Effects of Salinity on Seed Germination and Physiological Traits of Tall Fescue (Festuca arundinacea Schreb.)

10.30486/roce.2018.545282

Abstract

Abstract
 
Water salinity is one of the most progressive environmental factors limiting the growth and productivity of plants. The objective of this study was to evaluate the effects of salt stress on seed germination and some quantitative trait of tall fescue. For this purpose, a laboratory experiment was conducted at seed laboratory, Islamic Azad University, Isfahan Branch. The traits were radicle and plumule length, fresh and dry weight of radicle and plumule and some properties of seed germination such as germination percent, mean germination time, germination speed, and germination energy and vigor index. Seeds were arranged in petri dishes with 4 replications in completely randomized design with six levels of water salinity including 0, 4, 5, 6, 7 and 8 dSm−1. The results indicated that salinity stress had significant effect on seed germination and physiological characteristics. The results indicated that salinity of irrigation water significantly reduced all studied properties exception of germination time. The values of these properties were continuously decreased with increasing salinity levels. However, time of germination in salinity levels of 4−7 dSm−1 was significantly higher than that distilled water. Seed vigor index was more affecting salinity stress than germination percent.
 
Keywords:Salinity, Germination, Turfgrass, Radicle, Plumule, Seed
 

Keywords


Original Research

 

                 Research on Crop Ecophysiology                                   Vol.13/1, Issue 1 (2018), Pages: 41 - 48

 

 

 

 

 

Effects of Salinity on Seed Germination and Physiological Traits of Tall Fescue (Festuca arundinacea Schreb.)

 

 

Ahmad Gholamzadeh1, Davood Naderi*1 and Ali Soleymani2

1 Department of Horticulture, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran

2 Department of Agronomy and Plant Breeding, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran

 

Corresponding author email: d.naderi@khuisf.ac.ir

Received: 15 December 2017                                           Accepted: 18 January 2018

 

 

Abstract

 

Water salinity is one of the most progressive environmental factors limiting the growth and productivity of plants. The objective of this study was to evaluate the effects of salt stress on seed germination and some quantitative trait of tall fescue. For this purpose, a laboratory experiment was conducted at seed laboratory, Islamic Azad University, Isfahan Branch. The traits were radicle and plumule length, fresh and dry weight of radicle and plumule and some properties of seed germination such as germination percent, mean germination time, germination speed, and germination energy and vigor index. Seeds were arranged in petri dishes with 4 replications in completely randomized design with six levels of water salinity including 0, 4, 5, 6, 7 and 8 dSm−1. The results indicated that salinity stress had significant effect on seed germination and physiological characteristics. The results indicated that salinity of irrigation water significantly reduced all studied properties exception of germination time. The values of these properties were continuously decreased with increasing salinity levels. However, time of germination in salinity levels of 4−7 dSm−1 was significantly higher than that distilled water. Seed vigor index was more affecting salinity stress than germination percent.

 

Keywords:Salinity, Germination, Turfgrass, Radicle, Plumule, Seed

 

Introduction

 

In the arid and semiarid regions, increasing demand for water, has forced to apply non-potable water such as saline water for plant irrigation. Water salinity is one of the most progressive environmental factors limiting the growth and productivity of plants in irrigated areas (Katerjiet al., 2003; Asgari et al., 2012). Iran comprises of about 90 percent of arid or semi-arid (Qadir et al. 2008), and saline soils in the country cover more than 34 million ha (FAO 2000). Water shortage and drought is another crisis which is increasing in the last few decades in central parts of the country. This is one of the major limiting factors of plant growth (Sadeghian and Yavari 2004).

Due to the low rainfall, irrigation of soils is necessary for prosperous plant growth. But, reduction of appropriate water resources is a major factor that can limit agricultural activities. One imperative response to this challenge is the use of anomalistic (saline) sources of water.

