Influence of Silicon Fertilization on Maize Performance Under Limited Water Supply

Transcription

1 Influence of Fertilization on Maize Performance Under Limited Water Supply Muhammad Amin, Riaz Ahmad, Anser Ali, Iqbal Hussain, Rashid Mahmood, Muhammad Aslam & Dong Jin Lee ISSN X DOI /s x 1 23

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3 DOI /s x ORIGINAL PAPER Influence of Fertilization on Maize Performance Under Limited Water Supply Muhammad Amin 1 Riaz Ahmad 1 Anser Ali 2 Iqbal Hussain 1 Rashid Mahmood 3 Muhammad Aslam 1 Dong Jin Lee 4 Received: 7 February 2015 / Accepted: 8 October 2015 Springer Science+Business Media Dordrecht 2016 Abstract (Si) is a naturally occurring beneficial nutrient which modulates plant growth and development events and has been known to improve the crop tolerance to abiotic stresses. A pot experiment was conducted during 2011 at the Postgraduate Research Station (PARS), University of Agriculture Faisalabad, Pakistan. We evaluated growth of two maize hybrids P-33H25 and FH-810 under well watered and water deficit situations as affected by Si application. was added in 100 mg/kg. Plants were grown with two levels of soil water content viz. 100 % and 60 % of field capacity. Water deficiency in soil significantly reduces agro-morphological and physiological attributes of maize plants. In drought-stressed plants of hybrid P-33H25 and FH-810 silicon application significantly increased plant height ( cm and cm), stem diameter (1.23 cm and 1.22 cm), number of leaves (13.26 and 13.20), cob length (13.96 cm and cm), number of grains/cob ( and ), 100 grain weight (19.65 g and g), grain yield (46.18 g and g) and biological yield ( g and g) along with Anser Ali uafanser@gmail.com 1 Department of Agronomy, University of Agriculture, Faisalabad, Pakistan 2 Department of Agronomy, Ghazi University, Dera Ghazi Khan, Pakistan 3 Institute of Agricultural Sciences, University of Punjab, Lahore, Pakistan 4 Department of Crop Science and Biotechnology, Dankook University, Suji-gu, South Korea improvement in photosynthetic rate and lowered transpiration rate, respectively. In conclusion, silicon application to drought stressed maize plants improved the growth and yield which could be attributed to improved photosynthetic rate and lowered transpiration. Keywords Water deficit Maize hybrids Yield Gas exchange 1 Introduction Although Si is not generally included in the list of essential elements, it is considered as one of the important beneficial nutrients for plant growth [1]. The amount of Si in soil may vary considerably from 1 % to 45 % [2]. However, Si is present in soil in different forms, but plants can easily absorb silicic acid Si(OH) 4 from soil. Silicic acid is generally found in the range of mm in soils [3]. Although Si is beneficial for plant growth it plays a vital role as a physico- mechanical barrier in most plants. Despite its deposition on cell walls, its active involvement in a multitude of physiological and metabolic processes is also evident [4, 5]. Plants deprived of Si often show poor development and reproduction, but it depends on the type of plant species. In general, plants belonging to the family Gramineae accumulate much more silicon than that by other species belonging to other families. It has also been reported that most dicot plants absorb Si passively but legumes can efficiently exclude Si from their roots [6]. However, in rice, a known Si accumulator, uptake and transport of Si takes place through an active process [7]. Drought stress is one of the most devastating stressful environments for plant growth and production [6, 7]. One

