Stomatal Diffusive Resistance Research Articles

Evaluation of Sugarcane Varieties Based on Stomatal Behavior Under Water Stress Condition

An experiment was conducted during 2015–2016 to 2017–2018 at UP Council of Sugarcane Research, Shahjahanpur. Ten promising sugarcane varieties, viz. CoS 12232, CoS 14232, CoS 06279, CoS 10231, CoS 13231, Co 0238, CoS 09232, CoS 08276, CoS 08279 and CoSe 01434, were used for the evaluation of drought-tolerant varieties suitable for planting under water stress condition. Two moisture levels, normal (50 ASM) and deficient (20 ASM), were maintained during pre-monsoon period. Stomatal behavior was studied. Results revealed that all the varieties were adversely affected due to deficient moisture level. Under deficient moisture, varieties CoS 12232, CoS 14232 and CoS 06279 expressed higher total chlorophyll. These varieties showed the minimum rate of transpiration along with maximum stomatal diffusive resistance and leaf water potential under water stress. These varieties also showed a significant reduction in shoot height, leaf area of the first open leaf, shoot population, number of millable canes and cane yield (below 10%) under low moisture levels as compared with other tested varieties. Due to water stress, sucrose content was not affected significantly. Conclusively, varieties CoS 12232, CoS 14232 and CoS 06279 were found suitable for planting under deficient moisture condition.

Assessing Greek Bread Wheat Landraces for their Drought Resistance Strategies

The physiological mechanisms activated by 10 bread wheat (Triticum aestivum L.) landraces of Greek origin when facing drought were examined under field conditions during two cultivation seasons in Greece. Ten landraces of bread wheat were cultivated under four different degrees of water stress, induced by means of increasing distances from a drip irrigation line under rainout shelters. A number of morphological and physiological traits associated with water absorption (root surface density, water potential decline between the wettest and driest treatments, and osmotic adjustment) and water loss (stomatal sensitivity and leaf senescence) were monitored on seasonal and diurnal basis. Considerable differences among the landraces were detected for most of the examined traits (root surface density, degree of osmotic adjustment, stomatal sensitivity, and drought‐dependent leaf senescence). A discriminant function analysis using the examined traits revealed landraces and groups of them endowed with different potentialities for absorbing and consuming water. On this account, the landraces were assessed for their abilities to absorb and save water. The sensitivity of the stomatal mechanism, estimated from diurnal fluctuations of stomatal diffusive resistance, was the trait mainly responsible for a clear discrimination of all landraces. Osmotic adjustment was not found to be a mechanism of major importance in the behavior of the majority of the examined landraces under water stress conditions. The conclusions drawn from this kind of physiological approach are discussed in respect to the grain yield sensitivity of the examined germplasm to water shortage. Thus, landraces exhibiting higher potentials for water absorption and water consumption also exhibited higher yield stability under water stress.

Physiological and chemical characteristics of safflower (Carthamus tinctorius L.) grown in the presence of low salt concentrations

(Carthamus tinctorius L.) is highly regarded in the world as an aromatic, spicy, medicinal and oilseed crop, which can be used in all kinds of industries. It inhabits arid and semiarid areas of the world. The influence of the relatively low NaCl concentrations found in soils and irrigation waters on the growth and metabolism of saf?flower, grown under semi-controlled conditions, was examined in this work. It was found that increased concentrations of NaCl affected the number of leaves per plant and dry leaves mass/area ratio. The transpiration intensity was reduced in plants grown in the presence of NaCl and stomatal diffusive resistance increased following an increase in NaCl concentration.

