Water Stress In Plants Causes Effects And Responses Pdf
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- Water Stress in Plants: Causes, Effects and Responses
- Response of plants to water stress
Water Stress in Plants: Causes, Effects and Responses
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. 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.
In semiarid and arid regions particularly during spring and summer months, the evaporative demand for the atmosphere results in significant drought stress in many crop plants, which is one of the most severe environmental stresses and affects almost all plant functions. In these conditions, water stress causes serious reduction in growth, quantity, and quality in many plants [ 1 , 2 ].
It frequently occurs in both intensive fruit orchards and nurseries in many parts of the world. This situation directed researchers to make further investigations to reduce severe effects of water stress on different plant species.
Therefore, new approaches including effective use of water, selection of drought resistant species, cultivars, and rootstocks have been considered to reduce the effects of water stress. Severity of water stress has a great impact on the physiological and biochemical process of plants [ 3 , 4 ].
Plant responses to water stress are usually screened on the level of selected physiological parameters such as water potential, relative water content, stomatal reactions, photosynthesis, or osmotic adjustment which have been proven to be good indicators of drought in several studies [ 3 , 5 , 6 ].
In addition, studies of carbohydrate accumulation and characterization of fruit trees to drought stress have also been involved [ 7 ] as well as plant hormones such as ethylene production [ 8 , 9 ].
In recent studies, active oxygen species AOS and antioxidative enzymatic responses have also been proposed [ 10 — 13 ]. A nursery plant is composed of two parts; stock and scion. The rootstock has potential to affect the characteristics of scion precocity, growth, productivity, fruit quality, and resistance to biotic and abiotic stress [ 14 ].
The rootstock which has ability to tolerate partial or fully drought condition is the best material for budding because it has been stated that, in grafted plants, amount of water transporting from roots to shoots is controlled by rootstock [ 15 , 16 ] and also drought tolerance of rootstock is conferred to grafted scions [ 15 ]. Tolerance levels of rootstocks which belong to different fruit species against environmental stress have been intensively studied recently [ 13 , 17 , 18 ].
The possible drought and irrigation problems would definitely affect the rootstock growth and the budding success, and, therefore, it would result in reduction in nursery and crop productivity as well as economic loss. However, there is limited information on grafting and budding success rate in rootstocks under water stress conditions. More recently, the international well-known standard M9 and MA rootstocks have been used in intensive fruit orchards for apples and pears particularly in semiarid and arid conditions where water stress is the main issue.
Therefore, the aim of the study was to identify budding efficiency and some physiological and biochemical responses of the rootstocks based on the parameters evaluated in dwarf apple and quince rootstocks. July and August are the warmest months with almost no rainfall. In this research, dwarf M9 apple and MA quince rootstocks were used and Vista Bella apple and Santa Maria pear cultivars were used as scions, respectively.
The exposed top of growth medium within the pot was covered with an opaque plastic film during the experimental period and tied around the base of the stem to prevent vapor phase water movement within the growth medium and to minimize water loss from the pot surface. All plants were then placed on a bench in outside conditions. A polyethylene PE cover was also employed in case of rain during the experimental period.
Potted rootstock plants were equally irrigated until the start of the experiment April till mid-July. The amount of water applied to each pot was determined by preliminary studies based on the pot capacity PC. Control plants were maintained at full PC throughout the experiment. Each treatment was set up in a randomized block design with three replicates, each consisting of 10 plants. Water stress irrigation treatments were imposed from mid-July until the beginning of dormant period.
Meanwhile, in the beginning of September, 5 plants from each replicate out of each treatment were randomly selected for some morphological, physiological, and biochemical evaluation.
The rest of the plants in each replicate were used for chip budding and preserved until the following season. During the dormant period no irrigation was made. In the following season, spring, the budded plants were water-stressed as in the previous year until the budding success evaluation was completed.
Fertilization of rootstocks was routinely applied with half-strength of Hoagland solution once a week during the experimental period. Terminal shoot lengths and diameters were measured both at the beginning of water stress irrigation treatment mid-July and in the beginning of September in which 7-week water stress was achieved.
At the end of this period, whole plants of M9 and MA rootstocks were uprooted and cleaned with tap water and fresh and dry weights were determined. RWC was determined form the upper fully expanded young leaves at noon pm according to Yamasaki and Dillenburg [ 19 ]. Leaf relative water content was calculated according to the equation:.
CI was evaluated in the upper fully expanded young leaves with a Field Scout CM chlorophyll meter. Measurements were made on a clear day between 12 and 14 pm.
EL was assessed as described by Lutts et al. Fully expanded young leaf samples were washed three times with deionized water to remove surface-adhered electrolytes. The electrolyte leakage was calculated as follows:. Young fully expanded leaf samples from the rootstocks were collected for biochemical measurements. The supernatant filtered through two layers of cheese-cloth was used for the determination of enzymatic activities as well as protein determination.
The reaction mixture consisted of 0. The biochemical reaction was started by adding 0. Samples without H 2 O 2 were used as blank. A change of 0. Anthocyanin contents of leaves were determined according to the method of [ 23 ]. Phenol content of leaves was determined according to Singleton and Rossi [ 24 ] by using Folin-Ciocalteu solution with slight modifications.
