Effect Of Soil Moisture Stress Research Articles

Comparative Effects of Soil Moisture Stress and Restricted Root Zone Volume on Morphogenetic and Physiological Responses of Soybean [Glycine max(L.) Merr.

Comparative Effects of Soil Moisture Stress and Restricted Root Zone Volume on Morphogenetic and Physiological Responses of Soybean [<i>Glycine max</i>(L.) Merr.

EFFECT OF SOIL MOISTURE AND FERTILIZER ON THE POTENTIAL AND ACTUAL YIELD OF LOWBUSH BLUEBERRIES

Lowbush blueberry (Vaccinium angustifolium Ait.) plants were evaluated under greenhouse and field conditions to determine the effect of soil moisture stress and fertilizer applied during the year of bud formation on plant growth and development. Greenhouse plants grown under water treatments of 0.2 (about field capacity), 0.6, 1.0 and 5.0 bars did not differ significantly in number of stems per plant or flower buds per stem. A significant increase in the number of flowers per stem was detected for the 0.2- and 0.6-bar treatments over the 1.0- and 5.0-bar treatments. A highly significant trend was an increase in flowers per plant related to an increase in water application. Established field plants had no significant difference in the number of flowers between the unirrigated control and the 0.6- or 0.2-bar treatments. The number and total weight of berries increased significantly with increased water availability during the vegetative growth year but individual berry size remained the same. Irrigation during the year of bud formation may result in increased yield during the crop year. No significant fertilizer application effect was detected on the parameters evaluated.Key words: Vaccinium angustifolium, flower buds

The Effect of Soil Moisture Stress to Various Fractions of the Root System on Transpiration, Photosynthesis, and Internal Water Relations of Peach Seedlings1

Abstract Peach [Prunus persica (L.) Batsch] seedlings were grown in large sectional boxes with root systems divided into 4 separate quadrants. Groups of peach seedlings with 3, 2, 1, and 0 quadrants of the root system deprived of water for 3 weeks, were further subjected to moisture stress in all quadrants by withholding water for 5 days, and they were then rewatered. In another treatment, seedlings were subjected to 2 cycles of water stress, applied 3 weeks apart, by completely depriving all quadrants of water until the plants wilted. Transpiration, photosynthesis, stomatal conductance, and xylem pressure potential were measured. Subjecting a large portion of the root (50%) to stress by withholding water only caused a small reduction (17%) in transpiration, photosynthesis, and stomatal conductance. Subjection of various fractions of the root system to severe moisture stress did not affect the shoot:root ratio. The reduction in root growth in dry quadrants was accompanied by the production of more roots in wet quadrants and less transpiring leaf surface and branch growth. The rate of recovery of transpiration and photosynthesis from water stress was greatly influenced by the duration and intensity of wilting as well as by the rate of regeneration of new root systems.

Effect of soil moisture stress on legume-rhizobium symbiosis in soybeans

In a pot culture experiment, the influence of soil moisture stress at different physiological stages of soybean, cv. Hark, on nodulation, symbiosis and nitrogen accumulation was studied. Moisture stress reduced leghemoglobin content of root nodules and nitrogen uptake by plants. It had no effect on number of bacteroids. Stress at mid bloom and rapid pod filling stages reduced yield and seed protein content. However, these parameters were not affected by stress at nodule initiation and early flowering stages, though, flower initiation and maturity of the plant were delayed. Moisture stress at any stage did not alter nitrogen status of roots.

Effect of soil moisture stress on yield, nodulation and nitrogenase activity ofMacroptilium atropurpureum cv. Siratro andDesmodium intortum cv. Greenleaf

The effect of soil moisture stress on growth, nodulation and nitrogenase activity of two tropical forage legumes,Macroptilium atropurpureum cv. Siratro andDesmodium intortum cv. Greenleaf was studied in a pot experiment. After ten weeks growth, the highest moisture stress (20 per cent water holding capacity) significantly reduced only the top weight of both plants. Moisture stress progressively retarded top growth in the two legumes. Similar trends were also observed in defoliated plants. Moisture stress had little or no effect on the nodulation or nitrogenase activity of the plants.

