Journal Pre-proof Eco-physiological responses of desert and riverain legume plant species to extreme environmental stress Zainab G. Ahmed, Usama Radwan, Magdi A. El-Sayed PII:
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Biocatalysis and Agricultural Biotechnology
Received Date: 16 March 2019 Revised Date:
4 February 2020
Accepted Date: 5 February 2020
Please cite this article as: Ahmed, Z.G., Radwan, U., El-Sayed, M.A., Eco-physiological responses of desert and riverain legume plant species to extreme environmental stress, Biocatalysis and Agricultural Biotechnology (2020), doi: https://doi.org/10.1016/j.bcab.2020.101531. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier Ltd.
authorship contribution statement Zainab G. Ahmed: Methodology, Investigation, Validation, Writing - original draft. Usama Radwan: IRGA instrument. Magdi El-Sayed, Conceptualization, Data curation, Visualization, Supervision, Writing – review and editing.
Eco-physiological responses of desert and riverain legume plant species to extreme environmental stress
1 2 3
Zainab G. Ahmed, Usama Radwan and Magdi A. El-Sayeda*
Botany Department, Faculty of Sciences, Aswan University, Aswan 81528, Egypt
Unit of Environmental Studies and Development, Aswan University, Aswan 81528, Egypt
*Corresponding authors: M. El-Sayed
E-mail address: [email protected]
Drought and heat events frequency and severity are expected to increase in the near
future as responses to global warming, influencing crops productivity and human diet
as result in the increasing soil aridity and area affected by drought. It is becoming
increasingly important to find new crop plants or genotypes of crops that have
adaptation strategies to water loss at extreme arid conditions. It was hypothesized that
growth and development of plants are affected differently by drought stress, depending
on their nature habitats whether desert or riverain.
In this current research, we
compared the changes in physiological behavior between desert and riverain legume
plants, as response to drought stress at two levels of water regimes. Rates of
transpiration were highly correlated to radiation. Transpiration increases with the
increase in photosynthetic active radiation (PAR) at both levels of water regimes.
Highest photosynthesis (pn) and transpiration (E) were achieved in R. minima at both
low water regime and high PAR (1250). The super oxide dismutase (SOD), catalase
(CAT), phenyl ammonia lyase (PAL) and peroxidase activities were higher in
Rhynchosia minima. Drought stress induced significant accumulation of total sugars,
flavonoids, saponins, proteins and phenolics. The higher photosynthesis rate, higher
flavonoids and phenolics content and stronger activity of protective enzymes were the
important physiological reasons for the drought resistance of Rhynchosia minima.
Keywords: Drought stress, Photosynthesis, R. minima, Lablab purpureus, Antioxidant
enzymes, Transpiration, Chlorophyll fluorescence.
Climatic changes in extreme arid environment were significantly impact on water
availability on agriculture activities (Confalonieri et al., 2007). Drought resistance and
productivity of many crops play an important role in sustainable development of
agricultural activities in arid environments (Shekoofa et al., 2015). Several
environmental challenges such as drought, salinity, heat, flooding and heavy metal
stresses, in single or in combination can affect plants (Kokila et al., 2014).Drought
stress is a common adverse factor affecting plant growth, productivity, and survival.
Physiological and biochemical processes are altered by drought, such as water relation,
gas exchange, photosynthesis and the metabolism of carbohydrates, protein, amino
acids and other organic compounds (Kokila et al., 2014). Studies of (O’toole et al.,
1977) concluded that water stress mediated stomatal closure is generally accepted as
the primary factor associated with decreased net photosynthesis and transpiration.
Another factor that also affecting photosynthesis and related processes is the high
temperature resulted in decreasing viable leaf area and chlorophyll content (Shah and
Paulsen, 2003). In addition, heat stress induces the accumulation of reactive oxygen
species (ROS), leading to the destruction of plant lipids, proteins, and carbohydrates.
