Water stress preconditioning of black spruce seedlings from lowland and upland sites

1994 ◽  
Vol 72 (10) ◽  
pp. 1511-1518 ◽  
Author(s):  
Abdenbi Zine El Abidine ◽  
Pierre Y. Bernier ◽  
James D. Stewart ◽  
André P. Plamondon

One-year-old seedlings from two pairs of upland – lowland populations were subjected to three cycles of drought preconditioning. During a subsequent fourth cycle, preconditioned seedlings and seedlings that had been maintained under well-watered conditions were subjected to a final soil drought. During the drought periods, small but significant differences in gas exchanges and water relations were observed between upland and lowland seedlings but the differences were not consistent either within each lowland – upland pair or over the four cycles. During the final drought period, preconditioned seedlings maintained significantly higher net photosynthesis rate, stomatal conductance, and transpiration rate than unconditioned seedlings. In contrast, no significant differences were found in midday water potential, total sugar content, or water relations parameters between preconditioned and unconditioned seedlings. The results suggest an absence of ecotypic variation with respect to drought tolerance in black spruce. They also suggest that preconditioning in black spruce seedlings occurs mostly through the acclimation of stomatal and photosynthetic mechanisms to drought, without active osmotic adjustment. Key words: Picea mariana, ecotype, gas exchanges, water relations, osmoregulation, preconditioning.

1984 ◽  
Vol 14 (1) ◽  
pp. 77-84 ◽  
Author(s):  
R. O. Teskey ◽  
C. C. Grier ◽  
T. M. Hinckley

Seasonal changes in water relations and net photosynthesis were measured over a year in current and 1-year-old foliage of Abiesamabilis (Dougl.) Forbes, a subalpine conifer. Responses were compared with maximum rates achieved in older foliage. Current-year foliage developed slowly during the growing season. Although growth began on 22 June, highest rates of stomatal conductance and net photosynthesis did not occur until September and October. One-year-old foliage had the highest rates of net photosynthesis (12.9 mg CO2•dm−2•h−1) and stomatal conductance (3.1 mm•s−1) during the summer. Net photosynthesis decreased with needle age, but foliage as old as 7 years had rates of net photosynthesis as high as 5.0 mg CO2•dm−2•h−1. There was no evidence of photosynthetic adjustment to seasonal change in temperature. The optimum temperature for photosynthesis remained at 15 ± 1.5 °C throughout the year. No water stress was observed during the summer. Xylem water potential never decreased below −1.65 MPa and was always well above the turgor loss point. The lack of any apparent water stress, combined with photosynthetic characteristics, indicated that summer was the most important season for carbon gain. These results also suggested that a strategy for competitive success by Abiesamabilis in this cold, stressful environment is minimum dependence on the carbon gain of any individual age-class of foliage. Instead trees rely on the combined photosynthetic capacity of many years of foliage.


2021 ◽  
Vol 39 ◽  
pp. 01003
Author(s):  
O.A. Ilnitsky ◽  
Y.V. Plugatar ◽  
A.V. Pashtetsky ◽  
A.T. Gil

The objective of the research is to determine the optimal zones and thresholds of soil moisture, temperature, illumination, limiting photosynthesis and transpiration of Quércus pubéscens Willd. and allowing the introduction of the species to other regions. The dependences of the net photosynthesis rate (Pn) and the transpiration rate (E) on stomatal conductivity (gs), leaf temperature (Tl), and soil moisture (Ws) are shown. The ratio of the processes of photosynthesis and respiration, under the influence of soil drought, allowed us to define their optimal values: Ws = 26 – 28%, Pn = 16 –18 μmol/m2c, Rt = 2 – 4 μmol/m2c. The relationship between the net photosynthesis rate, total respiration, and leaf temperature allowed us to determine the temperature maximum of net photosynthesis (the thermal compensation point): Pn = Rt = 2.0 μmol/m2c at Tl = 37ºC. It was found that in the absence of soil drought, the proportion of respiratory costs (Rt/Pg) from true photosynthesis is 20 – 23%, and with soil moisture of 8 – 10% increases to 55 – 58%.