Salinity stress due to increased apply of non-potable water sources for irrigation imposes major limitations on plant growth (Yu et al., 2015). Salt strongly affects plant growth, development and productivity (Epstein et al., 1980). The detrimental impacts of salinity on plant growth may be attributed to toxicity of excessive Na, Cl, SO4, CO3, HCO3, and BO3, as well as nutrient imbalance and deficiency (Bowman et al., 2006). Using saline water for cropland irrigation led to soil salinization, reduction in crop yield and degradation of the soil resources, if appropriate management practices are not adapted (Ould Ahmed et al. 2007). Salinity induces osmotic stress by inducing both the accumulation of toxic levels such as Na and Cl and the uptake inhibition of plant essential nutrients (Munns, 2002). Osmotic stress also led to the reduction of water uptake capability by plant roots and therefore reduction of plant growth and productivity (Netondo et al., 2004). Generally, salinity prevents plant growth, with reductions in plant biomass (Rameeh et al., 2004).

Tall fescue (Festuca arundinacea) is a greatly applied cold season turfgrass. In many cases, this turfgrass is grown under fluctuating photosynthetic photon flux densities (Xu et al., 2013). Salinity stress of turfgrass is becoming prevalent because of the increase in using wastewater containing salts for turfgrass irrigation. The need for salt tolerant turfgrass cultivars has considerably increased in recent decades (Marcum, 2006). Plant parameters such as shoot growth, root mass, root length, and turf quality are well suited for examining salinity tolerance in turfgrass species (Alshammary et al., 2004). Under salinity stress, managing turfgrass is becoming more important with the increasing use of recycled water for irrigation (Leskys et al., 1999). Therefore, the objective of this study was to evaluate the effects of salt stress on seed germination and some quantitative trait of turfgrass.

 

Materials and methods

 

In order to the determine the effects of water salinity on seed germination and physiological trait of tall Festuca a laboratory experiment was conducted at seed laboratory, Islamic Azad University, Isfahan Branch in  2015. Seeds of tall Fescue (Festuca arundinacea Schreb.) were submerged in 5% sodium hypochlorite solution for 2 min, followed by three rinses with deionized/distilled water. Also, seeds were disinfected with Benomyl fungicide solution for 2 min, followed by three rinses with deionized/distilled water (references?). Then, 25 seeds were arranged and seeded in each Petri dish (8 cm in diameter) with 4 replications in completely randomized design with six levels of water salinity including 0, 4, 5, 6, 7 and 8 dSm−1 (NaCl). The plants were maintained in a germinator and during growth period (three weeks), humidity (45%) and temperature (25 ◦C) were similar. Several physiological characteristics of turfgrass such as radicle and plumule length, fresh and dry weight of radicle and plumule and some properties of seed germination such as germination percent, mean germination time, germination speed, and vigor index were determined at the end of growth period.

 

Statistical analysis

 

Analysis of variance (ANOVA) was used to assess the effects of salinity on all analyzed plant properties. Means were compared by least significant difference (LSD) test (p<0.05). Statistical procedures were carried out using the software package SAS 9.1 for Windows.

Results

Results showed that salinity levels significantly affected germination (Table 1) and growth properties of Tall Fescue (Table 2). The results indicated that salinity stress had significant effect on seed germination and physiological characteristics. Seed germination rates, plant mass, decreased as salinity levels increased (Table 1 and 2). The results indicated that salinity of irrigation water significantly reduced all studied properties exception of time of germination. The values of these properties were continuously decreased with increasing salinity levels. However, time of germination in salinity levels of 4−7 dSm−1 was significantly higher than that distilled water (Table 1). Vigor index was more affecting salinity stress than germination percent (Table 1). Under salinity levels of 8 dSm−1, seed germination percentage, germination speed, uniformity of germination, and vigour index were reduced approximately 17, 29, 40, and 53% compared to distilled water respectively (Table 1). However, time of germination in salinity levels of 4−7 dSm−1 was significantly higher than that distilled water. Under salinity levels of 8 dSm−1,time of germination was increased about 15% compared to distilled water (Table 1). Means comparison showed that water salinity had significant effect on radicle length (Table 2). Radicle length strongly decreased with increasing salinity levels. Compared with the distilled water, radicle length was 57% lower under salinity levels of 8 dSm−1. Also results indicated that plumule length, fresh weight of radicle, dry weight of radicle, fresh weight of plumule, dry weight of plumule, under salinity levels of 8 dSm−1 were about 19, 16, 35, 19, and 24-times lower than those of distilled water, respectively.