Thus, plants have evolved antioxidant defense systems which include non-enzymatic
(flavonoids, ascorbic acid, and glutathione) and enzymatic antioxidants to scavenge
the excess level of ROS and maintain cell ROS homeostasis (Ali et al., 2017). Drought
and high temperature often occur simultaneously. Their effects on plants were studied
individually but combined effect of the interaction between the two stresses deserves
more studies (shah and Paulsen 2003). There have been studies on understanding the
use of chlorophyll fluorescence in plant science. Chlorophyll is one of the major
chloroplast components for photosynthesis, and relative chlorophyll content has an
important role in detecting the influence of water deficit conditions on plant (Guo et
al., 2008). Chlorophyll fluorescence parameters are considered as ideal method, gives
an insight into the health of the photosynthetic systems within the leaf in rapid and
sensitive way (Li et al., 2015; Li et al., 2013).
Lablab purpureus (L.) Sweet (synonyms: Dolichos purpureus, Dolichos lablab (NCBI
taxonomy)) in the Fabaceae family named locally as kashrangeeg in Nubia, Egypt.
The plant is used as a forage for grazing cattle, sheep, goats and pigs .Leaves and pods
are also used in popular medicine (Abd-elwahab et al., 2002). Lablab purpureus is a
drought-tolerant legume widely grown as a high-protein grain food in India and
similar climatic areas of Asia and Africa. The herbaceous plant is perennial and occurs
as bushy, semi-erect and prostate growth habit type (Guretzki et al., 2013).
Rhynchosia minima is a legume of indeterminate growth, annual or biennial, as
determined by environmental conditions. Our interest in studying this species is due to
its potential for use as a food and feed legume as it is readily consumed by herds in its
desert environment (Madueño et al., 2014), and it contained essential oils, tannins,
flavonoids, and triterpene steroids based on Jia et al. (2015). Therefore, how these
different environmentally legume related plants respond to drought stress. The
objective of this study is to evaluate the physiological responses of R. minima and L.
purpureus under heat and drought stresses and determine their potentialities as adapted
newly crops to extreme arid environmental condition prevailing in sub-tropical desert.
Materials and methods
Seeds of Hyacinth Bean (L. purpureus) procured from Aswan’s market and R. minima
collected from Wadi Agag in south eastern desert. Seeds were surface sterilized with
0.1% HgCl2 for 10 seconds and washed repeatedly with distilled water. Seed of R.
minima was scarified for 10 minutes
in a sulfuric acid solution (4N) to break
dormancy before sowing in a mix of sand and vermiculite (1:1 w/w), the plant were
cultured in pots and watered every 24 h in green house conditions, at 25°C, 16 h light
and 8 h dark photoperiod. Plants were grown for three weeks before transferring into
nursery at Research Unit for Studying plants of Arid Lands (RUSPAL) under stressed
climatic conditions in which the temperature reached 45°C. Two moisture levels were
utilized including 12% for control well-watered plants and 2% of the maximum
capacity for water retention which applied for stressed plants. Watering regime levels
were carried out by watering 12-week old plants as eighteen homogenous plants of
each species were selected (nine plants for each level of water regime). Full expanded
leaf samples were collected at time of measurement for enzymatic and metabolic
Measurement of transpiration and photosynthesis parameters 3
Measurements of the maximum quantum efficiency of PSII photochemistry,
photosynthesis rate, transpiration rate, leaf intercellular CO2 concentration and
chlorophyll fluorescence were performed by using infrared gas analyzer (IRGA, CI
340) photosynthesis system (CID Bio-Science, Inc.). Three individual plants were
selected from each measurement of well-watered control and stressed Plants.
Measurements were done on the 5th to 7th leaf. Measurement of light level was set to
PAR from 0 to 2500 µmol m−2 s−1, which was provided by a CI 301 LA light module.
Relative humidity in the leaf chamber was 50%, and the air temperature was
controlled at 40 ± 0.1 °C. The incoming air CO2 level in the leaf chamber was set at
360 ppm. The leaf was positioned in the leaf chamber and allowed to acclimatize to
the conditions in the chamber. The analyses were taken after stomata and
photosynthesis had stabilized, and the rates remained constant. Water use efficiency
(WUE) was determined using the following formula: WUE = the current net CO2
assimilation rate (Pn)/the current transpiration rate (E).
Chlorophyll fluorescence parameters, including initial fluorescence (Fo), maximum
fluorescence (Fm), variable fluorescence (Fv), and maximum quantum efficiency of
PSII (Fv/Fm) were monitored on the 4th leaf under both well-watered and drought
stress conditions using IRGA following the manufacturer’s instruction using CI- 510
CF chlorophyll fluorescence module.