4 viable strategy of overcoming the drought-induced injurious effect on plant growth is the exogenous application of inorganic nutrients [8]. By adopting this strategy, studies [9] have recommended the supplements of Si to plants subjected to salt affected soils, and addition of Si has been considered beneficial for improving crop tolerance to both biotic and abiotic stresses [10, 11].The ameliorative role of Si to adverse effects of drought has been examined in different crops e.g., rice [12], sugarcane [13], wheat [14], tomato [15], sorghum [16] and soybean [17]. The hypothesis was whether the increased drought resistance by Si is mediated via the improved photosynthetic rate and lowered transpiration in drought stressed maize crops. Nonetheless, the purpose of the present study is to provide further information on exogenous use of Si and its ability to counter water deficiency inhibitory effects in maize hybrid crops. 2 Materials and Methods The experiment was sown on 10 February, The physico-chemical soil analysis and atmospheric data during the studyis given in Tables 1 and 2, respectively. The design in this experiment was completely randomized (CRD) with factorial arrangement replicated thrice. Three extra replications were also conducted to obtain the gas exchange data at the vegetative and reproductive stage. A fertilizer dose of 1.25g kg N and 0.625g K 2 O and g P 2 O 5 /pot was applied. All the P, K and 1/3 of the N fertilizer were applied before sowing. Remaining the N was applied in two splits. Six seeds of each of the hybrids were sown in each pot. Before sowing seeds were treated with suitable fungicide and insecticide. After sowing of seeds all the pots were irrigated fully. On every day each pot was irrigated with the required amount of water on visual observation of the Table 1 Physico-chemical properties of soil used in the study Soil characteristics Unit Value Soil textural class Sandy clay loam Sand % 57 Silt % 20 Clay % 23 Field capacity % ph 8.11 EC dsm O.M % 0.87 CaCO 3 % 2.11 P (available) ppm 7.82 EC= Electrical conductivity, O.M. = Organic matter, P= phosphorus soil. At the four leaf stage thinning was done to keep four plants per pot but after the vegetative data (45 DAS i.e. days after sowing) of gas exchange only two plants per pot were maintained until physiological maturity. Drought stress was imposed three weeks after germination until maturity by maintaining 60 % field capacity (FC) with the help of a moisture meter (Delta-T device, Cambridge, UK). The crop was harvested when fully mature and standard procedures were followed to record the data. There was soil application of silicon (100 mg/kg) in the form of calcium silicate after dissolving it in KOH at 71 C[18]. Harvesting was done at physiological maturity of the crop. Determination of field capacity The field capacity was determined on a gravimetric basis (Nachabe, 1998). For determination of field capacity three samples of 200 gm each of the soil used in the experiments were taken at the time of filling the earthen pots (24.6 cm diameter and 28 cm deep). These samples were then incubated at 105 C for 24 hours and oven dried samples were weighed and averaged for determination of total moisture content of the soil at the time of seed sowing. Then the saturation percentage of three samples of 100 gm each of this oven dried soil was approximated by measuring and averaging the distilled water used in making a completely saturated paste of three samples. The field capacity was determined by using the following formula: Field capacity = Saturation percentage/2 For pot experiments the field capacity of each pot was maintained as per treatment. Soil moisture percentage of each pot was measured on a daily basis with the soil moisture meter. Each time pots were irrigated to maintain field capacity level. This procedure was carried out up to the assessment of seedlings. 2.1 Agronomic Attributes Various agronomic attributes were recorded in this study like plant height, stem diameter, leaf area, cob length, grains per cob, 100-grain weight, grain yield and biological yield per plant. 2.2 Gas Exchange Observations The various leaf gas exchange parameters (Photosynthetic rate (μmol/m 2 /s) and Transpiration rate (mmol/m 2 /s)) were estimated with the help of an open system LCA-4 ADC portable infrared gas analyzer (Analytical Development Company, Hoddeson, England). Observations were made on third leaf from the top of plant that was fully expanded and youngest in the morning time from 8:00 a.m. to 10:00 a.m. The following adjustments were carried out to take observations: leaf chamber temperature varied from C,

5 Table 2 Atmospheric data during study period Month Temperature ( C) Relative humidity (%) Rainfall (mm) February March April May surface area of the leaf was 6.25 cm 2,ambientCO 2 concentration was 371 μmol mol 1, ambient pressure into chamber was kpa, Photosynthetically active radiations (PAR) at the surface of leaf were maximum up to 770 μmol m 2 s 1, leaf chamber volume gas flow rate was 296 ml min 1 and molar gas flow rate into the chamber was 400 μmol s Statistical Analysis Data collected were analyzed statistically using Fisher s analysis of variance technique. Difference among the treatments means was compared using the least significant difference test at 5 % probability level [19] using the MSTAT C computer software. 3Results 3.1CropGrowthandYieldAttributes Growth and yield attributes of maize hybrids like plant height, stem diameter, leaf number, cob length, number of grains per cob, 100 grain weight, grain yield and biological yield were found to be adversely affected by drought in the present study (Table 3 4). However, silicon application significantly improved these plant attributes. Plant height was drastically affected in both maize hybrids when plants were grown under the water deficit condition (Table 3). Maximum plant height ( cm) was observed in silicon treated well watered plants of maize hybrid P-33H25 followed by silicon mediated well watered plants of FH-810 ( cm). However, short statured plants (88.03 cm) were found in hybrid FH-810 where plants were grown under limited moisture supply without silicon treatment. Under the water deficit environment (60 % FC) more reduction in plant height (57.59 cm) was observed in hybrid FH-810 (drought sensitive) while hybrid P-33H25 (drought tolerant) showed a reduction of cm. fertilization considerably increased this growth attribute in both maize genotypes under optimal and abridged moisture supply. The plant height was increased by 23 cm and 32 cm with silicon application with respect to without silicon nutrition for maize hybrids P-33H25 and FH-810, respectively under drought condition i.e. 60 % FC (Table 3). treated plants of maize hybrids P-33H25 and FH-810 produced thicker stems that were either grown under well watered i.e. 100 % FC or limited moisture supply i.e. 60 % FC (Table 3). Maximum stem thickness was found in silicon treated well watered plants of both maize genotypes. However, drought stress severely reduced stem thickness. There was a reduction of 0.27 cm in both maize hybrids due to the water deficit. However, application of Table 3 Influence of silicon application on agronomic traits in maize under well watered and moisture deficit condition Hybrids Drought Plant height (cm) Stem diameter (cm) No. of leaves Cob length (cm) P-33H % FC 0 mg/kg bc 1.41ab 13.91b 15.98b 100 mg/kg a 1.47a 14.85a 17.20a 60 % FC 0 mg/kg f 1.14de 12.99d 12.04f 100 mg/kg d 1.23cd 13.26cd 13.96d FH % FC 0 mg/kg c 1.33bc 13.61bc 15.17c 100 mg/kg b 1.37ab 13.92b 16.03b 60 % FC 0 mg/kg 88.03g 1.06e 12.50e 10.35g 100 mg/kg e 1.22d 13.20d 12.83e LSD value Values sharing the same letter in a column do not differ statistically at P FC = Field capacity, LSD = Least significant difference

