Maryam Kaamali; Mahmoud Shour; Seyyed Hossein Neamati; A Lakziyan; Hamidreza Khazaie
Abstract
Introduction: Water deficiency is one of important abiotic stresses that severely effects on plant growth. The effects of drought range from morphological to molecular levels and are evident at all phenological stages of plant growth at whatever stage the water deficit takes place. Growth is accomplished ...
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Introduction: Water deficiency is one of important abiotic stresses that severely effects on plant growth. The effects of drought range from morphological to molecular levels and are evident at all phenological stages of plant growth at whatever stage the water deficit takes place. Growth is accomplished through cell division, cell enlargement and differentiation, and involves genetic, physiological, ecological and morphological events and their complex interactions. The quality and quantity of plant growth depend on these events, which are affected by water deficit. Cell growth is one of the most drought-sensitive physiological processes due to the reduction in turgor pressure. Under severe water deficiency, cell elongation of higher plants can be inhibited by interruption of water flow from the xylem to the surrounding elongating cells. Impaired mitosis, cell elongation and expansion result in reduced plant height, leaf area and crop growth under drought. Chlorophyll content is one of the major factors affecting photosynthetic capacity changing in chlorophyll content of plant under drought stress has been observed in different plant species and its intensity depends on stress rate and duration. Chlorophyll content of leaf is indicator of photosynthetic capability of plant tissues. In the mid-80s, RWC was introduced as a best criterion for plant water status which, afterwards was used instead of plant water potential as RWC referring to its relation with cell volume, accurately can indicate the balance between absorbed water by plant and consumed through transpiration.
Materials and Methods: To study the effects of drought stress on three varieties of petunia, a factorial experiment based on randomized complete block design with four replications was conducted. The treatments consisted of four irrigation levels ((100% control), 80%, 60% and 40% of field capacity) and three varieties of petunia (Supercascade, Tango blue and Tango white). After planting and transplanting and after full deployment in the pot, water stress treatments were applied on three varieties of petunias. At the end of each week fully blossomed flowers were counted, flower diameter, peduncle length and corolla length were measured. In order to determine the stability of the cell membrane electrolyte leakage index was measured. Specific leaf area (SLA) was determined. The amount of chlorophyll a, b, total and carotenoid and relative water content in the leaves were measured. Statistical analysis was performed using the software MSTAT-C. EXCEL was used for diagramming software. Means were compared using LSD test with a 0.05 significance level.
Results and Discussion: Results indicated that interaction impacts of variety and irrigation on dry weight, leaf area, flower number, flower diameter, length Corolla, chlorophyll content, electrolyte leakage, relative water content and proline content was significant. The most shoot dry weight (76/1 g) was in control stress (100% FC) and Tango White variety. Also the most leaf dry weight (07/2 g) and root dry weight (g 43/0) were in Tango Blue variety. With increasing drought stress from 100% FC to 40% FC, leaf area decreased in Supercascade from 314 to 49, in Tango Blue from 405 to 44 and in Tango White from 459 to 69 cm2. In 80% FC, electrolyte leakage increased in all varieties (Supercascade variety 2%, Tango Blue 10% and in Tango White 3%) compared to control. Also electrolyte leakage increased in Supercascade 17%, in Tango Blue 9% and in Tango White10% in 40% FC compared to control. Comparison of interaction effects of drought stress and variety also showed the most proline had accumulated in Tango White and drought 40% of field capacity and then in Tango Blue and stress 40% of field capacity. Generally two varieties of Tango Blue and Tango White in control irrigation had better growth and also in low irrigation were more resistant.
Maryam Kamali; Mahmoud Shour; Hassan Feizi
Abstract
Introduction: Titanium is the ninth most abundant element and the second most transition metal found in the earth’s crust (about 6.320 ppm). There has been a rising demand for nanotechnology-based products in recent years, particularly in areas directly related to humans. Nanotechnology has many applications ...