2.2. Assays for PAL, SOD, CAT and POX activities
Frozen plant tissue (200 mg) was ground to a fine powder in a precooled mortar and
pestle, and 2 ml of extraction buffer [0.2 M phosphate buffer (pH 7.2), 0.1 mM EDTA,
1 mM DTT, and 2 U protease inhibitor cocktail] was added. The macerated suspension
was centrifuged at 10,000 rpm for 5 min at 4 °C. The supernatant was collected and
used as the source of enzyme. PAL activity was assayed by measuring the l-
phenylalanine formation at 290 nm using a UV-1800 UV–vis spectrophotometer
(Genesys 5, Thermo Spectronic, Rochester, NY, USA), and calculated using a
standard l-phenylalanine curve. The enzyme reaction mixture contained 100 mM
Tris−HCl, 40 mM trans-cinnamic acid, and an aliquot of the enzyme in a total volume
of 1 ml. PAL activity was expressed in U g−1 FW according to (Nagarathna et
al.,1993). SOD activity was determined by quantifying the inhibition in photo-
reduction of nitro blue tetra zolium (NBT) by SOD enzyme according to
(Giannopolitis et al., 1977). The reaction mixture contained 50 mM sodium carbonate,
50 mM sodium phosphate buffer (pH 7.6), 0.1 mM EDTA, 50 µM NBT, 10 µM
riboflavin, 12 mM L-methionine and 100 µl of crude extract in a final volume of 3.0
ml. The reaction mixture exposed to white light for 15 min at room temperature and
the absorbance was recorded at 560 nm using a spectrophotometer. A control reaction
was performed without crude extract. One unit (U) of SOD activity was defined as the
amount of enzyme causing 50% inhibition of photochemical reduction of NBT. POX
activity was estimated using a UV/Vis spectrophotometer (Genesys 5, Thermo
Spectronic, Rochester, NY, USA), as described previously (Kim and Yoo, 1996). The
reaction mixture, which consisted of 0.8 ml of 0.2 M phosphate buffer (pH 7.2), 1 ml
of 15 mM guaiacol, 1 ml of 3 mM hydrogen peroxide, and 0.2 ml of crude enzyme
extract, was incubated at room temperature for 3 min. The absorbance of the colored
product was monitored at 470 nm. POX activity expressed as∆470 g−1 fresh weight
(FW) min−1 was calculated using the following formula :U/ml = [Change in
absorbance min−1× Reaction mixture volume (ml) × Dilution factor]/ [ε470× Enzyme
extract volume (ml)]. CAT activity was determined spectrophotometrically at 240 nm
as described previously (Aebi, 1984). CAT activity expressed as ∆240 g−1FW min−1
was calculated using the following formula, modified with hydrogen peroxide
coefficient ε240: U/ml = [Change in absorbance min−1× Reaction mixture volume (ml)
× Dilution factor]/ [ε240× Enzyme extract volume (ml)].
2.3. Determination of total saponins
The dry materials were extracted according to the method described by Mostafa et al.
(2013). Total saponin content was determined spectrophotometricallyat 473 nm
(Ebrahimzadeh and Niknam, 1998). Saponin contents were calculated based on the
average value of absorbance at each concentration of the diosgenin standard.
2.4. Determination of total carbohydrates
The water-soluble carbohydrates and insoluble carbohydrates were quantified by an
anthrone-sulfuric acid method which carried out according to Fales (1951) and
(Trevelyan et al., 1952).The developed blue-green color was read at the wavelength of
2.5. Determination of total flavonoids
The total flavonoid content of the plant extract was determined by the aluminum
chloride colorimetric method using absorbance wavelength at 510 nm (Chang et al.,
2002). The total flavonoid content was calculated from a calibration curve, and the
result was expressed as mg quercetin equivalent per g dry weight.
2.6. Determination of total proteins
Total soluble and insoluble proteins were determined according to the method adopted
by (Lowry et al., 1951).
2.7. Determination of total phenolics
Total phenolics compounds were determined spectrophotometrically according to the
Folin-Ciocateu method (Ough et al., 1988).
2.8. Determination of ascorbic acid
Ascorbic acid content was assayed as described by (Omaye et al.,1979).
