جستجوی مقالات مرتبط با کلیدواژه "source" در نشریات گروه "زراعت"

Silicon is increasingly recognized as a beneficial element for improving plant growth by enhancing physiological, biochemical, and molecular responses. It plays a role in various plant processes like osmosis, metabolism, stomatal physiology, and phytohormone relationships. Some researchers believe that silicon, as a signaling molecule, reduces damage caused by reactive oxygen species and ionic leakage by increasing the plant's antioxidant defense capacity. silicon plays a significant role in increasing the accumulation of photosynthetic materials in seeds; researchers attribute this increase to the flow of assimilates towards the seed, reduced source limitation, enhanced sink capacity, and improved remobilization of photosynthetic materials. The results indicate that silicon can affect the production and allocation of dry matter and the relationship between source strength and sink size. The consumption of silicon leads to favorable interactions with fertilizer elements such as potassium, thereby enhancing agronomic traits and improving the efficiency of this element to increase yield. Potassium plays a crucial role in osmotic control, enzyme activity, regulating cell pH, maintaining the balance between anions and cations within cells, controlling evaporation and transpiration through stomatal regulation, and aiding in the transport of metabolic materials from photosynthetic activities, ultimately improving yield by increasing leaf area and chlorophyll content. It has been shown that the application of silicon improves biomass, seed yield, and tiller number in several crops. Bitter vetch is a forage plant from the legume family and is native to regions in West and Southwest Asia, cultivated in various countries, including Iran. Bitter vetch is ecologically adaptable to drought and has always been of interest due to its high nutritional value, short growing period, and ability to fix soil nitrogen. The research aims to investigate the effect of silicon as a signaling molecule in nutrient remobilization in bitter vetch to enhance yield.

In order to investigate the effect of potassium silicate levels (control (distill water), 2/1000, 3/1000, 4/1000 and 5/1000) on bitter vetch plant yield, an experiment was conducted in the form of a randomized complete block design with three replications at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. In this study, local seeds from Lorestan province were used. The seeds were manually planted at a depth of two centimeters in the soil in the first half of February 2022. The application of potassium silicate was carried out in two stages as foliar spraying. The first stage took place at the time of pod formation and 10 days after first application. At the end of the growth season, morphological traits including plant height, lowest pod hight, number of secondary branches in five plants, 1000- grain weight and yield traits were were measured and recorded. Statistical analysis was performed using the LSD method.

The application of potassium silicate significantly affected plant height, leaf canopy height, number of secondary branches, seed weight, seed yield, biomass, and harvest index. Silicon plays a role in strengthening the cell walls of stems and leaves, enhancing their physical strength, which can improve plant growth and light absorption by leaves, thereby stimulating plant growth. The results showed that the highest grain yield and biological yield in the foliar spraying treatment were 5/1000 and 4/1000 potassium silicate, which increased by 28 and 44%, respectively, compared to the control. In addition, the highest plant height, the number of branches and the weight of 1000- grain weight were observed in treatment of 5/1000 potassium silicate. The results showed that grain yield has a positive and significant correlation with the number of sub-branches (r = 0.51**), 1000- grain weight (r = 0.65**) and biological yield (r = 0.46**), respectively. In the present experiment, the positive and significant correlation of seed yield with the weight of 1000- grain weight and biomass shows that the process of transferring and distributing photosynthetic products to the reservoir is directly related to the source. The application of potassium silicate had a positive impact on various physiological processes, leading to increased biomass production and ultimately enhancing seed yield.

The application of potassium silicate significantly increased seed yield and had positive effects on various yield components of bitter vetch plants. Silicon application during the formation of sheath and sheath development enhances the translocation of photosynthetic materials to reproductive organs, ultimately improving plant performance.