Top Grafting Performance of Some Cocoa (Theobroma cacao L.) Clones as Affected by Scion Budwood Number

Reducing budwood number is an efficient effort to overcome problemsrelated with limited scion materials. The objective of this research was to studythe effect of scion budwood number in some clones on the performance of graftedcocoa seedlings. The research was conducted at Kaliwining Research Station,Indonesian Coffee and Cocoa Research Institute, Jember, Indonesia at an elevationof 48 m above sea level. Layout for this study used factorial with 2 factors inrandomized complete block design, with four replications for every treatment.The first factor was clone type, namely MCC 02 and Sulawesi 1; whereas the secondfactor was number of grafted scion budwood, namely one, two, and three graftedbudwoods. There was no interaction between clone and number of scion budwoodfor variables of shoot length, stem girth, content of total chlorophyll, chlorophylla, and chlorophyll b. Meanwhile, there was interaction for stomatal conductanceand stomatal diffusion resistance. Clone significantly affected photosynthesisand stomatal diffusion resistance, while number of scion budwood affected significantlythe shoot length. Photosynthesis activity of MCC 02 was higher comparedto Sulawesi 1. In average, stomatal diffusion resistance of Sulawesi 1 was higherthan MCC 02. The shoot length of one grafted budwood was higher than thetwo or three grafted budwood.

Stomatal Conductance and Chlorophyll Characteristics and Their Relationship with Yield of Some Cocoa Clones Under Tectona grandis, Leucaena sp., and Cassia surattensis.

An optimum physiological condition will support high yield and quality of cocoa production. The research was aimed to study the effects of stomatal conductance and chlorophyll content related to cocoa production under three shade regimes.This research was conducted in Kaliwining Experimental Station, elevation of 45 m above sea level with D climate type based on Schmidt & Fergusson. Cocoa trees which were planted in 1994 at a spacing of 3 X 3 m were used in the study planted by using split plot design. The shade tree species were teak (Tectona grandis), krete (Cassiasurattensis), and lamtoro (Leucaena sp.) as the main plots, and cocoa clones of Sulawesi 01,Sulawesi 02, KKM 22 and KW 165 as sub plots. This study showed that there was interaction between cocoa clone and shade species for stomatal conductance where stomatal diffusive resistance of KKM 22 was the best under Leucaena sp.and Cassiasurattensis with the values of 1.38 and 1.34 s.cm -1, respectively. The highest chlorophyll content, stomatal index and transpiration values was under Leucaena sp. shade. There was positive correlation between chlorophyll content and transpiration with pod yield of cocoa. The highest yield and the lowest bean count wereobtainedon Sulawesi 01 clone under Leucaenasp. shade.Keywords: stomatal conductance, transpiration, diffusive resistance, shades trees, clones,pod yield

Physiological parameters to select upland rice genotypes for tolerance to water deficit

Abstract: The objective of this work was to evaluate the feasibility of using physiological parameters for water deficit tolerance, as an auxiliary method for selection of upland rice genotypes. Two experiments - with or without water deficit - were carried out in Porangatu, in the state of Goiás, Brazil; the water deficit experiment received about half of irrigation that was applied to the well-watered experiment. Four genotypes with different tolerance levels to water stress were evaluated. The UPLRI 7, B6144F-MR-6-0-0, and IR80312-6-B-3-2-B genotypes, under water stress conditions, during the day, showed lower stomatal diffusive resistance, higher leaf water potential, and lower leaf temperature than the control. These genotypes showed the highest grain yields under water stress conditions, which were 534, 601, and 636 kg ha-1, respectively, and did not differ significantly among them. They also showed lower drought susceptibility index than the other genotypes. 'BRS Soberana' (susceptible control) was totally unproductive under drought conditions. Leaf temperature is a easy-read parameter correlated to plant-water status, viable for selecting rice genotypes for water deficit tolerance.

Growth, physiology, and abiotic stress response to abscisic acid in tomato seedlings

