scholarly journals PHYSIOLOGICAL RESPONSES OF YOUNG APPLE TREES ON 3 ROOTSTOCKS TO DROUGHT STRESS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 573a-573 ◽  
Author(s):  
Rodney T. Fernandez ◽  
Ronald L. Perry ◽  
James A. Flore
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Fluorescence Quenching ◽  
Physiological Responses ◽  
Apple Trees ◽  
Stress Cycle ◽  
Before And After ◽  
Variable Chlorophyll Fluorescence ◽  
And Control

`Imperial Gala' on M.9 EMLA, MM.111 and Mark rootstocks were planted in a rain exclusion shelter. Two drought stress periods lasting approximately 1 month each were imposed during 1991. Water was supplied at 2 liters per day per tree before and after each drought cycle while water was withheld from half of the trees during the drought stresses. Maximal and variable chlorophyll fluorescence and fluorescence quenching were significantly reduced by the drought stress with M.111 generally affected first and with the largest difference between drought and control followed by Mark and then M.9. Leaf and stomatal conductance, assimilation and transpiration usually occurred first and were lowest for M.9 followed by Mark and then M.111 during the first stress cycle while Mark responded more rapidly and to a greater extent than M.9 and M.111 during the second stress. Water potential was lower for the stressed trees during both stress periods but osmotic and turgor potentials were reduced only during the first stress period. Changes in water relations were noticed first and to a greater extent for Mark followed by M.9 with M.111 exhibiting the least sensitivity and differences.

scholarly journals Effects of Drought and Rehydration on the Physiological Responses of Artemisia halodendron

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 793
Author(s):  
Juanli Chen ◽  
Xueyong Zhao ◽  
Yaqiu Zhang ◽  
Yuqiang Li ◽  
Yongqing Luo ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Membrane Permeability ◽  
Chlorophyll Content ◽  
Physiological Responses ◽  
Severe Drought ◽  
Native Plant ◽  
Chlorophyll Fluorescence Parameters ◽  
Artemisia Halodendron ◽  
Effects Of Drought

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

scholarly journals Physiological responses of two halophytic grass species under drought stress environment

2016 ◽  
Vol 75 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Zamin Shaheed Siddiqui ◽  
Huda Shahid ◽  
Jung-Il Cho ◽  
Sung-Han Park ◽  
Tae-Hun Ryu ◽  
...  
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Water Deficit ◽  
Physiological Responses ◽  
Biomass Accumulation ◽  
Photosynthetic Performance ◽  
Grass Species ◽  
Free Proline ◽  
Relative Water ◽  
Halophytic Grasses

AbstractThe physiological responses of two halophytic grass species, Halopyrum mucronatum (L.) Staph. and Cenchrus ciliaris (L.), under drought stress were evaluated. Biomass accumulation, relative water content, free proline, H2O2content, stomatal conductance, photosynthetic performance and quantum yield (Fv/Fmratio) were studied. Under drought conditions, these halophytic plants expressed differential responses to water deficit. Stomatal conductance and free proline content were higher in H. mucronatum than in C. ciliaris, while H2O2content in H. mucronatum was substantially lower than in C. ciliaris. Performance index showed considerable sensitivity to a water deficit condition, more so in C. ciliaris than in H. mucronatum. Results were discussed in relation to comparative physiological performance and antioxidant enzymes activity of both halophytic grasses under drought stress.

scholarly journals Drought Response of Young Apple Trees on Three Rootstocks. II. Gas Exchange, Chlorophyll Fluorescence, Water Relations, and Leaf Abscisic Acid

1997 ◽  
Vol 122 (6) ◽  
pp. 841-848 ◽  
Author(s):  
R. Thomas Fernandez ◽  
Ronald L. Perry ◽  
James A. Flore
Keyword(s):  
Abscisic Acid ◽  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Gas Exchange ◽  
Water Relations ◽  
Acid Content ◽  
Recovery Period ◽  
Leaf Conductance ◽  
Apple Trees ◽  
Abscisic Acid Content

`Imperial Gala' apple trees (Malus ×domestica Borkh.) on M.9 EMLA, MM.111, and Mark rootstocks were subjected to two drought-stress and recovery periods in a rainshelter. Water relations, gas-exchange parameters per unit leaf area and per tree, chlorophyll fluorescence, and leaf abscisic acid content were determined during each stress and recovery period. Whole-plant calculated gas exchange best indicated plant response to drought stress, with consistent reductions in CO2 assimilation, transpiration, and leaf conductance. Variable and maximal chlorophyll fluorescence and fluorescence quenching were not as sensitive to stress. Other fluorescence parameters showed little difference. The most consistent decreases due to stress for gas exchange per square meter were in transpiration and leaf conductance, with few differences in CO2 assimilation and fewer for mesophyll conductance, internal CO2 concentration, and water-use efficiency. Leaf water potential was consistently lower during drought stress and returned to control values upon irrigation. Leaf abscisic acid content was higher for drought-stressed trees on M.9 EMLA than control trees during the stress periods but inconsistently different for the other rootstock treatments. Trees on M.9 EMLA were least affected by drought stress, MM.111 was intermediate, and Mark was the most sensitive; these results are consistent with the growth data.