In order to investigate the effect time and intensity of defoliation under use of amino acid condition, a factorial experiment was conducted based on randomized complete block design with three replications in Ali Abad Katoul, Golestan Province during growing season 2016-17. The first factor included the intensity of defoliation at three levels of 0, 50 and 100%, the second factor included the time of defoliation in five levels (V1, V3, V5, V7, and R1), and the third factor was the application and non-application of amino acids. The results showed that the effect of amino acids, the time and intensity of defoliation, and the interaction between times in intensity of defoliation were significant on oil yield. Application of amino acid resulted in an increase of 98.9% of oil yield compared to the non-application treatment. The highest oil yield was observed in the defoliation of 50% leaf in V1 stage with a mean of 867.5 kg/ha, which was 10.5% higher than to the control treatment. Comparing the mean interactions effects of times in intensity of defoliation, the highest grain protein yield was observed in defoliation of 50% leaf in V5 stage with 1296.17 kg/ha, which increased 17.33% compared to the control treatment. Defoliation of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf defoliation and the defoliation of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12.28% of grain yield compared to the non-application. In the interaction of the times in intensity of defoliation, the highest grain yield associated with 50% defoliation of leaf in stages V1 and V5 were 3681.9 and 3696.3 kg/ha respectively, which was 2.46 and 2.84% higher than to the control treatment, respectively. In general, leaf defoliation in late stages of growth (especially reproductive growth) with 100% intensity was reduced the quantitative traits (yield and yield components) and qualitative traits (oil and protein content of grain). On the other hand, the application of amino acids, by increasing the mean of measured traits, moderated the effect of defoliation stress.Defoliation of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf defoliation and the defoliation of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12.28% of grain yield compared to the non-application. In the interaction of the times in intensity of defoliation, the highest grain yield associated with 50% defoliation of leaf in stages V1 and V5 were 3681.9 and 3696.3 kg/ha respectively, which was 2.46 and 2.84% higher than to the control treatment, respectively. On the other hand, the application of amino acids, by increasing the mean of measured traits, moderated the effect of defoliation stress.Defoliation of 100% of leaves resulted in the lowest weight of 100 seeds, and the absence of leaf defoliation and the defoliation of 50% of the leaf had the highest mean of this trait. Application of amino acids increased 12.28% of grain yield compared to the non-application.

To evaluate effect of photosynthate availability under terminal heat stress on yield and yield components of wheat, this research was conducted in a split plot experiment based on randomized complete block design (RCBD) with three replications at the Research Farm of Islamic Azad University of Ahvaz in 2015 cropping season. Treatments were defoliation in four levels: removal of two upper leaves, flag leaf removal, complete removal of spikelet at one side of spike and control (non-manipulated) which assigned to main plots and three planting date including (Nov. 21st , Dec. 5st and Dec. 21st ) to subplots. Results showed that defoliation had significant effect on number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index at one percent probability level. Planting date also affected number of spike/m2, number of grains/spike, 1000 grain weight, grain yield, biological yield, and harvest index significantly at one percent probability level. The interaction effect of defoliation and planting date on the number of grains/spike, 1000 grain weight, grain yield, biological yield and harvest index was also significant. The highest grain yield (5691 kg.ha-1) belonged to the control treatment (no defoliation) at first planting date (Nov. 21st). This was due to the not coinciding filling periods to terminal heat stress of growing season where maximum assimilates were produced. The lowest grain yield (2123 kg.ha-1) belonged to delayed sowing and removal of spikelet at one side of spike. Maturity of plants during 3rd planting date (Dec. 21st) was coincided to heat stress and thus reduced assimilate production.

Although sink-source relation could be differed under drought tension conditions compared to optimum conditions, there are limited research with focus on this topic. In the present research, sink-source relation under drought tension conditions was investigated in a field experiment based on statistical randomized complete blocks design at College of Agriculture of Shiraz University during 2013-2014 cropping year. The treatments included irrigation regime at two levels normal irrigation and cutting off irrigation at flowering in main plots, Pishtaz, Chamran and Marvdasht wheat cultivars in sub plots and treatment of no defoliation and defoliation of all leaves except flag leaf at stem elongation and in flowering sub sub plots. The results showed that drought tension and defoliation decreased significantly ear length, grain number per ear, one-thousand grain weight, biological yield and grain yield as well as water productivity in all three cultivars. Delaying in leaf defoliation, reduced its negative impact on yield and yield components of wheat cultivars, so that defoliation at stem elongation and flowering stages was associated with 68.4 and 31.4 percent reduction in average of grain yield cultivars, respectively. Grain yield reduction in defoliation treatment at the time of stem elongation was due to reduction in grain number and in defoliation treatment at the time of flowering was due to grain weight reduction. Defoliation treatment, could compensate some losses in yield and yield components due to drought tension, in the other side, Chamran cultivar had the most tolerance to drought tension and defoliation; therefore, Chamran cultivar had better performance in such conditions. Due to higher tolerance of Chamran cultivar to drought tension and defoliation, use of this cultivar in the regions with wet limitations deserves long term explorations with more details.