Screening Soybeans for Drought Resistance. I. Growth Chamber Procedure1

The effects of soil moisture stress on root (RWP) and shoot (SWP) water potential, leaf lamina surface area (LSA) and dry weight (LDW), and photosynthesis (PIA) were studied in 21 to 22‐day‐old potted soybean (Glycine max (L.) Merr.) seedlings. Twenty cultivars were studied in an effort to detect differential response patterns to soil moisture stress. Analysis of the pooled data revealed a significant decline for all variables measured with increasing soil moisture stress. However, significant cultivar ✕ soil moisture treatment interaction exists for all variables measured, indicating variation in cultivar response patterns to decreasing soil moisture. Cultivars were classified as drought resistant, intermediate or susceptible for each variable based on individual performance relative to average seedling response to soil moisture stress. An overall estimate of drought performance was made for each cultivar. The results suggest that soybean seedlings differ in drought response. However, cultivars were not consistently classified by the several variables measured. This suggests that assessment of cultivar drought response should be based on observations of a combination of characteristics. Comparison of the results of this procedure to those of an independent field study suggest the desirability of further testing of the material in the field.

Physiological response of dwarf wheat to chlorocholinechloride under soil moisture stress

Spraying of CCC (500 ppm) on wheat cv. Kalyan Sona-227 averted the adverse effect of soil moisture stress at the anthesis phase, by maintaining a higher level of chlorophyll, nucleic acids and protein content and acidity of the tissues. Treated plants after recovery from moisture stress yield even more than the untreated plants.

Effects of soil moisture stress on monoterpenes in loblolly pine

Monoterpene composition of xylem oleoresin in pole-size loblolly pine (Pinus taeda L.) was different between moisture-stressed and -unstressed trees during two test years. α-Pinene concentration increased in stressed trees whereas β-pinene, myrcene, and limonene decreased. Variations in camphene concentration with soil moisture stress were inconclusive. It increased with moisture stress in one test year and decreased in stressed trees during the other test year.

Effects of Soil Moisture Stress on Xylem Sap Pressure and Relative Water Content of Abies and Picea Seedlings

Effects of Soil Moisture Stress on Xylem Sap Pressure and Relative Water Content of <i>Abies</i> and <i>Picea</i> Seedlings

The Effect of Soil Moisture Stress on Photosynthesis, Transpiration and Leaf Enlargement in Some Kenyan Vegetable Plants

The Effect of Soil Moisture Stress on Photosynthesis, Transpiration and Leaf Enlargement in Some Kenyan Vegetable Plants

Phosphorus Uptake by Soybeans as Influenced by Moisture Stress in the Fertilized Zone1

AbstractReports on the effect of soil moisture stress on plant uptake of P have been conflicting. The effect of the dynamic variation in soil moisture on P uptake by soybeans (Glyfine max L. Merr.) was studied in vivo. A split‐root technique with plants grown in 3 liter containers in the greenhouse was used whereby moisture stress was localized in the zone having the only source of P for the roots, while water and P‐free nutrients were supplied through the other portion of the root system. The procedure minimized the effect of plant‐water deficit.Differences between moisture treatments accounted for 81.5% of plant P content when the effects of fertilizer treatments were removed, while variation in soil moisture content within each moisture treatment accounted for only 8%. The extent P uptake was impaired by high moisture stress was conditioned by the P status of the plant which in turn was determined by the previous soil moisture history of the zone supplying the P. After watering, plants exposed to a high moisture stress resumed P uptake at a rate exceeding that of plants absorbing P from the adequately watered compartment.The range of response to which increasing levels of fertilizer P was obtained increased as the period of moisture stress in the fertilized zone was prolonged. Temporary luxury consumption of P, induced by high levels of soil P and foliar application, benefited soybeans whose P supply was curtailed by high moisture stress.Moisture stress appeared to affect P uptake largely through its influence on diffusion rather than mass‐flow. It is suggested that the inconsistencies of field results reported in the literature studying the relationship of P uptake and moisture stress could be caused by the peculiar P uptake behavior found in these experiments.

The effect of moisture stress upon the hatching of Nematodirus battus larvae.

An experiment was carried out to investigate the effect of soil moisture stress upon the hatching behaviour of Nematodirus battus. The method involved the use of polyethylene glycol solutions to maintain a steady osmotic pressure around a soil containing N. battus eggs, which were ready to hatch. Different concentrations of polyethylene glycol (creating different moisture stresses) were found to affect the numbers and the rate of egg hatching markedly.