1995 ◽  
Vol 73 (5) ◽  
pp. 716-722 ◽  
Author(s):  
Abdenbi Zine El Abidine ◽  
James D. Stewart ◽  
André P. Plamondon ◽  
Pierre Y. Bernier

Gas exchange and water relations were measured on seedlings from two pairs of upland and lowland black spruce (Picea mariana (Mill.) BSP) populations. The seedlings were planted under natural atmospheric conditions in exterior sand beds. Measurements were carried out on eight separate days during the summer of 1992. Diurnal and seasonal responses of gas exchange and water relations parameters to natural changes in environmental factors were analyzed for possible ecotypic differences. Differences were found among the four populations and within one of the two upland–lowland pairs. However, no differences could be linked significantly to an upland–lowland ecotypic differentiation. The physiological responses are discussed with respect to diurnal and seasonal changes in environmental factors and to similarities with results from an earlier experiment involving mature trees from the same four populations. Key words: Picea mariana, water stress, net photosynthesis, stomatal conductance.


1998 ◽  
Vol 28 (6) ◽  
pp. 820-830 ◽  
Author(s):  
Shihe Fan ◽  
Steven C Grossnickle

Physiological response of interior spruce (Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm.) to drought conditions was compared for somatic seedlings from clones G351, T703, N366, and W460. Seedlings were subjected to four cycles of progressive soil drought by withholding water. Changes in net photosynthesis (Pn), stomatal conductance (gwv), and predawn water potentials ( psi pd) were measured during and after each drought cycle. Shoot tissue water relations parameters were measured using pressure-volume analysis at the beginning and end of the fourth drought cycle. When comparing drought cycle 1 with drought cycle 4, clones G351, N366, and T703 showed significantly reduced Pn, but gwv of all clones was not affected. Net photosynthesis and gwv decreased with psi pd more rapidly in clone W460 than in the remaining clones. When rewatered after drought, clone T703 had the most rapid Pn and gwv recovery whereas clone G351 had the slowest recovery of Pn and gwv. Over four drought cycles, all clones photosynthesized at progressively lower psi pd, but adjustments in tissue water relations parameters were marginal. These results implied that gas exchange parameters were more sensitive than shoot tissue water relations parameters in detecting clonal variation in the physiological response of interior spruce under simulated drought conditions.


2020 ◽  
Vol 16 (5) ◽  
pp. 802-807
Author(s):  
Shashi Bala ◽  
Vinod K. Nigam ◽  
Ambarish S. Vidyarthi

Background: Annona squamosa L. (custard apple) is a tropical fruit known for its sweet taste, distinct flavour, and pleasant, aromatic creamy pulp. The fruit is traditionally used as different folk medicines by tribal community in India. The present study was focussed on the nutritional properties of custard apple based products like pulp, juice, jam, jelly and powder. Methods: Standard ICP-OES and recognized methods of analysis were used for investigation of minerals and biochemical constituents of process products of custard apple. Results: The proximate analysis showed the highest quantity of vitamin C as 32.5 mg/100g, 16.4 mg/100g, 15.8 mg/100g 16.85 mg/100g and 12.3 mg/100g in pulp, jam, jelly, juice and in powder with a total sugar content of 20.96, 51.26, 49.83, 13.17 and 33.5 g/100g for pulp, jam, jelly, juice and powder respectively. The content of calcium in different products of custard apple was observed as 64.25, 58.15, 55.20, 58.20 and 138.35 mg/100g while, the amount of iron as constituent was found as 2.8, 2.25, 2.25, 2.65, 5.45 mg/100g respectively. The observed value of potassium in pulp, juice, jam, jelly and powder was recorded as 428.00, 545.50, 415.0, 411.9 and 1094.5 mg/100g while the concentration of magnesium was found as 54.5 mg/100g in pulp, 65.0 mg/100g in juice, 45.5 mg/100g in jam, 41.2 mg/100g in jelly and 130.4 mg/100g in powder respectively. The study of analytes like As, Pb, Ni and Sn in custard apple products were found below the level of toxicity. Conclusion: The results obtained suggest that these underutilized fruits could greatly add in the improvement of the nutrition of consumers and promote good human health.


