Pomology
Tavakil Rasteh; Javad Erfani moghadam; Seyyed Samih Marashi
Abstract
IntroductionThe date palm (Phoenix dactylifera L.) belongs to the family Arecaceae is a dioecious trees. Due to the problems of non-overlapping flowering of some male and female palm trees, commercial date production requires artificial pollination. Temperature is an important environmental factor influencing ...
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IntroductionThe date palm (Phoenix dactylifera L.) belongs to the family Arecaceae is a dioecious trees. Due to the problems of non-overlapping flowering of some male and female palm trees, commercial date production requires artificial pollination. Temperature is an important environmental factor influencing the pollination, fertilization and fruit set of the date palm. Availability of efficient male pollinators are of great importance in date palm production chain and for regular yearly bearing as the quantity and quality of pollen is a yield determining factor. The flowering and pollination period of date palm varies upon cultivar, geographic location and climatic conditions. However, frequent asynchronous flowering of date palm male and female trees occur due to climatic changes and abiotic stress. In such cases, farmers may pollinate their trees with pollen of a known male conserved at ambient conditions from the previous season; however, this is mostly result in a low fruit set and yield.Materials and MethodsIn this study, a factorial test was performed based on a completely random design with three replications at the laboratory of the Horticulture department at Ilam University to determine the rate of germination in five male date palm cultivars. The first factor consisted of nine temperature levels of 15, 18, 21, 24, 27, 30, 33, 36 and 39 and the second factor referred to the cultivar of the pollinator which had five levels of ‘Ghanami Sorkh’, ‘Ghanami Sabz’, ‘Sabz Parak’, ‘Nare Pakutah’ and ‘Khareji’. The pollen of the above-mentioned cultivars was obtained from the date palm Germplasm collection at the Date Palm and Iranian Tropical Fruits Institute in the city of Ahwaz. In the early days of the flowering season (March), the cultivars under study were identified and labeled. They were then checked on a daily basis and whenever the sheaths were ripe enough, they were picked and preserved in a sterile environment in room temperature. After the sheaths opened, the flower clusters were dried in the same environment and at the same temperature. Then, the cluster strings were separated and kept in a freezer at -18 °C until it was time for the test. Viability and vitality of the pollen was specified through the dying method using Acetocarmine solution.Results and DiscussionThe results showed that there was a significant difference among cultivars, temperature and interactions of them at the level of 1%. Among the studied temperatures, the highest germination of pollen grains in all cultivars occurred at 30 °C, followed by 33 °C and 27 °C, respectively, and the lowest germination percentage were obtained at 15 °C. Among cultivars, the percentage of pollen germination in ‘Ghanami Sorkh’ was quite high (92.45%), and ‘Nare Pakutah’ (87.33%), also, simultaneously ‘Sabz Parak’ (84.82%) and in the ‘Khareji’ cultivar was the lowest. However, the percentage of pollen germination in ‘Ghanami Sorkh’ cultivar was higher than 59% under a wide range of temperature from 21 to 39 °C. Furthermore, the percentage of Pollen germination was reduced rapidly at temperatures less than 21 Cº and reach 15.85% in 15 °C. The germination percentage of pollen grains in ‘Nare Pakutah’ cultivar in the temperature range of 21 to 39 degrees Celsius was higher than 57%. The germination percentage of pollen grains in ‘Sabz Parak’ cultivar decreased with less acceleration than ‘Ghanami Sorkh’ at lower and upper temperatures of 30 °C, so that at 36 and 39 °C had the highest amount of germination compared to the other cultivars. Also, the germination rate of pollens in ‘Ghanami Sorkh’ cultivar were investigated above 57% in the wide temperature range from 21 to 39 °C.ConclusionAccording to the findings of this study, the timing of pollination plays a crucial role in the fertility of male date palm cultivars, with the optimal temperature being around 30°C. It is essential to select cultivars that exhibit a high rate of pollen germination and contribute positively to fruit properties. Male cultivars such as 'Ghanami Sorkh', 'Sabz Parak', and 'Nare Pakutah' demonstrated a broader range of optimum temperatures for pollen germination. Therefore, these cultivars are recommended for climates characterized by significant temperature fluctuations during the flowering period of female date palms.