2.9. Determination of proline
Proline content of leaves was determined according to a modification of method of
(Bates et al., 1973).
2.10. Determination of chlorophyll content
We measure the chlorophyll content spectrophotometrically according to (Ni et al.,
2.11. Statistical analysis
Data obtained were subjected to a one-way analysis of variance (ANOVA). Significant
differences between the control and treatments (P ≤0.05) obtained by student t-test
using Minitab 12-21(Minitab Inc., 1998. Users' Guide 2: Data Analysis and Quality
Tools, Release 12:12, Minitab Inc.). Values shown in the figures are the means ±
standard errors (SEs) of three independent replicates.
3. Results 3.1.
Photosynthesis response against PAR
Photosynthesis (pn) of R. minima was higher than that of L. purpureus at 2500 mmol s-
m-2pn (6.29, 5.22) µmol s-1m-2 at 2 and 12% soil moisture content (Fig.1). As drought
stress increased pn of L. purpureus revealed that there were sharper decrement in
comparison to R. minima at high level of light intensity 1250 mmol s-1m-2 (0.82, 2.53
µmol s-1m-2), respectively. L. purpureus reached its maxima at 750 mmol s-1m-2 with
pn of 3.5 µmol s m . The pn of R. minima was significantly higher than those of L.
purpureus under drought stress and under high light intensity (>800 µmol m-2s-1)
Transpiration rate (E) of L. purpureus exhibited highest values with maximum of 5.32
mmol m-2s-1at PAR 2500 µmol m-2s-1. These values decreased sharply as soil water
content decrease reaching 1.0 mmol m-2s-1 at the same light intensity. R. minima
showed lower semi-constant values than those of L. purpureus at well-watered and
starved levels with 2.45 mmol m m-2s-1at PAR 2500 µmol m-2s-1 (Fig.1). E at 2% soil
water level showed stability ranged from 1.31 to 1.47 mmol m-2s-1at zero to 2500 µmol
m-2s-1PAR compared to L. purpureus at the same water regime. From two-way
analysis of variance, L. purpureus photosynthesis showed differences attributed to
PAR and soil moisture content (SMC) where F= 63.95, P<0.0001 and F= 5.04,
P<0.001 respectively, while transpiration rate indicated differences attributed to SMC
where F= 20.70, P<0.0001. In R. minima the photosynthesis showed differences
attributed to SMC where F= 16.40, P<0.001, while transpiration rate indicated
differences attributed to SMC and PAR where F= 16.9, P<0.0001 and F= 6.06,
Transpiration (E) and photosynthesis (pn) of L. purpureus and R. minima are strongly
linked. The relationship between Pn and E can be studied in greater details by
examining the ratio Pn/E, an index of short-term water-use efficiency (WUE). Under
well-watered conditions, are generally functions of net radiation, in R .minima at 12%
water regime a maximum WUE (2.45µmolm S /mol m s ) reached at highly PAR
2500 µmol m-2s-1while at 2% a maximum value of WUE (1.93µmolm-2S-1/mol m-2s-1)
at PAR 1250 µmol m-2s-1. In L. purpureus at 12% WUE showed a high value
(1.10µmolm-2S-1/mol m-2s-1 at PAR 2500 while WUE at 2% showing maximum value
(3.63 µmolm-2S-1/mol m-2s-1 at 750µmol m-2s-1. (Fig.1)
3.4. Changes in R. minima and L. purpureus metabolite contents and antioxidant
activities in response to drought stress
R. minima showed a higher stress tolerance than L. purpureus with highly activity of
antioxidant enzymes (superoxide dismutase, catalase, peroxidase and phenyl ammonia
lyase) to avoid the oxidative damage of reactive oxygen species (Fig.2). The obtained
results showed that SOD, CAT, POD and PAL were signficantly higher (58.7, 64.91,
49.34, 84.26 U g FW, respectively) in stressed R. minima, compared with their well-
watered controls (16.99, 13.68, 28.54, and 29.22 U g-1 FW, respectively), In stressed
L. purpureus, these enzymes showed slight increase (17.39, 22.77, 31.49, 45.00 U g-1
FW, respectively) compared to their unstressed well-watered plants (13, 16.53, 17.44
and 27.7 U g-1 FW, respectively). Generally, the results of SOD, CAT, POD and PAL
activities were higher in R. minima than L. purpureus under drought stress condition.