The effect of abscisic acid (ABA) on growth, abiotic stress tolerance, and physiology of tomato seedlings was investigated. To examine the effect of ABA concentration on growth and abiotic stresses, six ABA concentrations (0, 10, 50, 100, 150, or 200 mg·L-1) were applied by foliar spraying once a day for 10 days. The effect of ABA application number was also studied by using different timing at one ABA concentration (100 mg·L-1) once a day for 1, 3, 5, 7, and 9 days. The effect of ABA on physiology of tomato seedlings was examined by using two concentrations (50 and 100 mg·L-1) as compared to the control (non-ABA). Foliar application of ABA decreased the growth characteristics of tomato seedlings in a concentration-dependent manner; however, no statically significant difference was observed between the 50 and 100 mg·L-1 treatments. Furthermore, although growth parameters decreased statistically with increasing number of ABA treatments, there was no difference between the 3 and 5 application treatments. Application of ABA enhanced stress tolerance (cold and drought) of tomato seedlings by delaying the starting time of wilting point in drought conditions and reducing the relative ion leakage and chilling injury index in low temperature in all treatments. The transpiration rate decreased significantly, while stomatal diffusive resistance increased significantly with increasing ABA concentration. The relative water content decreased significantly during the period without irrigation. However, relative water content increased with increasing ABA concentration. The ABA enhanced drought tolerance of tomato seedlings by delaying the start time of wilting point from day 3 in the control to day 5 and 7 in the 50 and 100 mg·L-1 treatments, respectively. Integrating this result data, we can determine the ABA’s ability to maintain of seedling quality at low temperature and water deficit condition.

Effect of Silicate Fertilizer on Growth, Physiology and Abiotic Stress Tolerance of Chinese Cabbage Seedlings

The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.

Influence of Short-term Application of Abscisic Acid in Nutrient Solution on Growth and Drought Tolerance of Tomato Seedlings

This study was conducted to evaluate influence of short-term application of abscisic acid (ABA) in nutrient solution on growth and drought tolerance of tomato seedlings. The treatments included four ABA concentrations (0.5, 1, 2, 3mg·L -1 ) and control (non-treatment) were applied to the nutrient solution in a hydroponic system. On the 5 th and 10 th day after growing in the nutrient solution containing ABA, seedlings were transferred to -5 bars of PEG-8000 in a growth chamber to induce water stress. Except for stem diameter and fresh and dry weight of root, there were no statistical differences in other growth parameters among control, 0.5 and 1mg·L -1 of ABA treatments. Seedlings growths were strongly inhibited in nutrient solution containing 2 and 3mg·L -1 of ABA. The root growth such as fresh and dry weigh of root, total root surface area, and average root diameter was slightly enhanced in 1mg·L -1 of ABA treatment. The elevation of ABA concentrations in nutrient solution resulted in the decrease in transpiration rate and increase in stomatal diffusive resistance and leaf temperature of tomato seedlings. The initiations of seedling wilting after treating in -5 bars of PEG were delayed from 10 hrs in control to 30 hrs in ABA applied treatments. Additionally, the high percentages of recovered seedlings were observed in 0.5 and 1mg·L -1 of ABA treatments after re-irrigation. Therefore, short-term application of 1mg·L -1 of ABA in the nutrient solution stimulated the root growth and drought tolerance of tomato seedlings by delaying the start time of wilting point and enhancing the recovery after re-irrigation.

Impact of Different Water Levels on Growth, Plant Water Relations and Photosynthesis Parameters in Seedling of Tongkat Ali (EURYCOMA LONGIFOLIA JACK)

The effects of water availability on growth, water relations and related plant physiological and biochemical activities of young Tongkat Ali (Eurycoma longifolia jack) plants were investigated. Plant vegetative growth was inhibited with reduced water availability. Leaf water potential and relative water content were reduced with increasing soil water stress. The rate of photosynthesis in Tongkat Ali leaves decreased in response to the stress treatments especially from moderate stress (75%FC), to severe stress (25% FC), compared with the control. Stomatal conductance of Tongkat Ali also steadily decreased with increasing the water stress Due to low water potentials and respectively reduce photosynthesis rate of Tongkat Ali therefore increasing stomatal diffusive resistance in the water deficit led to decline of transpiration rate in young seedling of EURYCOMA LONGIFOLIA JACK.