Plants growth and development is depends on light energy of the sun. This energy thru photosynthesis is using for production of carbohydrates and other photo-assimilates. Part of produced carbohydrates is consuming by the same tissues for growth and development, while excess materials are trans -locates to other consumer or storage organs. Accordingly, plants parts are classified in source and sink organs. In order to improve crop yield by using relevant knowledge, this detailed review aimed to provide valuable information about biochemical and molecular mechanisms of production and consumption of photo-assimilates in different plant organs for breeding proposes. Source and sink strength like many other biological processes, are related to plant genetic potential, rate and type of plant response to environmental condition, efficiency of biochemical mechanisms and ability of involved enzymes in production and transporting photo-assimilates. This paper is intended to evaluate the recent advances in source and sink specifications, particularly in wheat. It has been attempted to identify indigenous attributes related to source and sink strength, determination of soluble carbohydrate production circumstances along with activity of involved key enzymes at different tissues, which might be suitable for increased plant performance, particularly in stressful environments like drought stress.

To investigate the effects of different levels of biofertilizer and phosphorus chemical fertilizer on quantitative and qualitative yield of forage corn cv. SC 540 under different humidity regimes, an experiment was conducted as Line Source based on randomized complete block design with three replications in Agricultural Education Center of Shahid Naseri in Karaj during 2012 and 2013. The implementation of Line Source was applied as four levels of irrigation (non stress, mild stress, moderate stress and severe stress). Phosphorus factor was in five levels including the application of 100% triple super phosphate fertilizer without biofertilizer, 75% recommended rate of chemical fertilizer with biofertilizer, 50% recommended chemical fertilizer with biofertilizer, 25% recommended chemical fertilizer with biofertilizer, biofertilizer and without chemical fertilizer. The results of experiment showed significant differences among the fertilizer treatments for most of studied traits in the first and second years. The highest fresh and dry forage yield were obtained from the treatment of 100% triple super phosphate fertilizer without biofertilizer that was not significally different from the treatment of 75% recommended chemical fertilizer and biofertilizer. Moisture stress reduced forage yield up to 21.22, 12.07 and 2.78 percent in severe, mild and very mild stress conditions in 2012, respectively. Treatment of 75% recommended chemical fertilizer and biofertilizer had also the highest effect on forage quality parameters. The findings of this research indicated that growth promoting bacteria exist in biofertilizer, in addition to growth increasemend and reduction of fertilizer consumption, lead to increase plant tolerance under water deficit stress conditions.

Wheat stem reserves can be an important contributor to grain particularly under decrease in the source strength through defoliation. The aim of this research was to study ability remobilization as important contribution on yield stability under drought conditions and to investigate their intrinsic compensatory mechanism in the wheat cultivars with different degrees of resource limitations under source limited conditions. To test this hypothesis، two separate field experiments were carried out at research field of university college of Agriculture and Natural Resources، university of Tehran (located in Karaj) during 2010-2011 growing seasons. First experiment was carried out in a split plot design based on RCBD that included 36 wheat cultivars and different levels of defoliation (non-defoliated control (ND)، removal of all leaves (FD)، removal of all leaves except the flag leaf (PD)) and the Second experiment as a randomized complete block design that included 36 wheat cultivars and chlorophyll desiccation. The plants were defoliated and desiccation in 15 day after flowering growth stage. The result showed that removal of all leaves except the flag leaf (PD) and all leaves (FD) caused reduction of grain weight by 8% and 22%، respectively. Also highest grain yield were obtained of Fongh cultivar in PD and FD treatment. Generally cultivars with higher accumulation were less affected by defoliation treatments. Wide ranges of remobilization were detected between cultivars and highest remobilization was obtained of Crossed Shahi cultivar. Contribution of stem reserves to grain yield was by 36%.