1993 ◽  
Vol 1 (2) ◽  
pp. 99-108 ◽  
Author(s):  
P. Robert ◽  
M.F. Devaux ◽  
A. Qannari ◽  
M. Safar

Multivariate data treatments were applied to mid and near infrared spectra of glucose, fructose and sucrose solutions in order to specify near infrared frequencies that characterise each carbohydrate. As a first step, the mid and near infrared regions were separately studied by performing Principal Component Analyses. While glucose, fructose and sucrose could be clearly identified on the similarity maps derived from the mid infrared spectra, only the total sugar content of the solutions was observed when using the near infrared region. Characteristic wavelengths of the total sugar content were found at 2118, 2270 and 2324 nm. In a second step, the mid and near infrared regions were jointly studied by a Canonical Correlation Analysis. As the assignments of frequencies are generally well known in the mid infrared region, it should be useful to study the relationships between the two infrared regions. Thus, the canonical patterns obtained from the near infrared spectra revealed wavelengths that characterised each carbohydrate. The OH and CH combination bands were observed at: 2088 and 2332 nm for glucose, 2134 and 2252 nm for fructose, 2058 and 2278 nm for sucrose. Although a precise assignment of the near infrared bands to chemical groups within the molecules was not possible, the present work showed that near infrared spectra of carbohydrates presented specific features.


2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Yu Kryzhova ◽  
◽  
O Deyak ◽  

The nature of nutrition is the most important factor determining human health. Proper healthy nutrition maintains health, plays an important role in preventing chronic diseases in modern humans. The level of food product quality must meet the human physiological needs for nutrients and energy, and healthy nutrition also includes the concept of the preventive effect of food, or food as a risk factor for chronic non-communicable diseases. When nutrients are in improper proportions, nutrition is considered incorrect, unhealthy, irrational, and may play a role as a risk factor for the development of human diseases. The paper substantiates the use of beet syrup and beet in ketchup technology and the benefits of the developed recipes for human health. It also covers the physicochemical composition of beet syrup, which contains 93.5% dry matter, and sugar composition and content in beet syrup: glucose, fructose, sucrose, and maltose, the total sugar content is 48.8 g/100 g that is 50.2 g/100 g less than common sugar. The ratio of prescription ingredients, established by experimental investigations on organoleptic parameters, is substantiated. The water activity index was investigated, which constituted 0.92 in the second sample, 0.93 – in the first sample, and 0.93 – in the control sample, which will have a positive effect on their shelf life. The examination of the chemical composition showed that the protein content in the first sample increased by 33%, in the second sample – by 56% compared to the control sample; the sugar content reduced by 42.7% in the first sample and by 50.6% in the second sample; the vitamin C content increased; the fiber content increased 3 times; the developed products are enriched with iron, phosphorus, and potassium. The Nutri-score calculation showed that the samples developed according to formulas №1 and №2 belong to categories A and B and are more balanced and beneficial to human health, which indicates the high nutritional value of the products. In terms of the energy value, the developed samples have an advantage over the control. The energy value (kcal/100 g) of the first sample is 100, the second sample – 89.5, and the control sample – 104.


2013 ◽  
Vol 25 (16) ◽  
pp. 9421-9422 ◽  
Author(s):  
G. Peng ◽  
E.V. Davis ◽  
L.X. Wang ◽  
C.W. Zhang

2017 ◽  
Vol 9 (10) ◽  
pp. 168 ◽  
Author(s):  
Francisco V. da S. Sá ◽  
Hans R. Gheyi ◽  
Geovani S. de Lima ◽  
Emanoela P. de Paiva ◽  
Pedro D. Fernandes ◽  
...  

This study aimed to evaluate the interaction between the fertilization with nitrogen (N) and phosphorus (P) and irrigation with saline water on the water relations, gas exchanges and chlorophyll a fluorescence in West Indian cherry in the vegetative stage. The study was carried out in protected environment, using lysimeters filled with clay loam Regolithic Neosol, with low P content, installed in a randomized block design, arranged in a factorial scheme with five levels of electrical conductivity of irrigation water (ECw), and four managements of P and N fertilization, with three replicates and one plant per plot. Along the experiment, water relations, gas exchanges and chlorophyll a fluorescence were evaluated in West Indian cherry plants. The increase in irrigation water salinity reduces the gas exchanges of the plants, but the increment of 40% in N supply increases the photosynthetic activity of West Indian cherry at recommendation levels higher than 100:100% of the P/N ratio, when irrigated with ECw of up to 3.0 dS m-1. The combined action of N and P, at doses of 140:140% N/P recommendation, increases leaf turgor in the plants, regardless of the ECw level. The increment of 40% in N dose reduces the effects of salinity on the initial fluorescence of chlorophyll a in West Indian cherry irrigated with up to 2.2 dS m-1.


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