Winter water relations of native and introduced evergreens in interior Alaska

1980 ◽  
Vol 58 (1) ◽  
pp. 94-99 ◽  
Author(s):  
Joanne E. Cowling ◽  
Richard A. Kedrowski
Keyword(s):  
Lodgepole Pine ◽  
Pine Needles ◽  
Drought Tolerant ◽  
Interior Alaska ◽  
Tolerant Plants ◽  
Water Potentials ◽  
Relative Water ◽  
Yellow Pine ◽  
Spruce Needles ◽  
Water Contents

In view of wintertime browning of needles of pines introduced in Alaska, winter desiccation damage was suspected. However, examination of field xylem water potentials and relative water contents indicated little water stress in pine needles but severe stress in sunny native spruce needles and slightly less stress in shaded needles. Spruce were typical of drought tolerant plants, exhibiting field xylem water potentials of –10 to –40 bars and field relative water contents of 88 to 99%, closing stomates at water contents of 71 to 92%, and maintaining cuticular conductances from 0.013 to 0.088 cm s−1. In contrast, pines were drought avoiding, exhibiting field xylem water potentials of 0 bars and field water contents of 100%, keeping stomates closed all winter, and maintaining cuticular conductances from 0 to 0.033 cm s−1 and 0 to 0.074 cm s−1 in lodgepole pine and yellow pine, respectively. Needles of all species photosynthesized at temperatures from 0 to 10 °C with rates in spruce being 10 times those in yellow pine and 3 times those in lodgepole pine. While spruce needles had significantly more carbohydrate reserves at the end of the winter than did pine needles, the latter were apparently not severely carbohydrate depleted.

Water stress affects the productivity, growth components, competitiveness and water relations of phalaris and white clover growing in a mixed pasture

1992 ◽  
Vol 43 (3) ◽  
pp. 659 ◽  
Author(s):  
L Guobin ◽  
DR Kemp ◽  
GB Liu
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
White Clover ◽  
Leaf Growth ◽  
Leaf Water ◽  
Water Potentials ◽  
Relative Water ◽  
Dry Conditions ◽  
Leaf Appearance ◽  
Water Contents

The effect of water stress during summer and recovery after rain on herbage accumulation, leaf growth components, stomatal conductance and leaf water relations of white clover (Trifolium repens cv. Haifa) and phalaris (Phalaris aquatica cv. Australian Commercial) was studied in an established mixed pasture under dryland (dry) or irrigated (wet) conditions. Soil water deficits under dry conditions reached 150 mm and soil water potentials in the top 20 cm declined to nearly -2 MPa after 50 days of dry weather. Water stress severely restricted growth of both species but then after rain fell, white clover growth rates exceeded those of phalaris. Under irrigation, white clover produced twice the herbage mass of phalaris but under dry conditions herbage production was similar from both species. Leaf appearance rates per tiller or stolon were slightly higher for white clover than phalaris but were reduced by 20% under water stress in both species. Leaf or petiole extension rates were more sensitive to water stress than leaf appearance rates and declined by 75% in phalaris and 90% in white clover. The ratio of leaf or petiole extension rates on dry/wet treatments was similar for both species in relation to leaf relative water contents, but in relation to leaf water potentials phalaris maintained higher leaf growth rates. Phalaris maintained a higher leaf relative water content in relation to leaf water potentials than did white clover and also maintained higher leaf water potentials in relation to the soil water potential in the top 20 cm. Stomata1 conductances for both species declined by 80-90% with increasing water stress, and both species showed similar stomatal responses to bulk leaf water potentials and leaf relative water contents. It is suggested that the poorer performance of white clover under water stress may be due principally to a shallower root system than phalaris and not due to any underlying major physiological differences. The white clover cultivar used in this study came from the mediterranean region and showed some different responses to water stress than previously published evidence on white clover. This suggests genetic variation in responses to water stress may exist within white clover. To maintain white clover in a pasture under dry conditions it is suggested that grazing practices aim to retain a high proportion of growing points.