Fresh leaf tissues of 0. Then 1. The standard solution of gallic acid was reacted as stated above. Proline content of the leaves was measured according to Bates et al. Proline was extracted from 0.
The standard curve was prepared by employing L-proline. At the beginning of September after 7-week water stress treatments , chip budding was made on the rest of the rootstocks. After inserting the buds, they are taped with white rubber.
The ties were removed off five weeks following budding to avoid damages resulting from the trunk expansion in the stock. Budding success was evaluated on the first week of coming April at which time shoot growth on successful buds was about 2.
Transformation and statistical analysis were made through these values. In this study, water stresses were evaluated on shoot growth parameters in two rootstocks. At the same conditions, decline in RSD was Significant differences were recorded for all watering regimes. Plant growth was also reduced under the negative effects of water stress in apple [ 27 ] and pear [ 17 ] depending on the rootstocks.
The apple and quince rootstocks responded similarly to water stress on accumulation of fresh and dry weight Table 1. Water stress inhibited fresh and dry weight accumulation in both rootstocks. Therefore, drought-induced decreases of rootstocks in terms of fresh and dry weights were accompanied with the increase of water stress. Similarly, Thomas Fernandez et al. Sakalauskaite et al. In two rootstocks, RWC decreased with the increasing levels of water stress.
Similarly, it is reported that in pear [ 17 ] and in Malus prunifolia and Malus hupehensis [ 13 ], the negative effects of water stress on leaf RWC were reduced depending on the rootstock genotypes. Leaf RWC reflecting the metabolic activity in tissues [ 29 ] declined significantly due to water stress Table 1. Such a decrease in leaf RWC could have been due to unavailability of water in the soil [ 30 ], or root systems, which are not able to compensate for water, lost by transpiration through a reduction of absorbing surface [ 31 ].
Water stress regimes also resulted in decrease in CI levels in both rootstocks during the period of stress Table 2. Similar findings were also reported by Alizadeh et al. Humidity contents were reduced in both pots of rootstocks and, as a result of that, EL content increased. For example, EL level increased from Similarly, increase of EL was determined by Gholami et al.
EL increase is accompanied with the increase of cell permeability; thus, an important strategy for the development of drought resistance should involve the maintenance of cell membrane integrity.
For example, Wang et al. Irrigation withheld for 12 d led to considerable ultrastructural alterations in organelles in which M. Water stress negatively affected the success of budding in both rootstocks. Increase in the water stress resulted in decreasing of budding success. The budding success was Similar situation was reported by Sauve et al. Since above treatments reflected the condition of semiarid and arid regions, budding efficiency is, therefore, significantly affected.
However, this rate significantly dropped with the increase of water stress. It is thought that water uptake and translocation during the budding are more efficient within the genus than between different genera. There were also strong correlations between vegetative parameters, biomass production, CI, EL, and budding success for each rootstock Table 3.
In addition, morphological, physiological, and biochemical parameters of apple and quince rootstocks to water stress were quite variable. This variability could be associated with the rootstock, water stress level, intensity of stress, and environmental conditions. When biochemical parameters were evaluated, catalase level did not show significant difference from the control group although peroxidase activity in both rootstocks was higher compared with plants under control conditions Figures 2 a and 2 b.
Water stress adversely impacts many aspects of the physiology of plants, especially photosynthetic capacity. If the stress is prolonged, plant growth, and productivity are severely diminished. Plants have evolved complex physiological and biochemical adaptations to adjust and adapt to a variety of environmental stresses. The molecular and physiological mechanisms associated with water-stress tolerance and water-use efficiency have been extensively studied. The systems that regulate plant adaptation to water stress through a sophisticated regulatory network are the subject of the current review.
Ahmad, N. Drought stress in maize causes differential acclimation responses of glutathione and sulfur metabolism in leaves and roots. BMC Plant Biology, 16, Albert, R. A new discrete dynamic model of ABA-induced stomatal closure predicts key feedback loops.
Key plant products and common mechanisms utilized by plants in water deficit stress responses. Plants are always exposed to fluctuation of environmental factors. Water stress is one of the main abiotic factors limiting plant growth and development on most areas of the world. Declining available water triggers various adaptive processes to cope with water deficit stress. These mechanisms can be categorized into escape, avoidance and tolerance strategies. Avoidance mechanisms are employed to maintain the balance between water uptake and water loss, while tolerance mechanisms are trying to keep the plant functions the same level as unstressed level. Major molecular mechanisms attributed as tolerance strategies include osmotic adjustment, Reactive Oxygen Species ROS scavenging, cellular components protection membrane lipid changes and hormone inductions.
Response of plants to water stress
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.
The soybean [ Glycine max L. Low water availability in the growing environment can cause soybean plants to suffer from drought stress. Giving hydrogen peroxide to plants experiencing drought stress in optimum concentration can increase the plant's oxidative defense system. This study aims to determine the effect of treatment on the vegetative growth of Argomulyo variety soybean plants. The study used a factorial completely randomized design CRD design with 2x4 treatment and 5 replications.