Stressed plants showed a different change in metabolite content in which stressed L.
purpureus had a higher content of ascorbic acid, saponins, insoluble proteins, soluble
carbohydrates (131.4, 107.33 and 150 and 106.99 mg g-1 DW, respectively) in
corresponding to unstressed plants. Under drought stress, L. purpureus showed
decrease in insoluble carbohydrates, proline and phenolics (100.3,4.0 and 4.5 mg g-1
Stressed R. minima revealed significant increase in soluble,
insoluble proteins and flavonoids (74.9, 219.5 and 70.8 mg g-1 DW, respectively)
while insoluble carbohydrates, ascorbic acid and phenolics content decreased with
drought stress severity (42.7, 22, 4.5 and 5.8 mg g-1 DW, respectively). R. minima
showed no significant change (P≥ 0.05) in ascorbic acid, saponins and proline (Fig3).
3.5. Chlorophyll and chlorophyll fluorescence
In stressed plants chl a was similar in L. purpureus and R. minima of about 1.01 mg /g
FW. Chl b in R. minima showed values of 1.40 mg /g F.W while in L. purpureus chl b
was 0.5mg /g FW. Under well-watered conditions, the correlations among initial
fluorescence (Fo), maximal fluorescence (Fm), variable fluorescence (Fv) and Fv/Fm
were highly significant (P<0.01), The Fv/Fm was decreased with the decrease in soil
water potential (Fig.4), but Fv/Fm of L. purpureus decreased sharply than those
corresponding to R. minima. A significantly positive correlation between Fv/Fm ratio
and SMC (r=0.743 and p= 0.006) was found, In chlorophyll a content there was no
significant differences (P > 0.05) but there was a significant difference in chlorophyll
b (p < 0.05) between these two plant species (Fig. 5).
Water deficit is an important limiting factor that affects all physiological processes
including growth and developments of plants (Centritto et al., 2009). It can inhibit
activity of enzymes related to Calvin cycle and inhibits activity of PSII, which is the
primary cause of the photosynthetic rate decrease (Taiz et al., 2017). Our results
showed that especially Pn decreased dramatically under drought stress and increased
under high photosynthetically active radiation (PAR) in L. purpureus, while in R.
minima the photosynthesis rate remained the same during reducing the water
availability under high PAR. High leaf WUE is a water-saving strategy allowing plants
to maintain strong drought tolerance. It is generally believed that reduced transpiration
and increased photosynthesis jointly lead to improvement in leaf WUE (Base et al.
2016). In our study, R. minima showed increasing in WUE at high PAR where in L.
purpureus the WUE showed lower value at the same PAR under severe drought stress.
These results showed agreement with Santos et al. (2017) study on Ricinus communis.
R. minima was more tolerant to drought stress than L. purpureus explaining how desert
plants have the ability to increase their photosynthetic rate in response to increasing
PAR under high water regime and decreasing transpiration rate to guarantee a higher
WUE. By different mechanisms such as closing stomata and condense root system,
these plants can prevent water content loss, and thereby reduce levels of tissue damage
(Li. Y et al., 2017).
Another strategy is a system including important protective antioxidant enzymes in
which SOD, PAL, POD and CAT played an important role in scavenging harmful
oxygen species (Li-Pet al., 2006). The amount of antioxidant enzymes activity in L.
purpureus were lower in compared to R. minima which may reflect the low ROS
scavenging capacity and increased damage in L. purpureus.
The comparison between the four enzymes indicated that activity of PAL was highest
and CAT, SOD and POX came next. This result indicates that PAL was the main
protective enzyme against the drought stress. Some previous studies reported that
SOD was more sensitive to the drought stress than other enzymes (Li et al., 2015), also
(Iturbe-o et al., 1998) demonstrated that pea plants that exposed to mild drought stress
showed increase in SOD activity and severe decrease in CAT activity .