scholarly journals Influence of Inverse Day/Night Temperature on Ozone Sensitivity and Selected Morphological and Physiological Responses of Cucumber

1993 ◽  
Vol 118 (5) ◽  
pp. 649-654 ◽  
Author(s):  
Madhoolika Agrawal ◽  
Donald T. Krizek ◽  
Shashi B. Agrawal ◽  
George F. Kramer ◽  
Edward H. Lee ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Growth Response ◽  
Chlorophyll Concentration ◽  
Dry Weight ◽  
Fresh Weight ◽  
Night Temperature ◽  
Ozone Sensitivity ◽  
Variable Chlorophyll Fluorescence ◽  
Cultivar Difference

Cucumis sativus L. (cvs. Poinsett and Ashley) plants were grown from seed in a growth chamber at a +10C (28/18) or a -10C (18/28) difference (DIF) between day temperature (DT) and night temperature (NT) on a 12-hour photoperiod for 24 days prior to ozone (O3) fumigation (3 hours at 0.5 umol·mol-1). Negative DIF, compared to +DIF, reduced plant height, node count, fresh weight, dry weight, and leaf area in both cultivars. Photosynthetic rate (Pn), chlorophyll concentration, and variable chlorophyll fluorescence (Fv) were lower and O3 injury and polyamine concentrations were higher at -DIF than at +DIF. Ozone fumigation generally increased leaf concentration of polyamines and reduced Pn, stomatal conductance, and chlorophyll fluorescence. `Poinsett' generally had a higher specific leaf mass and higher concentrations of chlorophyll a and polyamines than did `Ashley', but there was no cultivar difference in O3 injury, growth response, Pn, or stomatal conductance.

NITROGENASE ACTIVITY, PHOTOSYNTHESIS AND TOTAL NONSTRUCTURAL CARBOHYDRATES IN COWPEA DURING AND AFTER DROUGHT STRESS

1990 ◽  
Vol 70 (4) ◽  
pp. 1005-1012 ◽  
Author(s):  
S. PARARAJASINGHAM ◽  
D. P. KNIEVEL
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Vigna Unguiculata ◽  
Nitrogenase Activity ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Plant Parts ◽  
Total Nonstructural Carbohydrates ◽  
Nonstructural Carbohydrate ◽  
And Control

Greenhouse experiments were conducted to determine whether depressed nitrogenase activity (NA) of cowpea (Vigna unguiculata (L.) Walp.) nodules during drought stress is associated with altered carbohydrate supply to the nodules. Nitrogenase activity of the nodules, midday abaxial stomatal conductance, leaf net photosynthesis and mg total nonstructural carbohydrate (TNC) g−1 dry weight of several plant parts were measured in cowpea subjected to and recovering from drought stress periods of 0, 4 and 8 days. In addition, cowpea plants were shaded or partially defoliated (75% leaf removal) to limit carbohydrate supply to the nodules of well-watered plants. Stomatal conductance, leaf net photosynthesis and nodule NA declined 60, 62 and 90%, respectively, within 4 d of withholding water. After 8 d of drought stress, leaf net photosynthesis and nodule NA were near zero. Stomatal conductance and leaf net photosynthesis returned to the level of unstressed plants within 24 h following rewatering while recovery of NA was delayed. Shading and defoliation of cowpea plants under well watered conditions decreased NA 62 and 44%, respectively. TNC concentrations of leaves, petioles, stems, roots and nodules did not differ appreciably between drought stressed and control plants. In contrast, TNC concentrations of shoot plant parts from shaded or defoliated plants declined significantly compared to controls and nodule TNC concentrations declined in shaded plants. The decline in NA by cowpea nodules during drought stress did not appear to be directly associated with carbohydrate supply to the nodules, but rather the result of a new equilibrium attained with overall limited plant growth under the stress.Key words: Vigna unguiculata (L.) Walp., nitrogenase activity, drought stress recovery, assimilate stress, shading, defoliation, total nonstructural carbohydrate

scholarly journals Association of Physiological Responses and Root Distribution Patterns to Ratooning Ability and Yield of the Second Ratoon Cane in Sugarcane Elite Clone