SCREENING OF SELECTED FOREST TREE SPECIES OF SRI LANKA FOR THEIR RESPONSE TO INCREASING ATMOSPHERIC CARBON DIOXIDE

Investigating the effects of increasing atmospheric CO2 on forest tree species is important asforests playa major role in maintaining the ecological balance of an ecosystem. The objective ofthis study was to determine the response of photosynthesis, and it related physiological parameters,Growth and morphological parameters of selected forest tree species such as Teak (Tectonograndis), J3k (Artocarpus heterophyllusy; Satinwood iChloroxylon swieteniay, and two varieties ofMahogany (Swietenia macrophylla arid Swietenia mahogany) to elevated C02.The experiment was carried out at the Rice Research and Development Institute (RRDI),Batalagoda,lbbagamuwa, from October 2002 to February 2003. Three experimental treatmentswere defined as elevated CO2 (i.e., 570 ppm) in open top chambers, ambient CO2 (i.e., 370 ppm)in open top chambers and ambient C~ (i.e., 370 ppm) under open field conditions. Theexperiment was conducted over a period of 161 days.The total dry weight was higher under elevated C~ as compared to ambient C02 in all speciesexcept Chloroxylon swietenia. The response was highest in Swietenia macrophylla and thehighest mean total dry weight was in the elevated C~ treatment. The mean root dry weight, meanleaf dry weight and mean stem dry weight were significantly higher under elevated CO2 ascompared to the ambient. The height increment during the experimental period was highest inChloroxylon swietenia under elevated C02. The girth increment during this period was highest inSwietenia macrophylla and it was observed in the elevated CO2 treatment. When averaged acrossall species, the mean relative growth rates and absolute growth rates were higher under elevatedCO2 than under ambient. When individual species were considered, only Chloroxylon swieteniashowed a slight decrease in absolute and relative growth rates under elevated C02 while the othersshows an increase. Net photosynthetic rate (Pn) was higher in the elevated CO2 treatment inArtocarpus heterophyllus, Swietenia mahogany and Tectona grandis. But a slight decrease of Pnwas observed in Swietenia macrophylla under elevated C02 in comparison to ambient C02. Leafwater potential was higher in all five species under elevated C02 and the highest response toelevated C~ was observed in Chloroxylon swietenia. The stomatal diffusive resistance washighest in Tectona grandis and the value was 16.86 s em". The lowest was observed inChloroxylon swietenia and the value was 2.87 s em", 'The lowest diffusive resistance wasobserved in the elevated CO2 treatment. The transpiration rate was highest in Chloroxylonswietenia and the value was 12.71~g cm,2 S'l. The lowest was observed in Artocarpusheterophyllus and there was no significant difference among the three treatments. The mean leaftemperature was highest in Artocarpus heterophyllus and the lowest leaf temperature was found inChloroxylon swietenia.Based on the above results, it can be concluded that elevated C(h increases growth of a majority oftree species tested. This could have favourable implications for both natural and plantationforestry in Sri Lanka. Results of the present study showed that the capacity of forests for carbonsequestration would be higher in a future climate with higher atmospheric C02 levels.

Effect of Water Stress on Leaf Temperature, Transpiration Rate, Stomatal Diffusive Resistance and Yield of Banana

The present investigation was undertaken under field condition to study the effect of water deficit on leaf temperature, transpiration rate, stomatal diffusive resistance and yield of banana cultivars and hybrids. Stress was imposed at different critical stages viz., 3 rd , 5 th , 7 th and 9 th month after planting. The stress was given by scheduling irrigation at the 50% available soil moisture (ASM) characteristic during critical stages. The soil moisture content was analyzed by using pressure plate membrane apparatus. In control plots, the irrigation was given at the ASM of 80% with the soil water potential of around - 6 bars and in the case of stressed plots; the irrigation was given when an ASM reached 50% with the soil water potential of - 14 bars. In stressed plots, 50% ASM was reached around 30 days. In this present study conducted with twelve cultivars and hybrids with three replications. The data were analyzed by using split plot design. The research revealed that, leaf temperature was usually negatively correlation with transpiration rate. Transpiration rate revealed a decreasing trend throughout the growth period of the crop with increasing in leaf temperature and stomatal diffusive resistance. The cultivars and hybrids of Karpuravalli, Karpuravalli×Pisang Jajee, Saba, and Sannachenkathali was identified as tolerant to water stress with highly accelerated in transpiration rate by water stress treatment with slight increase in leaf temperature over control.