Studies manipulating the source-sink relationships during post anthesis in wheat have shown inconsistent results، concluding that wheat yield could be either sinkor source-limited. The aim of this study was to determine source limitation degree of 36 Iranian wheat cultivars andto investigate their intrinsic compensatory mechanism in response to source size reduction. A split plot design based onrandomized complete block designwas carried out with 3 replications. Treatment included 36 wheat cultivars and different levels of defoliation (non-defoliated control(ND)، removal of all leaves (FD)، removal of all leaves except the flag leaf (PD)). Defoliation was carried out at flowering stage. A wide range of responses to defoliation treatments observed among the cultivars، suggesting a high variation in sink or source limitation among the cultivar while them were cultivars with no response sever leaf defoliation (FD) same cultivars different even by mild leaf defoliation (PD)، thatimplying to possible various compensatory mechanism in cultivars.

To study the effect of source and sink limitation on grain yield and yield components of three genotypes of rice under different levels of nitrogen fertilizer a field experiment was conducted at Sari Agricultural and Natural Resources Sciences University, Sari, Iran, in 2009 growing season. Experiment was arranged as split-split-plot in randomized complete block design with three replications. Three levels of nitrogen fertilizer (0, 46 and 92 kg N.ha-1) were assigned to main plots; three rice genotypes (Jelodar, Danesh and Jahesh) as sub-plots and four levels of source-sink limitation (control, removal all leaves except flag leaf, flag leaf removal and removal of 1/3 end of panicle) in sub sub plots. Results showed that three genotypes had both source and sink limitations. Nitrogen fertilizer, however, could compensate sink limitation to some extent especially in optimum nitrogen level (46 kg N.ha-1) by increasing photosynthates remobilization. The findings of this research indicated that flag leaf contributed about 22.61% in grain weight. Flag leaf had the highest efficiency in 92 kg. N.ha-1, and other leaves had higher efficiency in 46 kg.N.ha-1 in grain yield improvement. Furthermore, by imposing source limitations (particularly removal all leaves except flag leaf) greater variation in 1000 grain weight was observed in genotypes which had greater grain size (e.g. Danesh). Nitrogen× genotype interaction indicated that Jelodar genotype had the lightest grain yield with 8478 kg.h-¹ in 92 kg.h-¹ of nitrogen fertilizer level. Nitrogen× genotype interaction was significant for harvest index and Danesh genotype showed the highest harvest index (57.8%) in 46 kg.h-¹ of nitrogen fertilizer level.

In order to determine, source of grain yield limitation under different enviromental conditions, as well as indentifying the rate of restrication caused by terminal heat stress on development and growth of wheat, this research was conducted with twenty wheat genotypes using Randomized Complete Block Design (RCBD) with three replications, in two separate experiments in two years(1998-2000). The experiments were sown in late of december and january to stimulate favoarable and unfavourable conditions, respectively. Five to seven days after anthesis flag leaf and spikelets from one side of spike were removed to stimulate, sink and source limitation respectively. Aftert harvest, source and sink restrication percentage were calculated according to the mean of remaining grains in treated spike and control (without removal of flag leaf and spikelets). Results indicated that all genotypes had not sink restrication and the contribution of flag leaf to grain dry weight was 12%. However, some genotypes showed source restrication. This restrication was estimated from 0 to 34% (mean: 12.6%) and 5.7 – 41.2% (mean:17.2%) for favourable and unfavourable conditions, respectively. Therfore, source restrication caused by exposure to terminal heat stress was greater by 6%. Likewise, results indicated that source restrication was higher in genotypes with large grain size. Grain weight had not significant effect in the determination of final yield. Reduction in grain yield must be sought in other yield components, such as grain number per spike and spikes number per sqaure meter.