Application of Silica Gel on Growth and Yield of Camelina sativa L

Article History Received: July 29, 2020 Revised: October 20, 2020 Accepted: October 29, 2020 The present study was designed to evaluate the effect of different concentrations of Silica gel on the growth and yield of Camelina sativa. A pot experiment was laid out in Completely Randomized Design (CRD) with three replications at Nanotechnology Laboratory, Department of Agronomy, PMAS Arid Agriculture University Rawalpindi. The experiment consisted of 4 levels (0.15 mg/g, 0.30 mg/g, 0.45 mg/g and 0.60 mg/g) of each mentioned nutrient along with control. The data were recorded and analyzed according to recommended procedure for following parameters viz., germination %, root and shoot length (cm), root and shoot biomass (g), relative water content of leaf and leaf membrane stability index. It was observed that 0.60 mg/g silica gel application increased the seed germination (80%), root length (6.67) cm, shoot length (35.33) cm, root biomass (1.7) g, shoot biomass (5.57) g, relative water content of leaf (0.69) and leaf membrane stability index (0.07). The study concluded that significant effect of silica gel application is crucial and important to improve vegetative attributes of false flax.


INTRODUCTION
Agriculture is the backbone of country's economy and plays vital role in economic growth and development. Oilseed crops contribute second highest share in Pakistan's economy after cereals (Bayer, 2010). Edible oil is used in daily household and commercial food preparation as an important and essential ingredient across the country. Unfortunately, our agriculture based economy is unable to meet the domestic edible oil production locally. The deficiency is now progressing at alarming rate due to rapid increase in population ( (Abbas et al., 2010). Camelina (false flax / gold of pleasure) scientifically termed as Camelina sativa L. is an oil seed crop of brasicaceae family (Wariach et al., 2013) with low agronomic-input use (Putnum et al., 1993). It has the unique and health favored fatty acid patterns, composed up of higher level linolenic acid and comparatively low erucic acid concentration (Zubr and Matthaus, 2002). The oil extracted from seed is the key product from Camelina, which vary among cultivar 320 and 460 g kg -1 (Vollman et al., 2007). Camelina seed meal fluctuates from 390 to 470 g kg -1 for Crude protein content  and glucosinolates varies between 13.2 and 36.2 mmol g -1 dry seed (Schuster and Friedt 1998). Moreover, the Camelina has economically feasible oil content percentage range from 38 to 43% and protein content range from 27 to 32% (Gugel and Falk, 2006). The health friendly oil properties of Camelina sativa could be evaluated by the fact oil contains omega-3fatty acid, a potentially rich substance to lower down cholesterol level (Korvenon et al., 2002). In North America, it was mainly known as a wild flax (Lafferty et al., 2009). The agronomic and breeding potential of this crop has not been fully examined (Hunter and Roth, 2010). It is resistant to draught (Kyung et al., 2013), and also cold resistant (McVay and Khan, 2011), effective user of nutrients, and a short duration crop. The camelina's oil is equally beneficial for humans as well as animals. Due to low cultivation cost and rich in oil content, also been used quiet often in biofuel industry (Agarwal et al., 2010). Our today knowledge of advance and modern cropping system along with new oil seed crops, accelerates our interest in Camelina sativa (Rehman et al., 2014). Camelina sativa is an annual crop which can be cultivated in both, summer and winter seasons. Depending over nutrient availability the height of the plant is around 60 cm to 100 cm. There is no dormancy of seeds (Ehrensing and Guy, 2008). However, the plant is comparatively more disease susceptible and potentially les competitive to weeds sown in winter (Zubr, 1997). Moreover, the plant is unable to perform well on wet or poorly drained soils, which favors disease incidence (Hunter, 2010). The crop could be successfully grown on variety of soils. However, heavy, water logged, acid soils and lands having severe weed problem are not suitable for Camelina sativa cultivation (Lo ák et al. (2011). Comparatively with rapeseed, it is more resistant undesirable climatic conditions primarily drought and low temperature (Vollmann et al., 2007). Moreover, camelina sativa pods are shatter free a unique character which makes it the best choice for mechanical harvesting. The soils of Pakistan are mostly dry with less organic matter (0-1%), high concentration of calcium carbonate and a low concentration of organic matter. That calcium carbonate makes our soil alkaline with pH 8 or above. So use of the balanced nutrients for optimum yield is necessary (Khan, 2003). High yielding and good quality of Camelina sativa production mostly depends on balanced nutrition and growing condition. In our country, the farmers are only focusing on fertilization of macronutrients NPK, while neglecting the importance and essentiality of micronutrients (Rashid and Rafiq, 1998). Low quantity of micronutrients required by plant, but their deficiency affects all fundamental biochemical and physiological process and reduce the crop yield (Imtiaz et al., 2010). Silicon (Si) has not been proven to be an essential element for higher plants, but its beneficial effects on growth have been reported in a wide variety of crops, including rice, wheat, barley, and cucumber. Si is especially important for healthy growth and high and sustainable production of Camelina sativa, which is a typical Si-accumulating plant. Si fertilizer is applied to crops in several countries for increased productivity and sustainable production. Plants take up Si in the form of silicic acid, which is transported to the shoot, and after loss of water, it is polymerized as silica gel on the surface of leaves and stems. Evidence is lacking concerning the physiological role of Si in plant metabolism.

