The influence of water stress on the growth and development of Townsville stylo (Stylosanthes humilis) in pure ungrazed swards at Katherine, Northern Territory

1977 ◽  
Vol 17 (87) ◽  
pp. 598 ◽  
Author(s):  
MJ Fisher ◽  
NA Campbell
Keyword(s):  
Water Stress ◽  
The Other ◽  
Stylosanthes Humilis ◽  
Relative Water ◽  
Influence Of Water ◽  
Leaf Relative Water Content ◽  
Final Yield ◽  
Townsville Stylo ◽  
Effect On Yield

In order to understand more fully the effect of water stress on the growth of Townsville stylo (Stylosanthes humilis) (TS), five drought treatments, imposed by the use of rain shelters, were compared with an unstressed control in a field experiment. Droughts were imposed during the early vegetative (EV) and late vegetative (LV) stages, and during flowering (F) until leaf relative water content at 2.30 p.m fell to 60 per cent. Further unrelieved drought was re-applied to these three treatments when seeding was well advanced. The other two treatments were subjected to unrelieved drought, one starting at late flowering (LF) and the other seeding (S). The drought treatments had no effect on the final yield of dry matter compared with the control. Stress during the vegetative stage reduced growth, but the relief of stress was followed by a period of rapid growth which largely compensated for the loss. However, because the EV stress killed 40 per cent of the sward (the plants were unable to use water from depths below 75-1 00 cm), the compensatory phase in this treatment was less marked, but more sustained. Because of the decline in growth rate with approaching maturity, stresses during and after flowering had little effect on yield. Stress during vegetative growth hastened flowering by two weeks; however, pod yields were only reduced in the LF treatment. In general these observations demonstrate important aspects of the plants' good adaptation to the dry monsoonal tropics, and explain its stable long-term yields when maintained in near-pure swards.

The influence of water stress on nitrogen and phosphorus uptake and concentrations in Townsville stylo (Stylosanthes humilis)

1980 ◽  
Vol 20 (103) ◽  
pp. 175 ◽  
Author(s):  
MJ Fisher
Keyword(s):  
Water Stress ◽  
Phosphorus Uptake ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
Growth Stresses ◽  
Stylosanthes Humilis ◽  
Influence Of Water ◽  
Nitrogen Concentrations ◽  
Townsville Stylo ◽  
Nitrogen And Phosphorus Uptake

The phosphorus concentrations of Townsville stylo (TS) grown in the Northern Territory are lower than in Queensland, and fall below the requirements of grazing cattle for much of the year. An explanation was sought by measuring N and P in swards subjected to water stress at various times during growth. Stresses during early vegetative (EV), late vegetative (LV) and flowering (F) stages were compared with a well watered control. While nitrogen concentrations were affected little, water stress greatly reduced phosphorus concentrations, the relative effects being EV > LV > F. The EV stress depressed phosphorus concentration to 0.08% compared with 0.20% in the control. Phosphorus level recovered on the relief of stress to the same level as the control. Phosphorus concentration in stems was more sensitive to stress than that in leaves. These results show that if chemical analysis of plants is to be used to indicate the phosphorus status of the soil, the analyses will be unreliable unless the plants have grown without water stress for at least six weeks.

scholarly journals DIVERSE STRATEGIES OF RHODODENDRON (Rhododendron sp.) GENOTYPES IN THE WATER SHORTAGE MANAGEMENT

2020 ◽  
Vol 19 (3) ◽  
pp. 159-165
Author(s):  
Peter Ferus ◽  
Dominika Bošiaková ◽  
Jana Konôpková ◽  
Peter Hoťka
Keyword(s):  
Climate Change ◽  
Drought Resistance ◽  
Water Shortage ◽  
Proline Accumulation ◽  
The Other ◽  
Summer Drought ◽  
Free Proline ◽  
Resistance Strategies ◽  
Relative Water ◽  
Leaf Relative Water Content

