Effect of Organic Particulate Matter on Vegetable Crops and their Control Potentials

Air pollution has an impact, include impact to the plants. The adverse effects of air pollution have been associated with three major sources. They are gaseous pollutant and particulates from fossil fuels, manufacturing plants and vehicles. Many studies reveal that plants absorb particulate pollutants can cause damage or decline in growth. This study analysed the effects of organic particulate matter exposure on vegetable crops that were lettuce (Lactuta sativa L) and cucumber (Cucumis sativus L). Thus from the research we can control vegetable crops from particulate matter pollution. Growth parameters include the number of leaves, plant height, fresh weight, dry weight, number of chlorophyll and stomata index. This research was conducted on Padjadjaran University Greenhouse, Jatinangor. Lettuce and cucumber were given three treatment, those were: plant was contaminated with organic particulate matter derived from clay, plant inside and outside the chamber were not contaminated. The results showed that organic particulate matter exposure more affects the growth of lettuce than cucumbers for the following parameters: plant height, dry weight and fresh weight. Control potentials of organic particulate matter include regulation management, reducing field burning of vegetable residue, and implementation of particulate matter control devices in industry and vehicles.

Air pollution has an impact, include impact to the plants. The adverse effects of air pollution have been associated with three major sources. They are gaseous pollutant and particulates from fossil fuels, manufacturing plants and vehicles. Many studies reveal that plants absorb particulate pollutants can cause damage or decline in growth [18][19][20][21][22][23].
In order to provide appropriate air pollution controlling in horticulture crops, we analysed the effects of organic particulate matter on vegetable crops that were lettuce (Lactuta sativa L) and cucumber (Cucumis sativus L). The objective of the research was to analyze the effects of exposure of organic particulate matter on growth of lettuce (Lactuta sativa L) and cucumber (Cucumis sativus L) both morphology and physiology thus from the research we can control vegetable crops from air pollution.
Air pollution controlling on vegetable crops is one of the solution to mitigate vegetable quality and production. Good quality of vegetable crops will directly stimulate healthier society thus may results in developing low carbon society.

Area of Study
This research was laboratory scale and was conducted on Padjadjaran University Greenhouse, Jatinangor, Sumedang District, West Java, Indonesia. It is located at 723 meters above sea level. The climate of the area is relatively temperate with an average rainfall of about 2500 mm. The highest temperature recorded was 19 0 C-27 0 C.

Experimental Setup
Lactuca sativa L and Cucumis sativus L were given three treatment, those were: plant was contaminated with organic particulate matter derived from clay, and plant inside and outside the chamber were not contaminated.

Air Pollution Monitoring
Pollutant parameters measured in the chamber contaminated with organic particulate matter derived from clay was PM10. PM10 was monitored every 15 minute of 120 minute intervals for 4 (four) weeks.

Plant Sampling and Analysis
Plants were grown under field conditions in Green House. Plant samples were analysed every 7 days of intervals for 4 (four) weeks. Growth parameters include the number of leaves, plant height, fresh weight, dry weight, number of chlorophyll and stomata index. ANOVA was used to determine the significant difference between treatments for the different variables and the Least Significant Difference (LSD) test at the 95% probability level. All the statistical tests were performed using SPSS software (SPSS Inc., version 10).

Stomata Observation
Observation of leaf structure and stomata using light microscope with 400x enlargement and using Scanning Electron Microscope (SEM) was performed at Instrumentation Laboratory in ITB.

Concentration of Particulate Pollutants
The chamber was contaminated with clay, pollutant parameters measured was PM10. The results of particulate concentrations are shown in Table 1. During the exposure period, particulate concentration in clay chamber tends to be higher than the measured control levels both control inside or outside. Maximum particulate concentration was found at second week (1.677,78 µg/m 3 ).