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Introduction: Titanium is the ninth most abundant element and the second most transition metal found in the earth’s crust (about 6.320 ppm). There has been a rising demand for nanotechnology-based products in recent years, particularly in areas directly related to humans. Nanotechnology has many applications in agricultural research, such as in reproductive science and technology, the transfer of agricultural and food waste to energy and other helpful by-products through enzymatic nanobioprocessing.
An important effect of titanium compounds on plants used for improvement of yield (about 10–20%) in various crops. Other effects of titanium on plants are increasing contents of some essential elements in plant tissue; an increase in enzyme activity such as peroxidase, catalase, and nitrate reductase activities in plant tissue, and research has shown increased chlorophyll content in paprika (Capsicum anuum L.) and green alga (Chlorella pyrenoidosa). Nanotechnologyapplication is now widely distributed throughout life, and especially in agricultural systems. Nano particles, because of their physicochemical characteristics, have been considered the potential candidates for modulating the redox status and changing in seed germination, growth, performance, and quality of plants.nano-TiO2 has shown to be potential for agricultural application because of its photocatalytic disinfection and photobiological effects. Also,stalinizationof soils or waters is one of the world’s most serious environmental problemsin agriculture. During initial exposure to salinity, plants experience water stress, which in return reduces leaf expansion. during long-term exposure to salinity, plants experience to ionic stress, which can lead to premature senescence of adult leaves, which led to a reduction in the photosynthetic area available to support plants growth.However,a few studies have been done on the effects of nanoparticles on ornamental plants. Nanosized TiO2 is a frequently used nanoparticle, consequently there has been an exponential increase in data collection on the effects of TiO2 nanoparticles on different species. There is much less information on the effects of nanoparticles on plants compared to animals. Studies of the effects of TiO2 nanoparticles on plants provide information about the positive and stimulating effects as well as any negative impact. In this study, weaimedto findout the phytotoxicity or positive effects of different concentrations of Bulk TiO2 and nanosized TiO2 on plant growth of Petunia hybridain salinity stress.
Material and Method: experiments were done to assess the effect of different concentrationsof bulk and nanosized TiO2 on petunia growthin salinity stress in a factorial test based on completely randomized design with 3 replications in agriculture faculty of Ferdowsi University, Mashhad. There were 3 factors, including1- three concentrations (0, 75 and 150 mM) of NaCl, 2- bulk and Nanosized titanium dioxide and 3- six concentrations (0, 5, 10, 15, 20 and 40 ppm) of TiO2. Titanium dioxide treatments for foliar application was applied 5 times with intervals of seven days (three times before, and twice after starting salinity stress). The experiment was performed at the College of Agriculture, Ferdowsi University of Mashhad. during the flowering, flower number, corolla length, flower diameter and flower fresh weight were measured. At the end of the flowering phase, parameters such as leaf area, shoot and leaf fresh weight, lateral shoot number, leaf number, chlorophyll a, b, total and cartenoidwere measured. The data were subjected to Analysis of Variance, was done using Mstat-C statistical. The means were separated, using LSD test.
Results and Discussion: Results showed that interaction of salinity, bulk and nanosized titanium dioxide and titanium dioxide concentrationsweresignificanton total chlorophyll, cartenoides, biomass, leaf area and flower number. The highest amount of total chlorophyll concentrations was measured in 20 and 40 ppm TiO2 and 5 ppm Nano treatments, respectively. The highest leaf area (608 cm2) was in 15 ppm Nano treatment. Among levels of nano TiO2,foliar application with 5 ppm had the best flower diameter in general, foliar application of nano titanium dioxide and titanium dioxide have been effective in improving the effects of salinity stress. In addition, the use of titanium dioxide in the highest level (40 ppm) and use of nano titanium dioxide in less concentration in Petunia plant had better effect on morphological traits. An important effect of titanium compounds on plants used for various crops is yield improvement. The positive effects of TiO2 could be probably due to the antimicrobial properties of engineered nanoparticles, which can enhance strength andresistance of plants to stress.