scholarly journals Proline, Soluble Sugar, Leaf Starch and Relative Water Contents of Four Maize Varieties in Response to Different Watering Regimes

2016 ◽  
Vol 49 (3) ◽  
pp. 51-62 ◽  
Author(s):  
F.B. Anjorin ◽  
S.A. Adejumo ◽  
L. Agboola ◽  
Y.D. Samuel
Keyword(s):  
Water Content ◽  
Relative Water Content ◽  
Agricultural Research ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Starch Accumulation ◽  
Drought Tolerant ◽  
Maize Varieties ◽  
Relative Water ◽  
Water Contents

Abstract The purpose of this study was to evaluate the response of four maize varieties to different simulated watering regimes in term of proline, starch and soluble sugar contents as well as relative water content. Maize seeds were planted in 64 plastic pots of 20 litre capacity, arranged in a factorial fitted in completely randomized design (CRD), with four replications in the screen house of the Institute of Agricultural Research and Training (I.A.R&T), Moor Plantation Ibadan. The watering was done based on the designated field capacities (FC) of 25, 50, 75 and 100%. Fresh leaf samples were collected five weeks after planting and at the end of each stress period. The proline, soluble sugar, leaf starch and the relative water contents in the leaves were estimated. The results obtained showed that watering regime significantly influenced the leaf starch, soluble sugar, proline and relative water contents. The varieties also differ significantly in the proline, soluble sugar content, leaf starch and the relative water contents. Watering regime and variety interaction was significant for soluble sugar, starch, proline and the relative water content. Highest soluble sugar of 1.28 mg/g and proline of 35.70 μmol/g FW were obtained when FC was 25% and lowest when watering level was optimum. The starch and relative water contents were optimum under full watering (100% FC) and lowest when field capacity was 25%. Variations were observed with regards to different maize varieties. ART98SW6-OB accumulated the highest quantity of soluble sugar and proline under 25 and 50% field capacities alongside DTESYN, which is a drought tolerant maize variety. It could be concluded that water stress increased production of soluble sugar and proline, while water availability increases relative water content and favors starch accumulation. The consideration of these metabolites alongside other physiological features is a very fast and reliable method for drought tolerant plant selection even at the plant seedling growth stage.

Relationships between physiological traits and productivity of sugarcane in response to water deficit

2012 ◽  
Vol 152 (1) ◽  
pp. 104-118 ◽  
Author(s):  
M. DE A. SILVA ◽  
J. L. JIFON ◽  
J. A. G. DA SILVA ◽  
C. M. DOS SANTOS ◽  
V. SHARMA
Keyword(s):  
Water Deficit ◽  
Field Studies ◽  
Water Deficit Stress ◽  
Chlorophyll Contents ◽  
Physiological Variables ◽  
Drought Tolerant ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
Sugarcane Productivity ◽  
Response To Water

SUMMARYThe relationships between physiological variables and sugarcane productivity under water deficit conditions were investigated in field studies during 2005 and 2006 in Weslaco, Texas, USA. A total of 78 genotypes and two commercial varieties were studied, one of which was drought-tolerant (TCP93-4245) and the other drought-sensitive (TCP87-3388). All genotypes were subjected to two irrigation regimes: a control well-watered treatment (wet) and a moderate water-deficit stress (dry) treatment for a period of 90 days. Maximum quantum efficiency of photosystem II (Fv/Fm), estimated chlorophyll content (SPAD index), leaf temperature (LT), leaf relative water content (RWC) and productivity were measured. The productivity of all genotypes was, on average, affected negatively; however, certain genotypes did not suffer significant reduction. Under water deficit, the productivity of the genotypes was positively and significantly correlated with Fv/Fm, SPAD index and RWC, while LT had a negative correlation. These findings suggest that genotypes exhibiting traits of high RWC values, high chlorophyll contents and high photosynthetic radiation use efficiency under low moisture availability should be targeted for selection and variety development in programmes aimed at improving sugarcane for drought prone environments.