Leaf Membrane Stability Index (LMSI)
It was calculated further by following the methodology proposed by George, et al. 2015. For this, two leaf strips of 0.1 g from plants of each treatment were taken and put into a test tube having 10ml distilled water. One test tube e.g sample 1, was kept in water bath at 40 o C for 30 minutes and its electrical conductivity e.g C1 was calculated. Second test tube containing sample 2, was kept in boiling water bath at 100 o C for 15 minutes and its electrical conductivity e.g C2 was calculated. This process was repeated for all treatments and LMSI was calculated as follows. Leaf Membrane Stability Index (LMSI) = 1-(C1/C2) 100

RESULTS AND DISCUSSION Germination Percentage
Analysis of Variance (ANOVA) for germination count of Camelina sativa showed significant difference among various treatments (figure 1). The highest germination (80%) count was recorded in treatment where, 0.45 mg/g silica gel was applied. Moreover, the T5, 0.60 mg/g silica gel (76.67%) and T3, (73.33%) followed by T2 (63.33) while the minimum germination count was recorded in control treatment (53.33%). The graphical analysis is shown in figure 1.

Root Length (cm)
Analysis of Variance (ANOVA) for root length of camelina sativa plant studied under pot experimental condition indicated that all treatments possessing highly significant differential capability for affecting root length. Analysis of means values (LSD), at 5% level of significance, indicated that highest mean value (6.76) root length of Camelina plant was recorded in treatment 5 comprising the application by 0.60 mg/g silica gel.
Moreover, the least mean value (4.07) was recorded in control. The range for number of siliquae per plant is 5.16 to 4.76 and 3 distinct classes were formed for root length per plant. The graphical analysis is shown in figure 2.

Root Biomass
Root biomass of Camelina sativa was significantly affected by silica gel application. The maximum root biomass of plants was observed in treatment 5 where 0.60 mg/g silica gel (1.7) g. The minimum root biomass was visible in control (0.85) g. Rest of the treatments produced plants with heights range of (1.34 to 1.06) g.
The maximum root biomass gained in T5 could be due to balance availability of required element. The graphical analysis is shown in figure 4.

Shoot Biomass
Highest mean value (5.57) for shoot biomass was recorded in treatment 5 comprising the silica gel application by 0.60 mg/g. Moreover, second highest mean value (4.63) treatment 4 comprising of 0.45 mg/g silica gel application respectively. The least mean value (3.33) was recorded in control depriving of silica gel application. The range for shoot biomass is 4.3-4.03 and 2 distinct classes were formed. The graphical analysis is shown in figure 5.  Relative Water Content of Leaf (RWC Highest mean value (0.6983) relative water content of leaf was recorded in treatment 5 comprising the silica gel application by 0.60 mg/g. Moreover, second highest mean value (0.5133) treatment 4 comprising of 0.45 mg/g silica gel application. The least mean value (0.27) was recorded in control depriving of silica gel application. The range for relative water content is 0.4633-0.3767 and 2 distinct classes were formed for relative water content of leaf. Similar results were observed by George, et al. 2015 in which effect of water stress in tomato was studied. The graphical analysis is shown in figure 6.

Leaf Membrane Stability Index (LMSI)
Highest mean value (7.07%) relative water content of leaf was recorded in treatment 5 comprising the silica gel application by 0.60 mg/g. Moreover, the least mean value (4.30%) was recorded in control depriving of silica gel application. The range for relative water content is (6.23 to 6.17%) and 2 distinct classes were formed for relative water content of leaf. Similar kind of observation was observed by George, et al. 2015 in which effect of leaf membrane stability index in tomato was studied. The graphical analysis is shown in figure 7.

CONCLUSION
The study concluded that significant effect of silica gel application is crucial and important to improve vegetative attributes of false flax. Application of silica gel significantly increased the seed germination (80%), root length (6.67) cm, shoot length (35.33) cm, root biomass (1.7) g, shoot biomass (5.57) g, relative water content of leaf (0.69) and leaf membrane stability index (0.07).