Growing vegetables
Zahra Darabi; Fardin Ghanbari; Javad Erfani moghadam
Abstract
Introduction
Low temperature is one of the most important environmental stresses that cause damage to plants and limit the geographical distribution of plant species. Plants of tropical and sub-tropical origin, such as cucumbers, are sensitive to cold stress and severely damaged at low temperatures. ...
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Introduction
Low temperature is one of the most important environmental stresses that cause damage to plants and limit the geographical distribution of plant species. Plants of tropical and sub-tropical origin, such as cucumbers, are sensitive to cold stress and severely damaged at low temperatures. Plants have evolved a set of defense mechanisms to adapt to low temperatures. These mechanisms include the regulation of gene expression and physiological and biochemical changes that increase plant resistance to chilling stress. Cinnamic acid (CA) is one of the most important phenolic acids present in all plants and has antimicrobial properties against fungi and bacteria. The application of this compound in some plants causes oxidative stress and leads to the activation of antioxidant enzymes. Therefore, in the present study, the effects of exogenous cinnamic acid treatment on cold stress tolerance in cucumber seedlings have been investigated.
Materials and Methods
This research was conducted in the greenhouse and laboratory of the Department of Horticultural Sciences of Ilam University in 2019. Cucumber seeds (Super Daminus cultivar) were planted in a 1: 1: 1 ratio of field soil, manure, and sand. In the fully developed two-leaf stage, seedlings produced were sprayed using cinnamic acid (at concentrations of 0, 50, 100, and 200 μM). Foliar spraying treatments were applied at the mentioned concentrations until the surface of the leaves was completely wet. 24 hours after foliar application, all plants were exposed to cold stress at 3 ° C for 6 hours in six consecutive days. After applying the cold treatment, the seedlings were transferred to the greenhouse and 72 hours later, the traits were measured.
Results and Discussion
The results showed that exogenous CA application increased the growth characteristics of cucumber seedlings subjected to chilling stress. Improving the growth and development of plants under stress conditions by cinnamic acid treatment has been reported in other studies, which is consistent with the results of the present study. It has been reported that cinnamic acid treatment, by causing oxidative shock in plants, leads to plant defensive responses to stress conditions, and through this, plants can better withstand stress conditions. These defense responses include increasing compatible solutions and improving the antioxidant system. In the present study, the use of cinnamic acid treatment increased proline, chlorophyll, and total phenol and reduced of membrane lipid peroxidation, and these changes led to a decrease in the apparent effects of cold on cucumber seedlings.
The use of chemicals that can mitigate the effects of cold on the plant can also help maintain plant growth under cold stress. In the present study, the application of cinnamic acid improved the growth of cucumber seedlings under cold stress conditions. Cinnamic acid pretreatment by inducing antioxidant compounds reduced the effects of cold on cucumber seedlings and improved plant growth in chilling conditions. Also, cinnamic acid treatment increased the growth of pepper plants under salinity stress, cucumber under drought stress, and wheat under drought conditions, which is consistent with the results of the present study. Therefore, it can be said that cinnamic acid improves plant growth under stress by changing physiological and biochemical processes. The results showed that the application of cinnamic acid improved the growth of cucumber seedlings under chilling stress conditions. Cinnamic acid pretreatment caused a significant increase in relative water content (25 to 32%), chlorophyll (108 to 125%), proline (152 to 244%), and total phenol (31%) compared to the control, therefore improving the adaptabilities of cucumber seedlings to chilling stress. The application of cinnamic acid also reduced the damage to cell membranes. The electrolyte leakage and malondialdehyde accumulation of cinnamic acid-treated seedlings were lower than that of control seedlings.
Conclusion
In general, the results of this study showed that the application of cinnamic acid reduced the effects of cold stress on cucumber seedlings. These results were associated with increased proline, chlorophyll, phenol and relative water content, in this way, the rate of ion leakage and accumulation of malondialdehyde in cucumber seedlings were reduced under cold stress. In general, the results showed that cinnamic acid treatment (especially concentration of 200 μM) can effectively reduce the effects of chilling on cucumber seedlings and improve their growth under cold stress.