Plants produce new metabolites and can also alter composition of existing chemicals
to survive in different environmental stresses (Qasim et al., 2017) such as
carbohydrates which is considered sensitive osmotic markers for drought stress and
presence of flavonoids, phenolics and saponins in plant responsible for antimicrobial
activity and antioxidant effect. Results from this study showed that L. purpureus is a
good source for proteins and carbohydrates while R. minima was rich in flavonoid and
phenolic compounds. Ascorbic acid is an antioxidant compound accumulated in plant
reducing the damage caused by ROS (Reddy et al., 2004). Our experiment revealed
that L. purpureus and R. minima contained considerable amount of proline has been
reported to act as an osmo-protectant, a protein stabilizer, a metal chelator and an
inhibitor of lipid peroxidation (Kokila et al., 2014). Chlorophyll fluorescence emitted
from plant leaves enables to monitor and quantify the changes induced in the
photosynthetic apparatus rapidly during drought stress. Decreases in Fv/Fm was
dependent on stress severity (Yang et al., 2014).Fv/Fm decreased dramatically with
soil water potentials declining in both R. minima and L. purpureus. The R. minima
maintained the higher Fv/Fm than L. purpureus. A study on sugar beet showed
decreasing in Fo values and increasing in Fv/Fm during the later stage of drought
stress. Our result also showed decrease in Fo which could reflect damage to PSII and it
is in agreement with (Guo et al., 2008) and (Li et al., 2015) finding in their research.
Rhynchosia minima is an ideal desert plant acts as water saver under extreme arid
environment and maybe promising potential feed and food crop.
Drought stress affects plant development processes, reduces transpiration and
photosynthetic rates, and leads to poor productivity. The two legume plants Lablab
purpureus and Rhynchosia minima have differential responses and various signaling
pathways to minimize the deleterious effects of water stress. This study showed that R.
minima maintained higher photosynthetic and transpiration rate than that of L.
purpureus under low water regime (2%). R. minima performed better than L.
purpureus under severe drought stress and that was attributed to its strong antioxidant
enzymes system and the higher accumulation of compatible solutes and proteins.
Conflict of interest: The authors declare that they have no conflict of interest.
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Fig.1. photosynthesis rate (Pn), Transpiration rate (E) and water use efficiency (WUE) for L. purpureus and R. minima under different soil moisture contents (12 and 2 % by weight) and at different photosynthetic active radiation (PAR).
Fig. 2. Differences in antioxidant enzyme activity between well watered (12%) L. purpureus, stressed (2%) L. purpureus, well watered (12%) R. minima and stressed (2%) R. minima. Catalase, CAT; Peroxidase, POX; Superoxide dismutase, SOD and Phenylalanine ammonia lyase, PAL. Values are means ± standard errors (SEs) of three independent replicates (n =3). Asterisks indicate significant difference as determined by a Student’s ttest (*P < 0.05; **P < 0.01;***P < 0.001).
Fig. 3. Differences in soluble and insoluble carbohydrate contents, soluble and insoluble protein contents, phenolics, saponins, flavonoids, ascorbic acid and proline (mg g−1 DW) between well watered (12%) L. purpureus, stressed (2%) L. purpureus, well watered (12%) R. minima and stressed (2%) R. minima. Values are means ± standard errors (SEs) of three independent replicates (n = 3). Asterisks indicate significant difference in L. purpureus and R. minima, as determined by a Student’s t-test (*P < 0.05; **P < 0.01; ***P < 0.001).
Fig.4. The effects of the drought stress on the maximum photochemical quantum yield of PS II (Fv/Fm) in compared to well-watered plant.
Fig.5. Chlorophyll content of well watered (12%) L. purpureus leaves, stressed (2%) L. purpureus, well watered (12%) R. minima and stressed (2%) R. minima under two level of water regime 12% and 2%. Values are means ± standard errors (SEs) of three independent replicates (n = 3). Asterisks indicate significant difference in L. purpureus and R. minima, as determined by a Student’s t-test (*P < 0.05; **P < 0.01; ***P < 0.001).
Highlights • • • • •
Changes in physiological behavior between desert and riverain legume plants was compared. The rate of transpiration in desert plant Rhynchosia minima was lower than Lablab purpureus under high water regime. The photosynthesis rate decreased by increasing drought stress in all plants. Drought stress induced significant accumulation of total sugars, flavonoids, saponins ,protiens and phenolics. Rhynchosia minima is an ideal desert plant acting as water saver under extreme arid environment.