment, that is, four sensors were used for each treatment.
After transplanting, the plants were conducted on espalier system and watered daily with a watering can until percolation was observed at the bottom of each pot. At 23 and 30 days after transplanting DAT , 1. The plants were not watered for seven consecutive days and the watering was resumed at 43 DAT.
The evaluations were performed with the natural incident light on the sampled leaf area 6 cm2 in the apparatus chamber.Plant cells, after creating sugar molecules through photosynthesis, undergo cellular respiration to create ATP molecules. Google Scholar Lichtenthaler, H. This is a preview of subscription content, log in to check access. Google Scholar Santarius, K. However there is no information on the use of this meter for the papaya species.
Conformational Flexibility of Macromolecules and Ecological Adaptation.
Usually, a total of 38 ATP molecules is produced. In this temperature range, the dark respiration rate was reversibly enhanced, and an increased number of polyribosomes indicated repair after the primary injury. However, to determine the real concentration of the chlorophyll content in a sample, the ratio between the values obtained by the meter and the real chlorophyll content must be established. CrossRef Google Scholar Copyright information. Google Scholar Semikhatova, O. Photosynthesis involves conversion of one type of energy into another: light energy into chemical energy.
At the end of the experiment 49 DAT , we found that the PPS plants had the highest root dry mass and the greatest leaf area than the other treatments Table 1. The Ff variable represents the fluorescence emission from the complex antenna, even before the arrival of the photon energy to the center of the photosystem II reaction.