Stomatal Movement and Water Relations in Crops : 3. Behavior of stomata and transpiration in tobacco plant during and after drought with the aid of recording apparatus

Qualitative changes in apparent stomatal aperture and transpiration rate of two potted tobacco plants (Nicotiana tabacum L. var. Bright Yellow) after topping were simultaneously measured with porometers and balances by which continuous recording were enabled (fig. 1). The experiment was conducted in the growth cabinet under the conditions of the illumination of 8800 lux from 9.00 a.m. to 5.00 p.m. and of other meteorological factors as mentioned in fig. 2. One plant was stopped watering during 12 successive days and, after severe wilting, rewatered sufficiently. Another plant was well watered every day to compensate the transpiration. 1. Each datum was compared between two plants, and the effect of soil moisture stress on stomatal opening and rate of transpiration are indicated in fig. 3. In the developing process of water stress, the stomatal opening began to decrease at pF 2.7, but the rate of transpiration began to decrease at about pF 3.4. Therefore, it was made clear that the stomatal function is more sensitive to the water shortage. 2. When water stress increased to pF 4.0, the distinct closing of stomata accompanied by transpiration depression was perceived even in the dark (fig. 3). Such a small change of aperture of stomata was easily detected by the recording porometer method but not by the infiltration method. 3. There exists a curvilinear relationship between stomatal opening and transpiration rate in the light, but it was obscure in the dark (fig. 4). A marked difference in these two curves of transpiration is caused by the existence or absence of illumination. The curve in the light indicates that the smaller the aperture operates the higher the degree of stomatal control of transpiration is. At the time when the plant is wilted and its stomatal aperture is small, actual transpiration rate shows a large depression as compared with Bange (1953)'s theoretical curve obtained by leaf disk method. Such depression may be caused by the reduction of leaf area and the change of leaf form in intact plant. The transpiration rates of recovery processes after rewatering (in dotted lines) are evidently lower than those before wilting both in the light and in the dark. 4. After rewatering, the wilted tobacco plant quickly regained its normal turgesence in external appearance. However, the recovery of full stomatal function required four days and transpiration rate did not recover enough during four days owing to the after-effect of severe wilting.

Internal Leaf Water Status and Transport of Water in Rice Plants1

AbstractRice (Oryza sativa L.) is generally grown continuously submerged in lowland soils and under rainfed conditions in upland soils. The objective of this study was to relate transpiration rate and leaf water potential to relative water content. This information may be useful in predicting the effect of soil moisture stress on growth and yield.Rice variety ‘IR‐8’ was grown in the greenhouse for 50 to 60 days under submergence and N⅓ bar soil matric potential, and then allowed to wilt.The pressure potential of leaves approached zero at a total water potential of about −19.5 bars, corresponding to 0.33 relative water content. Leaves experienced a change in cell elasticity at about 3 bars pressure potential and −10 bars total water potentialTranspiration rate decreased with leaf water potential, but it was independent of depletion of soil moisture content above 0.21 and 0.18 for plants grown in submerged and unsaturated soil conditions, respectively. These moisture contents correspond to −0.8 bar and −2.0 bars matric potential. Further depletion in moisture content of both soil moisture regimes resulted in a marked decrease in leaf water potential and in transpiration. Trans. port of water in the rice soil‐plant system was affected more by plant factors under flooded conditions than under unsaturated soil conditions.

Yield Response of Soybean Varieties Grown at Two Soil Moisture Stress Levels1

AbstractEight soybean [Glycine max (L.) Merrill] varieties in each of four maturity groups were grown to maturity at optimum and deficient soil moisture conditions to determine differences in varietal response to soil stress. A significant variety by stress level interaction on seed yield was detected among varieties in each of four maturity groups, indicating that the effect of soil moisture stress on yield varied among varieties.Under high moisture stress conditions, the yield of the most stress resistant varieties was reduced about 20%, while the yield of the least stress‐resistant varieties was reduced about 40%. The absolute reduction in yield for the most stress‐sensitive varieties was approximately 1000 kg/ha, while the yield of the least stress‐sensitive varieties was reduced about 200 to 400 kg/ha.Under conditions of optimum soil moisture, the difference in yield among varieties was large relative to the difference in yield produced under deficient moisture conditions. A low or nonstress soil moisture level permits greater genotypic expression, thereby increasing genotypic variance among varieties. A low soil moisture stress environment appears to be the optimum environment for selecting soybean yield attributes.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel IV. Effects of Periods of Stress Occurrence, Correlations and Regressions

SUMMARYEffects of moisture stress during different stages of cotton development were evaluated by using correlation and regression methods on data of six irrigation experiments from three different climatic regions. Significant negative correlations were found between the number of days in which soil moisture was below a threshold level, and several plant traits. Flower number was usually affected adversely by stress at the beginning of flowering; boll number, boll retention, boll weight, lint yield, lint length and seed index by stress at the end of flowering; earliness and lint fineness by stress during early boll development. Lint index, per cent and strength were affected by stress at different periods and effects of stress on lint yield were correlated with its effects on boll number, boll weight, lint length and early maturity.