Rhododendrons in numerous gardens in Central Europe are frequently endangered by adverse summer drought periods associated with the climate change. Therefore, in this work drought-resistance strategies in recent genotypes of these highly aesthetic shrubs were investigated. Dehydrated Rhododendron groenlandicum ‘Helma’, R. obtusum ‘Michiko’ and R. hybridum ‘Polarnacht’ showed high initial stomatal conductances (gS), after few days steeply falling to the stable minimum at ca. 20, 85 and 70% leaf relative water content (RWC), respectively. Except of ‘Polarnacht’, they had relatively large specific leaf area and ‘Michiko’ also free proline accumulation. On the other hand, R. repens ‘Scarlet Wonder’ and R. hybridum ‘Red Jack’ started with half gS values, continuously declining 1.5–2 fold longer compared to the first group of genotypes (RWC of ca. 60 and 75%, respectively). Both produced relatively thick leaves but did not show any osmotic adjustment. Among observed drought-resistance strategies, lower and longer period active transpiration with stomata sensitive to the water loss, as found in R. repens ‘Scarlet Wonder’ and R. × hybridum ‘Red Jack’, were accepted as the most effective for drought-affected rhododendron plantations.

scholarly journals Photosynthetic acclamatory response of Panicum antidotale Retz. populations to root zone desiccation stress

2024 ◽  
Vol 84 ◽  
Author(s):  
M. Javed ◽  
M. Iqbal ◽  
H. Bano ◽  
N. Hussain ◽  
A. Ghaffar ◽  
...  
Keyword(s):  
Water Stress ◽  
Stress Condition ◽  
Root Zone ◽  
Psii Activity ◽  
Cholistan Desert ◽  
Water Stress Condition ◽  
Relative Water ◽  
Mda Content ◽  
Leaf Relative Water Content ◽  
Panicum Antidotale

Abstract Growth of plants is severely reduced due to water stress by affecting photosynthesis including photosystem II (PSII) activity and electron transport. This study emphasised on comparative and priority targeted changes in PSII activity due to progressive drought in seven populations of Panicum antidotale (P. antidotale) collected from Cholistan Desert and non-Cholistan regions. Tillers of equal growth of seven populations of P. antidotale grown in plastic pots filled with soil were subjected progressive drought by withholding water irrigation for three weeks. Progressive drought reduced the soil moisture content, leaf relative water content, photosynthetic pigments and fresh and dry biomass of shoots in all seven populations. Populations from Dingarh Fort, Dingarh Grassland and Haiderwali had higher growth than those of other populations. Cholistani populations especially in Dingarh Grassland and Haiderwali had greater ability of osmotic adjustment as reflected by osmotic potential and greater accumulation of total soluble proteins. Maximum H2O2 under water stress was observed in populations from Muzaffargarh and Khanewal but these were intermediate in MDA content. Under water stress, populations from Muzaffargarh and Dingarh Fort had greater K+ accumulation in their leaves. During progressive drought, non-Cholistani populations showed complete leaf rolling after 23 days of drought, and these populations could not withstand with more water stress condition while Cholistani populations tolerated more water stress condition for 31 days. Moreover, progressive drought caused PSII damages after 19 days and it became severe after 23 days in non-Cholistani populations of P. antidotale than in Cholistani populations.

Management options for increasing the productivity of tropical savanna pastures. IV. Population biology of introduced Stylosanthes spp

1989 ◽  
Vol 40 (6) ◽  
pp. 1227 ◽  
Author(s):  
JJ Mott ◽  
WH Winter ◽  
RW McLean
Keyword(s):  
Population Biology ◽  
Large Scale ◽  
Rapid Decline ◽  
Management Options ◽  
Hard Seed ◽  
Long Term Stability ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
Fertilizer Rates