6 Table 4 Influence of silicon application on yield and yield related traits in maize under well watered and moisture deficit condition Hybrids Drought number of 100-grain grain yield/plant biological grains/cob weight (g) (g) yield/plant (g) P-33H % FC 0 mg/kg b 21.34bc 54.91bc bc 100 mg/kg a 22.86a 63.95a a 60 % FC 0 mg/kg e 17.83f 35.49f e 100 mg/kg c 19.65d 46.18d d FH % FC 0 mg/kg b 20.84c 53.10c c 100 mg/kg b 21.69b 57.17b b 60 % FC 0 mg/kg f 16.23g 29.95g 83.03f 100 mg/kg d 18.51e 39.88e e LSD value Values sharing the same letter in a column do not differ statistically at P 0.05 FC = Field capacity, LSD = Least significant difference silicon brought an improvement of 0.09 cm and 0.16 cm in stem girth of drought stressed plants of hybrids P-33H25 and FH-810, respectively. Water deficit conditions resulted in a reduction in leaf number of hybrids i.e. P-33H25 (12.99) and FH-810 (12.50). treatment did not affect the number of leaves in drought stressed plants of maize hybrid P-33H25. However, silicon treated drought stressed plants of hybrid FH-810 produced more leaves (Table 3). The maximum cob length (17.20 cm) was reported in silicon mediated well watered plants of hybrid P-33H25 while the minimum (10.35 cm) was in drought stressed plants of hybrid FH-810 that were grown without silicon nutrition (Table 3). Maximum number of grains per cob (279.72) were recorded in hybrid P-33H25 with silicon application under normal water supply (100 % FC) while the minimum (184.39) was in hybrid FH-810 at 60 % field capacity without silicon application (Table 4). There was an increase of 36 and 31 grains because of silicon application under abridged moisture supply (60 % FC) in hybrid P-33H25 and FH-810, respectively. Drought stress severely reduced the 100-grain weight i.e g and g of maize hybrids P-33H25 and FH-810, respectively (Table 4). application significantly improved the 100-grain weight of both maize genotypes under well watered (100 % FC) and drought stress conditions (60 % FC). Overall maximum (22.86 g) 100-grain weight was recorded for hybrid P-33H25 under the well watered condition (100 % FC) with silicon application while the minimum (16.23 g) was obtained in hybrid FH-810 under drought (60 % FC) without application of silicon (Table 4). Maximum biological yield ( g) was observed in well watered silicon mediated plants of hybrid P-33H25 while it was lower (83.03 g) in drought stressed plants of hybrid FH-810 that were grown without silicon application. Application of silicon increased biological yield by g and 7.72 g in maize hybrids P-33H25 and FH- 810, respectively under optimal water supply (100 % FC). With silicon nutrition there was an increase of g and g in biological yield for hybrids P-33H25 and FH- 810, respectively under abridged moisture supply (Table 4). Grain yield per plant of maize hybrids FH-810 and P-33H25 was reduced by % and %, respectively because of the water deficit (Table 4). It is obvious from the Table that maximum grain yield (63.95 g) was produced by hybrid P-33H25 where silicon was used under well watered conditions (100 % FC) while the minimum (29.95 g) was attained by hybrid FH-810 without silicon application under the moisture deficit situation (60 % FC). Hybrid P-33H25 had an improvement of % in grain yield with added silicon under water stress while there was a % increase for hybrid FH-810 under the same water regime with silicon application. 3.2 Gas Exchange Characteristics The water deficit significantly reduced the photosynthetic rate of both maize hybrids (Table 5). However, silicon application significantly improved the photosynthetic rate of both maize genotypes under well watered and drought stress conditions at both stages i.e. vegetative (45 DAS) or reproductive (70 DAS). Maximum photosynthetic rate was recorded in both maize hybrids where plants were fertilized with silicon under well watered conditions while was least where silicon was not applied under the water deficit situation (Table 5). The data (Table 5) reveal that drought stress (60 % FC) significantly decreased the transpiration rate as compared to control conditions (100 % FC) in both hybrids P-33H25 (drought tolerant) and FH-810 (drought sensitive) at vegetative (45 DAS) or reproductive stages (70 DAS). Nonetheless, exogenous application of silicon also