Studies on Relationships between Ozone Absorption Rate and Stomatal Diffusion Resistance of Plant Leaf

Studies on Relationships between Ozone Absorption Rate and Stomatal Diffusion Resistance of Plant Leaf

Growth, ion composition, and stomatal conductance of peas exposed to salinity

Abstract Availability of irrigation water of appropriate quality is becoming critical in many regions. Excess salt in irrigation water represents a risk for crop yield, crop quality, and soil properties. During the short vegetation period, field peas require high amounts of water, and irrigation is often indispensable for successful production. Steady presence of NaCl (0.1, 0.2, 0.6 or 1.2 g NaCl L−1 in 1/2 strength Hoagland nutrient solution) under semi-controlled conditions reduced growth and resulted in shorter vegetation. Disturbances in the peas’ water regime were provoked by NaCl, as water content in pea tissues was reduced and stomatal density and stomatal diffusive resistance increased in the presence of higher NaCl concentrations. Concentration of Na+ increased in all pea tissues with increased NaCl concentration in the nutrient medium. In the presence of NaCl, concentrations of K+, Ca2+ and Pi increased in roots, stems and leaves, and decreased and in pods and grains. Concentration ratios Na+/K+, Na+/Ca2+, K+/Ca2+ and (Na++K+)/Ca2+ in various plant parts were affected as well, but magnitudes of changes were variable. Continuous presence of NaCl in concentrations frequently met in irrigation waters significantly reduced pea growth, impaired the water regime, and altered plant chemical composition.

Stomatal changes following abscisic acid treatment in several broad‐leaved trees undergoing artificial shade treatment

Changes in the resistance of stomatal transpiration following abscisic acid (ABA) treatment were investigated in four species of broad‐leaved trees that underwent artificial shade treatment. In all four species, Betula platyphylla, Betula schmidtii, Zelkova serrata and Acer mono, the light environment exerted a significant influence on the differences of stomatal transpiration and its changes. The time series changes among the four tree species showed varied tendencies according to the type of treatment and level. In the case of Acer mono, Betula platyphylla and Betula schmidtii, transpiration resistance increased following ABA solution treatment at a low concentration of 0.02 mmol. In addition, the differences were increased according to artificial shade treatment levels and with the passage of time. In the case of Zelkova serrata following ABA treatment at a concentration of 0.05 mmol, seedlings which were developed in a high shade treatment with a back‐light rate of 6% showed a high transpiration resistance of 61.36 s-1/cm at 2 hours after treatment, and it increased greatly with increasing shade intensity and treatment concentration. ABA absorption treatment of the branches indicated the strong effect of shade intensity on stomatal diffusive resistance after processing in an artificial light environment. Therefore, we considered that ABA did not affect the physiological characteristics of the tree species but that the damage was caused by the light environment at the time of measurement. We also determined that light was a factor that had some effect on the increase of transpiration resistance through stomatal closure in the case of the seedlings developed in different light environments.

CHANGES IN THE PHYSIOLOGICAL PERFORMANCE OF LEAF SCORCH DECLINE (LSD) AFFECTED COCONUT (COCOS NUCIFERA) PALMS

Leaf scorch decline (LSD) is a disorder of coconut (Cocos nucifera) palms in Sri Lanka. The etiology of the disorder is not yet known. This study aimed to compare and quantify physiological and biochemical characters of LSD-affected palms with healthy palms. Thirty-year-old apparently healthy and LSD-affected (mild, moderate and severe) palms (variety typica) were compared at Bandirippuwa Estate, Coconut Research Institute, Sri Lanka. In LSD-affected coconut palms, the functional leaf area of the canopy, rates of photosynthesis and transpiration, leaf water potential, leaf chlorophyll and Zn contents were appreciably reduced with the development of the disorder, whereas stomatal diffusive resistances and abscisic acid concentrations in the xylem sap increased. The volume of inflorescence sap collected from LSD-affected palms was reduced compared to healthy palms, but the composition of the sap remained unaltered. Since altered stomatal behaviour might affect gas exchange and related processes, such as water movement, photosynthesis and the assimilate partitioning pattern, these results support the hypothesis that stomatal closure in LSD-affected palms may influence LSD symptoms. However, more research is needed to come up with conclusive evidence of its cause.

