Journal of Spatial Analysis

 Investigating the effect of desert micro-organisms on vegetative traits and yield of grapevine in Shiraz
 
Extended Abstract
 
Introduction
 Mineral aerosols as a pollution of atmosphere has become a global concern with environmental impacts on human, Vegetable and transportation system. Plants exposed to aerosol exhibit morphological and physiological changes. Dust particles is one of the aerosols in the atmosphere which deposits on the leaf of plants can alter their available light of photosynthesis. This interferes with gas exchange of CO₂ between the leaf and air of environment, and the reduction of leaf stomatal conductance. Finally reduction the yield of plants. Grapevines Vitis vinifera. Askari, are grown extensively in the Shiraz city. The period from March to July coincides with extensive shoot and fruit which these processes depend on environment conditions. Any stress reducing fruit set and leaf characterizes, will negatively affect grapevine productivity. Thus, the objective of this study was to examine the effects of dust deposits on grapevine leaves and to estimate the impact on vegetative traits and yield of grapevine.
 
Method
 Experiments were implemented on 36 grapevines V.vinifera L. cv. Askari in the form of RCBD with drip irrigation during 2017-2018 from late March to July when the buds grow until the harvest. Treatments included: T₁) artificial dust sprayed on canopy of vine by a manually operated duster, T₂) washing canopy of vines using well water in the field after spraying artificial dust, and T₃) control. Artificial dust particles were collected from uncultivated areas of Azadegan plain in Khuzestan province. To provide suitable fine particles, the soil was grinded, milled and sieved using a mesh size of 200 opening per inches. The physical and chemical tests were performed using an X-ray diffraction device. A dust chamber and a dust generator were constructed to simulate dust. A mechanical apparatus consisted of a 50-cm pipe and a ventilation fan was also used. The chamber was made of a plastic sheet with 2×2×1.5 m dimensions. To evaluate chlorophylls a and b concentration, used by spectrophotometer in wavelengths of 647 nm and 663 nm. Single Leaf Area Index (LAI) was calculated by image processing method Win-Area-Ut_10 system. The sugar content of grapes was determined by measuring the Refrectometer BME center index of their juice sugar. Also measured the RWC, fruit set percentage, Length of Branch Leaf Dry Weight and Yield.
 
Results
The mean of particle size was 10.6 μm and the chemical composition of these particles included Silicon Oxide, Sodium Sulfate, Na = 6.14 mg/L, K = 10.73 mg/L, Ca = 23.9 meq/L and Mg = 3.5 meq/L. Chlorophyll a and b content decreased by dust particles treatment in the throughout the phonological stages of grapevine and had a significantly different as compared to washing and control treatments. RWC was reduced in the dust treatment as compared to the washing and control treatment (P < 0.05). The maximum of Leaf Area Index (131 cm²) was obtained in the control and the minimum (86 cm²) was obtained in the dust treatment. The maximum percentage of fruit set was obtained in the washing treatment (24%). but, the lowest fruit set trait (18%) was found in the dust treatment. The highest TSS (22.7 %) was observed in the washing treatment and the lowest TSS (18.1%) was seen in the dust treatment. The difference among the numbers of berries among treatments was significant (P < 0.05). The highest and the lowest numbers of berries were observed in the washing treatment (87 berries per bunch) and the dust treatment (49 berries per bunch). The heaviest bunch was observed in the washing treatment (158.7 g), while the lightest bunch weight (100 g) was observed in the dust treatment which had significantly difference with control and washing treatments. The highest yield (22.5 kg/vine) was observed in the washing treatment and the lowest yield (7.9 kg/vine) was observed in the dust treatment, whereas control produced 19.5 kg/vine averagely.
 
Conclusion
It was found that dust accumulation on the surface of leaf grapevine Askari induces some physiological changes such as a reduction of photosynthetic pigments, relative water content and leaf area. Deposition of dust particles on flower of grape led to decrease of reproductive trait, but washing vine by water led to improvement of production. As a result, washing of vine also increased grape production as compared to the control treatment. According to the results, dust particles reduced fruit set by deposition on flower and they were identified as an environmental stress on grapevine. More importantly, the results revealed that yield of grapevine was adversely affected by dust deposits over a short interval of time during the fruit set. Therefore, the fruit set stage, in which the fruit is formed, was recognized as the most important stage in plant production. It was also found that removal of dust particles from the plant leaves by washing methods can reduce the effects of dust particles.
 
Keywords: Dust, Chlorophyll, Fruit, Sugar, Shiraz.