7 Table 5 Influence of silicon application on photosynthetic rate (μmol/m 2 /s) and transpiration rate (mmol/m 2 /s) of maize hybrids under well watered and moisture deficit condition Hybrids Drought PR at 45 DAS PR at 70 DAS TR at 45 DAS TR at 70 DAS P-33H % FC 0 mg/kg 16.26b 11.48bc 6.19b 4.48b 100 mg/kg 20.02a 14.28a 6.06b 4.22b 60 % FC 0 mg/kg 9.41d 6.58e 4.46d 2.65c 100 mg/kg 12.08c 8.08d 3.79e 1.99d FH % FC 0 mg/kg 15.63b 10.60c 6.99a 5.16a 100 mg/kg 17.35b 12.25b 6.01b 4.19b 60 % FC 0 mg/kg 6.23e 4.31f 5.06c 3.12c 100 mg/kg 10.79cd 7.57de 4.61cd 2.75c LSD value Values sharing the same letter in a column do not differ statistically at P FC = Field capacity, LSD = Least significant difference, PR = photosynthetic rate, TR = transpiration rate, DAS = days after sowing significantly lowered the transpiration rate in both of the hybrids under normal (100 % FC) as well as the water deficit situation (60 % FC) at both stages (vegetative or reproductive). Maximum transpiration rate (6.99 mmol/m 2 /s) was observed in plants of hybrid FH-810 at 100 % field capacity without silicon fertilization at the vegetative stage (Table 5). 4 Discussion It is evident from the current study that the plant height, stem diameter, leaf number, cob length, number of grains per cob, 100 grain weight, grain yield and biological yield and gas exchange attributes of maize hybrids were significantly influenced when grown in the water deficit condition (60 % FC), (Table 3). Changes in morphological parameters, the reduced seedling growth and yield under limited moisture stress might be because of introverted cell division and extension [38] and this response differs distinctly among various crop cultivars [37]. In the present investigation, exogenously applied different concentrations of Si significantly increased the morphological and yield attributes of both maize cultivars (Table 3). induced increase in plant growth under stress [20] may have been due to the significant role of Si in the upgrading of water status of stressed plants [15] due to lowered transpiration rate [21, 22] like wheat [23] andsunflower [24] etc. Likewise, silicon application significantly increased height of rose, maize and wheat under stressful conditions [25 28]. nutrition not only increased plant height but also the stem thickness. Improvement in stem diameter with silicon treatment might be due to improved growth of drought stressed plants [10]. The silicon mediated improvement in growth not only takes places under the normal condition [29], but also under the stress conditions [6]. Drought conditions significantly reduced the number of leaves in plants of maize hybrids. The grains per cob were reduced significantly under the water limited situation in the present study. The decrease in number of grains might be due to delay in silking under water deficit [36]. Our results are in harmony with the findings of [30] who observed a greater number of spikelets per panicle by silicon application in rice. This could be due to the adequate silicon supply improving the photosynthetic activity [31] as observed in the current investigation (Table 5) which enables maize plants to accumulate sufficient photosynthates. This in turn increases dry matter production and these together with efficient translocation results in greater numbers of filled grains with increased test weight and ultimately leads to higher grain and straw yield [23], increase in number of achenes per head of sunflower [24] and increased weight of grains under the moisture deficit condition in the present investigation (Table 4). The silicon based increase in the photosynthetic activities of drought stressed plants might also be linked to the improved efficiency of chlorophyll content and photosynthetic enzymes like ribulose-bisphosphate carboxylase and NADP+ dependent glyceroldehyde-3-phosphate dehydrogenase under an abridged moisture condition [31]. application was found useful to improve grain yield under limited moisture supply (Table 4). Our results are in harmony with [23]. based improvement in grain yield has been observed in several crops i.e. wheat 50 % [14], rice 15 % [12] etc. Results indicated that silicon increases grain yield by absorption and influencing physical traits. The transpiration rate of maize hybrids was significantly lowered in silicon fertilized drought stressed plants as compared to plants that were grown without silicon supply (Table 5). This decrease in transpiration may be due to deposition of Si beneath the cuticle that hinders loss of water from the cuticle [32] or with deposition of silicate crystals

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