Effect of water stress on morpho-physiological traits of sunflower (Hellanthus annus L.) genotypes

An investigation was carried out to study the morphological and physiological mechanisms involved in the differential response of the sunflower genotypes to water stress. Water stress was imposed at early (45 to 60 days after sowing) and late (65 to 80 days after sowing) stages of plant growth. Various morophophysiological parameters viz. plant height, leaf area, leaf expansion rate, RWC, LWP, leaf membrane integrity, stomatal diffusive resistance and transpiration rate were studied. Among the genotypes, TNAUSUF 205, CO 4 and RHA 272 recorded more plant height, leaf area, leaf expansion rate, RWC and LWP and also recorded low leakage of solutes, less transpiration rate with high stomatal diffusive resistance under both the stress situations. This study has demonstrated the interplay of morphological and physiological adjustment that enabled sunflower to survive under conditions of water stress with less reduction in grain yield.

Effect of irrigation management on physiology and productivity of soybean (Glycine max)

A field experiment was carried out during summer and monsoon seasons of max (L.) Merr.] Col with 2 irrigation levels, viz. 1996 using soybean [Glycine 0.40 and 0.60 lW : CPE ratio, 3 methods of irrigation, viz. all furrow, alternate furrow and paired row furrow, and 4 management practices comprising coirpith application, KC1 0.5% at peak flowering stage, Kaolin 3% foliar spray at 30,45 and 65 days after sowing and control. The crop growth and yield were better in monsoon than in summer. Irrigation at 0.60 IW : CPE ratio through all furrow method recorded lower canopy temperature, lower transpiration rate, higher relative leaf water content (RLWC) and stomatal diffusive resistance (SDR) which resulted in higher seed yield. All management practices, viz. coirpith, KC1 and Kaolin, separately maintained higher tissue water content than in the control.

Photosynthesis, chlorophyll fluorescence, and water relations in young sugar beet plants as affected by sulfur supply

The effect of different concentrations of sulfur (1 and 3 mM) and interruption of sulfur (S) supply for 25 days on the photosynthesis and leaf water relations in young sugar beet plants (Beta vulgaris L.) was studied in water culture, under greenhouse conditions. Interruption of S‐supply significantly reduced the content of sulfur, chlorophylls a+b and carotenoids, leaf area, density of stomatal and epidermal cells, transpiration rate and leaf water potential, while it increased the free proline content and stomatal diffusion resistance. An increase in S concentration in the nutrient medium from 1 to 3 mM did not significantly affect the tested parameters, except for an increase in leaf S content and a decrease of leaf water potential. Sulfur deficiency caused a pronounced decrease of the rate and quantum yield of photosynthetic oxygen evolution under non‐photorespiratory conditions. This was partly the result of the diminished photochemical efficiency of photosystem II reaction centers. Less efficient excitation of PSII reaction centers is most probably the consequence of higher thermal energy dissipation in the reaction centers of S‐starved plants. These data support that S nutrition is one of the factors regulating plant photosynthesis.

The influence of waterlogging at different temperatures on penetration depth and porosity of roots and on stomatal diffusive resistance of pea and maize seedlings

The 8 days old seedlings of pea (cv. Ilowiecki) and maize (cv. Alma F1) were subjected to differentiated aeration conditions (control — with pore water tension about 15 kPa and flooded treatment) for 12 days at three soil temperatures (7, 15 and 25 °C). The shoots were grown at 25 °C while the soil temperature was differentiated by keeping the cylinders with the soil in thermostated water bath of the appropriate temperature.