scholarly journals Cold hardiness of white spruce, black spruce, jack pine, and lodgepole pine needles during dehardening

2017 ◽  
Vol 47 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Qing-Lai Dang
Keyword(s):  
Picea Glauca ◽  
Pinus Banksiana ◽  
Cold Hardiness ◽  
Black Spruce ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Visual Assessment ◽  
Jack Pine ◽  
Pine Needles ◽  
Late Winter

Conifer winter damage results primarily from loss of cold hardiness during unseasonably warm days in late winter and early spring, and such damage may increase in frequency and severity under a warming climate. In this study, the dehardening dynamics of lodgepole pine (Pinus contorta Dougl. ex. Loud), jack pine (Pinus banksiana Lamb.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) were examined in relation to thermal accumulation during artificial dehardening in winter (December) and spring (March) using relative electrolyte leakage and visual assessment of pine needles and spruce shoots. Results indicated that all four species dehardened at a similar rate and to a similar extent, despite considerably different thermal accumulation requirements. Spring dehardening was comparatively faster, with black spruce slightly hardier than the other conifers at the late stage of spring dehardening. The difference, however, was relatively small and did not afford black spruce significant protection during seedling freezing tests prior to budbreak in late March and early May. The dehardening curves and models developed in this study may serve as a tool to predict cold hardiness by temperature and to understand the potential risks of conifer cold injury during warming–freezing events prior to budbreak.

Lower limit of available water for three plant species grown on a medium-textured soil in southwestern Saskatchewan

1991 ◽  
Vol 71 (2) ◽  
pp. 247-252 ◽  
Author(s):  
H. W. Cutforth ◽  
P. G. Jefferson ◽  
C. A. Campbell
Keyword(s):  
Key Words ◽  
Lower Limit ◽  
Plant Species ◽  
Spring Wheat ◽  
Soil Factors ◽  
Available Water ◽  
Water Potentials ◽  
Lower Limits ◽  
Water Contents

Numerous researchers estimate and report laboratory-determined lower limit of available water contents using −1.5 MPa water potentials. For medium-textured soils, laboratory-measured lower limits should be determined at potentials of at least −4 MPa, and possibly −10 MPa, when using pressure membrane procedures. However, because the lower limit of available water is dependent upon environmental, plant and soil factors, we agree with Ratliff et al. (1983) that field-measured lower limits are preferable to laboratory-measured lower limits. Field-measured lower limits of available water did not vary markedly between spring wheat, alfalfa and grass. Key words: Lower limit of available water, wheat, alfalfa, grass

Drought Response of Rice in Northeastern Thailand Assessed via Fourier Transform Infrared Spectroscopy

2021 ◽  
Vol 74 ◽  
Author(s):  
Piyaporn Phansak ◽  
Supatcharee Siriwong ◽  
Nantawan Kanawapee ◽  
Kanjana Thumanu ◽  
Wuttichai Gunnula ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Drought Stress ◽  
Lignin Content ◽  
Principal Component ◽  
Fourier Transform Infrared ◽  
Breeding Programs ◽  
Treatment Groups ◽  
Drought Tolerant ◽  
Relative Water ◽  
Rice Landrace

Abstract Drought isa major constraint in many rainfed areas and affects rice yield. We aimed to characterize the physiological changes in rice in response to drought using Fourier transform infrared (FTIR) spectroscopy. Eighty rice landrace seedlings were subjected to drought in the greenhouse using a PEG 6000. Physiological parameters, including total chlorophyll content, relative water content, electrolyte leakage, and biochemical changes were evaluated. Based on the FTIR results, the landraces were divided into three main groups: tolerant, moderately tolerant, and susceptible. Principal component analysis revealed spectral differences between the control and drought stress treatment groups. Lipid, pectin, and lignin content increased after drought stress. The biochemical components of plants at different drought tolerance levels were also compared. The lipid (CH2 and CH3), lignin (C=C), pectin (C=O), and protein (C=O, N–H) contents were the highest in the drought-tolerant cultivars, followed by the moderately tolerant and susceptible cultivars, respectively. Cultivar 17 and 49 were the most tolerant, and the functional groups were identified and characterized using FTIR. Overall, these results will be useful in selecting parental cultivars for rice breeding programs.