In a large-scale grazing experiment in the Monsoon Tallgrass savannas of the Northern Territory, Townsville stylo (Stylosanthes humilis), Caribbean stylo (S. hamata) and perennial stylo (S. scabra + S. viscosa) were sown into native pasture and grazed at three stocking rates, under two fertilizer rates and with trees killed and unkilled. These treatments, together with the occurrence of anthracnose, led to the rapid decline in both yield and numbers of plants in those pastures sown to Townsville stylo. In contrast, yields of Caribbean stylo and Perennial stylo stabilized after three years in both fertilized and unfertilized swards. While total legume yield of these latter two treatments was similar, the dominant contribution in Caribbean stylo was made by annual plants, while in Perennial stylo swards individuals more than 18 months old contributed 80% of the yield.There were marked differences between all species in their population biology. Townsville stylo declined in numbers with death of individuals prior to seed set and the rapid depletion of the soil seed pool which had little long-lived seed. In contrast, in swards of Caribbean stylo a large amount of hard seed rapidly built up in the soil seed pool and ensured continuity of productivity even if seed was not set in some years. In the perennial stylos, seed softened quickly, and the soil seed pool remained small and short-lived. In these latter Stylosanthes spp., long-term stability depended on the survival of perennating plants rather than seed.Pasture management must take into account these different patterns of population dynamics. In particular, while fire is a potentially useful tool in renovating Caribbean stylo swards with their large soil seed pool, it can be extremely detrimental to perennial stylo swards where individuals are susceptible to burning and there is little soil seed available to re-establish the sward.

scholarly journals Induced Genetic Variations in Stomatal Density and Size of Rice Strongly Affect Water-Use Efficiency, Drought Tolerance, and Responses to Abiotic Stresses

2021 ◽  
Author(s):  
Mutiara K. Pitaloka ◽  
Robert S. Caine ◽  
Christopher Hepworth ◽  
Emily L. Harrison ◽  
Jen Sloan ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Treatment ◽  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
The Other ◽  
Low Density ◽  
Stomata Density ◽  
Use Efficiency

Abstract BackgroundRice (Oryza sativa) is one of the world’s most important crops and is especially important in Asia. Because irrigated rice consumes about 34–43% of the total water used for irrigation globally, increasing drought and global temperature will increase the risk of rice crop loss. However, rice is among the least efficient crops in terms of water use, whereby most of the uptaken water is used for transpirational cooling via stomatal pores on the leaf blades and sheaths. To increase the water-use efficiency of rice, alterations in stomatal density and size may help to reduce transpiration and thereby increase water-use efficiency (WUE). ResultsWe identified four stomatal model lines—with either high-density (HD) or low-density (LD) stomata and small-sized (SS) or big-sized (BS) stomata—from the Mutant Core Collection (MCC) of 216 mutants. Gas exchange analysis revealed that the stomatal model lines have similar photosynthetic assimilation (A) and chlorophyll fluorescence. With increasing CO2 concentration, A of all stomatal model lines was observed to respond similarly at 100–600 ppm CO2, but beyond this point, SS was more responsive to increasing CO2 concentration than the other stomatal model lines. HD had higher stomatal conductance (gs) and gsmax than the other stomatal model lines. In response to a mild heat at 30 °C, both SS and LD had higher canopy temperature than HD, BS, and JHN-wt as a result of heat retention. All stomatal model lines are also similar in their rhythmic stomatal responses to ten-minute dark/light transition cycles, except that initial stomata closure in SS was more rapid than in BS. The stomatal model lines did not show any significant differences in the response to short-term water stress. Long-term water stress had less impact on leaf drying, Fv/Fm, grain yield, and harvest index in LD and SS. In the field, all stomatal model lines and JHN-wt had similar WUE in the sufficient-water treatment. LD had the highest WUE and biomass/plant than any stomatal model lines in the long-term restricted-water treatment. ConclusionsTaken together, our results suggest that induced alterations in stomata density and size influence rice WUE and the responses to drought and heat stresses, providing further understanding of the roles of stomata density and size in related processes. The low-density and small stomata lines have high potential as genetic donors for improving WUE and drought in climate-ready rice.