Growth Response
The results of growth response of PM10 exposure to the plant are shown in Table 2 & Table 3 and Figure 3.. Plant growth parameters were plant height, number of leaves, plant fresh weight and plant dry weight. difference on number of leaves from four treatments. Particulate exposure was significant (P < 0.05) on decrease of plant fresh and dry weight of Lactuca sativa L compared to control outside rather than control inside (Sig 0.000 < 0.05). Based on statistical study, there was no effect of particulate exposure on reduction on growth of Cucumis sativus L (P < 0.05).

Physiological Response
Physiological parameter was number of chlorophyll and stomata index. The results of physiological response of both plants to particulate exposure are shown in Figure 4 and Figure 5. According to the study, there were no effect of particulate exposure on reduction on number of chlorophyll and stomata index of both plants during the particulate exposure period compared to control outside and control inside chamber.

DISCUSSIONS
Based on study, particulate exposure was significant (P < 0.05) on decrease of plant height, plant fresh and dry weight of Lactuca sativa L compared to control outside rather than control inside (Sig 0.000 < 0.05).
Previous studies have been done on pollutant for damaging effect to the plant. The main responses are morphological and on the development of flowers and fruit [24]. Another study concludes that excess substance become toxic to the plant. This caused leaf chlorosis and root browning. Greater toxic substance concentration in the nutrient solution along with the appearance of toxicity symptoms significantly depressed the fresh mass of leaves, stems and roots [25]. Phosphate and nitrogen are plant nutrient in small quantities; excess nutrient will damage the plant. There is a complex change in physiological response due to excess substance. Plant cell may cause lysis and damage. Naama et.al on their study on fungal spores showed the allegenicity since the fungal spores were exposed to air pollution. This is due to protein nitration and deamidation [26].
Plants are the primary receptors for pollutants in the atmosphere including particulate matter. This is due to huge foliar surface area in the upper epidermis of the leaves that acts as natural sink for pollutant. The harmful effects of pollutant especially particulate matter on vegetation have already been note by many researchers [27][28][29][30][31][32][33][34][35][36]. From previous study, it showed that vegetation is an effective indicator of impact of air pollution especially particulate matter.
Based on study, the particulate exposure more affects the morphology of Lactuca sativa L than Cucumis sativus L. Impact of pollutant depends on the concentrations of elements in the chamber and the physiological status of the plant. Previous study showed that phytotoxicity level of plant due to environmental contamination as follows: Z. mays < C. sativus < L. sativa L. The results indicate inhibition in root elongation as the most sensitive toxicity end point for L. sativa L [37]. This study conclude that C. sativus L was tolerant vegetable to particulate pollutant than L. sativa L. The studies of the responses of species to air pollutants for their tolerance or sensitivity has been done by Gao et al. (2016); Mukherjee and Agrawal, (2016); Singh et al., 1991;and Wen et al.,(2004) [38][39][40][41].
Based on study, we may conclude that there was effect of the particulate pollutant to vegetable crops especially on the sensitive vegetables. Vegetable planting should consider air pollution controlling in order to maintain and enhance vegetable productivity. In Indonesia, air pollutants are the products of combustion from industrial area and transportation sectors which is currently developing. Olivier et.al (2016) reported that Indonesia (currently with a share of 1.4% of the global total CO2 emissions) showed a 4.0% increase in CO2 emissions in 2015, compared to 2014. These CO2 emissions derived from power and heat generation, other energy industry own use, manufacturing industry, road transport, other transport, residential sector, and other buildings [42]. Therefore, air pollutant controlling on vegetable crops include setting vegetable crops land away from industrial area and transportation sectors.
In Indonesia, the farmers used to burn crops residue after harvesting, therefore it may increase air pollutant exposure. Agricultural activities are the major human source of air pollution in rural areas. Majra (2011)  Technologies are available for harnessing energy from crop residues are direct combustion, gasification, carbonisation, ethanol production, liquefaction, bricking and pyrolysis [44]. Other researchers suggest using agricultural residues as feedstock for biofuel production [46][47].
Author thanks to Ministry of Education, Republic of Indonesia, for Collaboration Research With Foreign Researcher and International Publication and Faculty of Environmental Engineering ITB.