scholarly journals Differential Activity of Antioxidant Enzymes and Physiological Changes in Wheat (Triticum aestivum L.) Under Drought Stress

2019 ◽  
Vol 11 (2) ◽  
pp. 266-276
Author(s):  
Kamal MIRI-HESAR ◽  
Ali DADKHODAIE ◽  
Saideh DOROSTKAR ◽  
Bahram HEIDARI
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Field Capacity ◽  
Triticum Aestivum L ◽  
Plant Production ◽  
Breeding Programs ◽  
Drought Tolerant ◽  
Severe Water Stress ◽  
Significant Difference ◽  
Relative Water

Drought stress is one of the most significant environmental factors restricting plant production all over the world. In arid and semi-arid regions where drought often causes serious problems, wheat is usually grown as a major crop and faces water stress. In order to study drought tolerance of wheat, an experiment with 34 genotypes including 11 local and commercial cultivars, 17 landraces, and six genotypes from International Maize and Wheat Improvement Center (CIMMYT) was conducted at the experimental station, School of Agriculture, Shiraz University, Iran in 2010-2011 growing season. Three different irrigation regimes (100%, 75% and 50% Field Capacity) were applied and physiological and biochemical traits were measured for which a significant difference was observed in genotypes. Under severe water stress, proline content and enzymes’ activities increased while the relative water content (RWC) and chlorophyll index decreased significantly in all genotypes. Of these indices, superoxide dismutase (SOD) and RWC were able to distinguish tolerant genotypes from sensitives. Moreover, yield index (YI) was useful in detecting tolerant genotypes. The drought susceptibility index (DSI) varied from 0.40 to 1.71 in genotypes. These results indicated that drought-tolerant genotypes could be selected based on high YI, RWC and SOD and low DSI. On the whole, the genotypes 31 (30ESWYT200), 29 (30ESWYT173) and 25 (Akbari) were identified to be tolerant and could be further used in downstream breeding programs for the improvement of wheat tolerance under water limited conditions.

Leaf area development of ABA-deficient and wild-type peas at two levels of nitrogen supply

2003 ◽  
Vol 30 (7) ◽  
pp. 777 ◽  
Author(s):  
Ian C. Dodd
Keyword(s):  
Growth Response ◽  
Leaf Growth ◽  
Nitrogen Supply ◽  
Genotypic Differences ◽  
Wild Type ◽  
Ethylene Evolution ◽  
Relative Water ◽  
Ca 50 ◽  
Area Development ◽  
Water Contents

The ABA-deficient wilty pea (Pisum sativum L.) and its wild-type (WT) were grown at two levels of nitrogen supply (0.5 and 5.0 mM) for 5–6 weeks from sowing, to determine whether leaf ABA status altered the leaf growth response to N deprivation. Plants were grown at high relative humidity to prevent wilting of the wilty peas. Irrespective of N supply, expanding wilty leaflets had ca 50% less ABA than WT leaflets but similar ethylene evolution rates. Fully expanded wilty leaflets had lower relative water contents (RWC) and were 10–60% smaller in area (according to the node of measurement) than WT leaflets. However, there were no genotypic differences in plant relative leaf expansion rate (RLER). Growth of both genotypes at 0.5 mM N increased the RWC of fully expanded leaflets, but did not alter ethylene evolution or ABA concentration of expanding leaflets. Plants grown at 0.5 mM N showed a 20–30% reduction in RLER, which was similar in magnitude in both wilty and WT peas. Thus,�leaf ABA status did not alter the leaf growth response to N deprivation.

Sign in / Sign up

Export Citation Format

Share Document