scholarly journals Osmotic and Turgor Adjustment in Rosa Foliage Drought-stressed under Varying Irradiance

1990 ◽  
Vol 115 (4) ◽  
pp. 661-667 ◽  
Author(s):  
Robert M. Augé ◽  
Ann J.W. Stodola ◽  
Brian D. Pennell
Keyword(s):  
Soil Moisture ◽  
Elastic Modulus ◽  
Water Stress ◽  
Relative Water Content ◽  
The Other ◽  
Ambient Light ◽  
Moisture Treatment ◽  
Relative Water ◽  
Osmotic Potentials ◽  
Water Contents

The influence of irradiance and drought on osmotic and turgor adjustment was examined in leaves of rose (Rosa hybrida L. `Samantha'). Plants cultured under full ambient light in the greenhouse were placed in shade chambers and, after 2 weeks of acclimation, exposed to drought for 21 days. Treatments consisted of a water stress factor (well-watered and drought-stressed) and an irradiance factor (100%, 70%, and 30% of ambient irradiance). Pressure-volume analyses of leaves indicated that osmotic potentials at full turgor were decreased 0.42, 0.36, and 0.23 MPa by drought in the 100%, 70%, and 30% irradiance treatments, respectively. Plants stressed under 100% and 70% irradiance exhibited similar osmotic adjustments. Plants under 30% irradiance had higher osmotic potentials at full turgor under well-watered conditions than plants in the other two irradiance treatments and showed only 55% as much adjustment to drought. In each irradiance treatment, drought induced an increase in elastic modulus and a decrease in relative water content at zero turgor. Turgor pressures were higher across a range of relative water contents in plants in the two higher irradiance treatments under both soil moisture treatments. Turgor also was higher at any particular water potential at 100% and 70% irradiance than 30% irradiance, within each soil moisture treatment. Heavy, but not mild, shading inhibited osmotic and turgor adjustments in leaves during drought.

The control of grass weeds in Townsville stylo (Stylosanthes humilis) experiments

1970 ◽  
Vol 10 (47) ◽  
pp. 795
Author(s):  
MJ Fisher ◽  
JR Ive
Keyword(s):  
Annual Grass ◽  
Stylosanthes Humilis ◽  
Weed Seeds ◽  
Heavy Burden ◽  
Excellent Control ◽  
Townsville Stylo ◽  
Grass Weed

Chlorthal applied at 4 lb a.i. an acre before simulated germinating rain gave excellent control of annual grass weeds in an old Townsville stylo (Stylosanthes humilis) sward carrying a heavy burden of grass weed seeds at Katherine, N.T. The technique was used successfully to control annual grass weeds in a long-term residual phosphate experiment. Trifluralin and dalapon were not effective.

scholarly journals The Effect of Water Stress on Some Morphological, Physiological, and Biochemical Characteristics and Bud Success on Apple and Quince Rootstocks

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ibrahim Bolat ◽  
Murat Dikilitas ◽  
Sezai Ercisli ◽  
Ali Ikinci ◽  
Tahsin Tonkaz
Keyword(s):  
Water Stress ◽  
Shoot Length ◽  
Biochemical Characteristics ◽  
Stress Control ◽  
Physiological And Biochemical Characteristics ◽  
Relative Water ◽  
Leaf Relative Water Content ◽  
The Impact ◽  
Santa Maria ◽  
Physiological And Biochemical

The effects of different water stress (control, medium, and severe) on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67%) and Santa Maria/MA (70.33% and 15.33%) combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present.