2018 ◽  
Author(s):  
Saranya Chumphu ◽  
Nuntawoot Jongrungklang ◽  
Patcharin Songsri
Keyword(s):  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Root Distribution ◽  
Block Design ◽  
Physiological Responses ◽  
Soil Layer ◽  
Distribution Patterns ◽  
Germination Percentage ◽  
Cane Yield ◽  
Soil Layers

The objective of this study was to determine the association of physiological responses and root distribution patterns on yield of the second ratoon cane and the relationships among these traits. Seventeen sugarcane genotypes were planted in a randomized complete block design with four replications. The second ratoon crop was evaluated for germination percentage, cane yield, SPAD chlorophyll meter reading (SCMR), chlorophyll fluorescence, relative water content (RWC), specific leaf area (SLA) and stomatal conductance. Root length density (RLD) was evaluated by auger method. The root samples were divided into upper soil layer and lowers soil layers to study root distribution patterns. Sugarcane genotypes were significantly different for RLD, germination percentage and cane yield. Root distribution patterns were classified into three groups based on the RLD. High RLD between plants in the upper soil layers at 90 DAH was positively correlated with high germination, whereas high RLD between rows in the lower soil layers at 90 and 270 DAH was associated with high cane yield. RWC at 90 DAH and stomatal conductance at 180 DAH were closely related to germination percentage, whereas chlorophyll fluorescence and stomatal conductance at 180 DAH were closely related to cane yield.

scholarly journals Physiological Responses of Intsia bijuga Trees to Drought Stress

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 860A-860
Author(s):  
Thomas E. Marler ◽  
Louann C. Guzman
Keyword(s):  
Carbon Dioxide ◽  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Physiological Responses ◽  
Urban Forestry ◽  
The Sun ◽  
Direct Exposure ◽  
Native Tree ◽  
Leaf Shedding ◽  
Use Efficiency

Intsia bijuga is an important native tree on Guam, and is being promoted as an urban forestry tree. Container-grown I. bijuga trees were subjected to a drying cycle (50% of mean water loss replaced daily) to determine physiological responses to drought. Early to mid-morning gas exchange began to decline compared to well-watered plants on day 12, and quickly declined thereafter. Net CO2 assimilation (A) was close to zero by day 29 and became negative by day 36. Chlorophyll fluorescence of drought-stressed trees was not different from that of well-watered trees on numerous days of measurement throughout the drying cycle. Unlike leaflets of well-watered trees, leaflets of the stressed trees exhibited heliotropic movement to avoid direct exposure to the sun. The stressed trees did not respond with any change in osmotic potential of leaflets following rehydration. Carbon dioxide-use efficiency of stressed trees was reduced to 66% of well-watered trees. The most profound response following rewatering (day 37) was leaf shedding. All trees shed some leaves, and 33% of the trees shed the entire canopy. On the trees that retained some leaves, A returned to that of the control trees by day 13 of recovery.

scholarly journals COMPARATIVE HEAT TOLERANCE AMONG FIVE SPECIES OF BIRCH

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 627d-627
Author(s):  
Thomas G. Ranney
Keyword(s):  
Chlorophyll Fluorescence ◽  
Stomatal Conductance ◽  
Heat Tolerance ◽  
Dark Respiration ◽  
Leaf Gas Exchange ◽  
Betula Papyrifera ◽  
Respiration Rates ◽  
Fluorescence Measurements ◽  
Variable Chlorophyll Fluorescence ◽  
Paper Birch

Leaf gas exchange and chlorophyll fluorescence measurements were used as indices for evaluating heat tolerance among five species of birch: paper (Betula papyrifera), European (B. pendula), Japanese (B. platyphylla var. japonica `Whitespire'), Himalayan (B. jacquemontii), and river (B. nigra). Measurements were conducted on individual leaves at temperatures ranging from 25C to 40C. Carbon exchange rates (CER) were depressed for all species at 40C. However, there was considerable variation in both absolute and relative (percent of maximum) CER among species at 40C; river birch maintained the highest absolute and relative CER while CER of paper birch was reduced the most. Although stomatal conductance of paper birch decreased at higher temperatures, internal leaf CO2 increased indicating that reduced stomatal conductance was not responsible for decreased CER. Stomatal conductance of river birch increased at higher temperatures which provided for enhanced uptake of CO2 and greater evaporative cooling. Variable chlorophyll fluorescence decreased similarly for both species with increasing temperatures. Measurements of dark respiration rates over the range of 25C to 40C suggested that the primary factor influencing variation in CER at higher temperatures was due to variation in respiration rates at higher temperatures.

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