Stomatal Movement and Water Relations in Crops : 2. Stomatal behavior of tobacco leaves of different ages and the influence of soil water shortage

Diurnal stomatal behaviors were studied in three leaves (an upper immature, a middle immature, and a lower mature leaves) of a potted tobacco plant under green house condition using recording porometers, during three days. The effect of soil moisture stress (pF) upon stomatal behavior was also examined. 1. Every morning, pre-dawn opening was observed evidently in the upper and middle immature leaves, but hardly seen in the lower mature leaf (fig. 1). 2. The stomatal opening markedly increased in every leaf with increasing light intensity after sunrise even under high soil moisture stress (fig. 1). 3. The time of peak in the stomatal opening appeared earlier as the leaf became older. In the case of the immature leaf, the same phenomenon was seen under highest pF condition (table 1). These peaks showed sharped shape by the shortening of their width (opening period) due to the occurrence of remarkable midday closure (fig. 1). 4. The lower mature leaf showed severe midday closure of stomata at high light intensity even under mild soil moisture stress pF 3.10, but the upper immature leaf scarcely showed midday closure. 5. Soil moisture stress increment promoted the development of midday closure in depth and length in every leaf, especialy in the upper and middle immature leaves (table 2). 6. Averaged stomatal opening and opening period decreased with increasing leaf age and soil moisture stress (fig. 2). This resulted from that the leaf water deficit was produced by internal (leaf age) and external (pF) conditions, and that such deficit caused the midday closure and the suppression of reopening of tobacco stomata (table 2). 7. Marked difference was found between forenoon stomatal opening curve and afternoon stomatal closing curve within the middle and lower leaves. 8. The notable photoactive opening (including hydropassive opening) after sunrise and remarkable midday closure (hydroactive closing) under strong solar radiation occurred simultaneously in the tobacco stomata in three leaves. Such synchronism suggests that these both stomatal behaviors were associated with the variation of xylem hydraulic tension.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel. III. The Bet-She'an Valley

SUMMARYThe effects of moisture stress during various stages of the development of two varieties of upland cotton (Acala 4–42 and Deltapine Smoothleaf) were studied in two irrigation experiments in the Bet-She'an valley, where summer temperatures were high and evapotranspiration in the fully irrigated treatments was up to 8–10 mm./day in July and August. Optimum time for first irrigation in the Bet-She'an valley was two or three weeks before flowering and six or seven irrigations, if timed to prevent moisture stress, were sufficient to give high yields and good lint quality. Lint yield ranged from 270 kg./ha. in non-irrigated to 2000 kg./ha. in the fully irrigated treatments in 1966.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel II. The Northern Negev Region

SUMMARYThe effects of moisture stress at various stages of development were studied on two varieties of cotton in the arid Negev region of Israel. Experiments over two years indicated that the stage at which moisture stress occurred determined its effect: when at the beginning of flowering, yield was considerably reduced; at the peak of flowering there was a less pronounced effect; and when stress occurred during boll development it had an effect in only one year, when reserves of moisture in the deep soil layers were low. Lint yield ranged from 380 kg./ha. without irrigation to 2150 kg./ha. with five irrigations. Effects on lint length and lint strength were also studied. Two physiological indices, stomatal aperture and refractive index of leaf sap, were used to determine the onset of moisture stress.

Effects of Soil Moisture Stress on Two Varieties of Upland Cotton in Israel I. The Coastal Plain Region

SUMMARYEffects of moisture stress during different stages of cotton development were examined in two experiments when temperatures were mild and evapotranspiration less than 6 mm./day. Two varieties of upland cotton, Acala 4–42 and Deltapine Smoothleaf, were affected similarly. Moisture stress at the beginning of flowering reduced growth rate and the numbers of flowers and bolls. During the second half of the flowering period it reduced the percentage of boll retention, boll number, boll weight, seed index, lint index and lint length. Stress during boll development had similar effects and caused earlier maturity. Lint yield was reduced significantly by moisture stress during each of the periods but tensile strength of lint was not affected. Three irrigations, if properly timed so that no appreciable moisture stress occurred, were sufficient for high yields and good quality of lint, and the first could be postponed until after flowering began without any loss in yield.