Stomatal and physiological response of contrasting Z. mauritiana (Lamk.) clones to water stress

2016 ◽  
Author(s):  
M. Kulkarni
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Stress Tolerance ◽  
Fruit Production ◽  
Relative Increase ◽  
Leaf Temperature ◽  
Fruit Drop ◽  
Water Stress Tolerance ◽  
Relative Water ◽  
Leaf Relative Water Content

AbstractWater stress is one of the major limitations to fruit production worldwide. Identifying suitable indicators, screening techniques and quantifiable traits would facilitate the genetic improvement process for water stress tolerance. In the present study, we evaluated the ability of physiological parameters (Transpiration, E; Fv/Fm; leaf water potential, ψleaf; leaf temperature, LT; and, leaf relative water content, RWC) to distinguish between contrasting Z. mauritiana clones subjected to a 30-d drought cycle. Four field-grown clones Seb and Gola (tetraploid) and Q 29 and B 5/4 (diploid) were studied. By 30 d after the onset of water stress treatment, the E, Fv/Fm, ψleaf and RWC of drought-stressed plants had declined significantly in all genotypes compared to values of well-watered treatments. However, the reductions were more severe in leaves of diploid clones. Under drought stress, the Seb and Gola, maintained higher E (31.5%), Fv/Fm (6.28%), ψleaf; (11.2%), and RWC (9.3 %) than Q 29 and B 5/4 clones. In general, LT of drought-stressed plants was higher (~4°C) than that of well-watered plants but the relative increase was greater among later than former ones. Under maximum drought stress, LT of Seb and Gola clones was on average 3.0°C lower than that of Q 29 and B 5/4. Former clones yielded 20% more than later ones, mainly reason being (14.8%) less fruit drop as an effect of water stress. The results indicate that presented parameters can be reliable in screening for water stress tolerance ability, with Fv/Fm, ψleaf, RWC and LT having the added advantage of being easily and quickly assessed.

Drought resistance at the seedling stage in the promising fodder plant tedera (Bituminaria bituminosa var. albomarginata)

2012 ◽  
Vol 63 (10) ◽  
pp. 1034 ◽  
Author(s):  
Kevin Foster ◽  
Megan H. Ryan ◽  
Daniel Real ◽  
Padmaja Ramankutty ◽  
Hans Lambers
Keyword(s):  
Water Stress ◽  
Drought Resistance ◽  
Citrullus Lanatus ◽  
Rooting Depth ◽  
Reconstructed Field ◽  
Bituminaria Bituminosa ◽  
Relative Water ◽  
Leaf Movements ◽  
Leaf Relative Water Content ◽  
Perennial Legume

The perennial legume Bituminaria bituminosa (L.) C.H. Stirt. var. albomarginata (tedera) has been identified as a promising fodder plant for the southern Australian wheatbelt, but little is known about its drought resistance as a seedling. This study was conducted to (i) examine physiological and morphological responses to water stress of seedlings of tedera, in comparison with lucerne (Medicago sativa L.), biserrula (Biserrula pelecinus L.) and Afghan melon (Citrullus lanatus Thunb.), and (ii) investigate drought adaptation mechanisms of tedera seedlings. Seedlings were grown in a reconstructed field soil profile in pots in a glasshouse. By 25 days after sowing (DAS), plants of all species in the drought-stressed (DS) treatment had experienced water stress, with an average leaf relative water content (RWC) of 66% in DS compared with 79% in well-watered (WW) plants. Tedera, biserrula and Afghan melon maintained a higher RWC than lucerne. At 25 DAS, reductions in shoot dry matter in the DS treatment differed between species: 52% for Afghan melon, 36% for biserrula, 27% for lucerne, and no significant reduction for tedera. Paraheliotropic leaf angles of biserrula, lucerne and tedera were all higher in the DS treatment than in the WW treatment at 25, 32 and 52 DAS. This study revealed significant differences in rooting depth and stomatal conductance between the three legume species when under water stress, with tedera being the most drought-resistant. Traits that may allow tedera to survive a dry period following opening rains include vigorous seedling growth, early taproot elongation, effective stomatal control and paraheliotropic leaf movements.

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