 

Table 1. Germination properties of Tall Fescue affected by water salinity

Salinity

Germination percentage

Germination speed

Uniformity of germination

Time of germination

Vigor index

(dSm−1)

(%)

-

-

day

-

0

81.75 a

0.133a

0.112 a

8.43 b

3.20 a

4

78.17 ab

0.120b

0.111 a

9.81 a

2.61 b

5

76.17 b

0.121b

0.074bc

9.38 a

2.15 c

6

71.83 c

0.111 c

0.079b

9.47 a

1.66 d

7

71.33 cd

0.103cd

0.070c

9.70 a

1.72 d

8

67.67 d

0.095d

0.067c

8.81 b

1.51 d

LSD

3.82

0.008

0.0095

0.57

0.29

In each column, the values followed by at least one common character are not statistically (p<0.05) different, according to the LSD test.

 

Table 2. Growth properties of Tall Fescue affected by water salinity

Salinity

Radicle length

Plumule length

Fresh weight of radicle

Dry weight of radicle

Fresh weight of plumule

Dry weight of plumule

(dSm−1)

(cm)

(cm)

(mg)

(mg)

(mg)

(mg)

0

5.23 a

2.30 a

1.27 a

0.48 a

5.26 a

0.83 a

4

3.98 b

2.42 a

1.15 ab

0.43 b

4.70bc

0.73 b

5

3.26 c

2.15 ab

1.15 ab

0.34 c

4.95b

0.73 b

6

2.41 d

1.96 bc

0.78 c

0.31 c

4.69 cd

0.70 bc

7

2.89 c

1.75 c

1.25 a

0.34 c

4.59 bc

0.67 cd

8

2.24 d

1.87 bc

1.07 b

0.31 c

4.25c

0.63 d

LSD

0.41

0.28

0.17

0.044

0.48

0.056

In each column, the values followed by at least one common character are not statistically (p<0.05) different, according to the LSD test.

 

 

Discussion

 

The present study aims to investigate salt stress effects on seed germination and some quantitative trait of Tall Fescue. The results revealed that water salinity affects morphological, physiological, seed germination. The results indicated that salinity of irrigation water significantly reduced all studied properties. This finding is in according with many studies. Many studies found that the vegetative growth and crop yield decreased with increase in irrigation water salinity (Rameeh et al., 2004; Marcum, 2007; Huang et al., 2009; Wang and Zhang, 2010; Yarami and Sepaskhah, 2015). For example, Zhang et al. (2013) indicated that salinity reduced final and daily germination rate, fresh weight, dry weight, and absolute water content and vegetative growth such as shoot and root dry weight and the longest root length.

In present study, vigor index was more affecting salinity stress than germination percent. However, Zhang et al. (2013) found that daily germination rate, fresh weight and absolute water content, and root dry weight and the longest root length are more sensitive to salinity compared to other properties. Zhang et al. (2011) illustrated that salinity reduced the final and daily germination rate of 12 turfgrasses. High salt contents in the soil may prevent seed germination mainly to the osmotic effect (Alshammary, 2012). Increase in salt concentrations greatly enhances the percentage of abnormal seedlings, due to the salt toxic action on germinating seeds (Lima et al., 2005).

Marcum and Murdoch (1994) also reported that shoot growth was reduced by 50% at the salinity level of 35.9−36.4 dSm−1 NaCl in two fescue varieties which is in agreement with our present study. Also, Uddin et al. (2010) reported that shoot and root growth rate gradually decreased as the salinity increased. Salinity affects many physiological and morphological properties such as seed germination, plant growth, and water and nutrient uptake (Willenborg et al., 2004). Photosynthesis is a main parameter used to monitor plant response to abiotic stress. Salinity stress reduces the ability of plant to uptake water and decrease growth rate, and consequently photosynthesis rate (Jensen et al., 1996). Xu et al. (2013) also demonstrated that the shoot height, root length, shoot and root mass of turfgrass decreased significantly with increasing NaCl concentrations.

Marcum (2008) reported that shoot growth of turfgrass species declined linearly with increased salinity stress. Pompeiano et al. (2014) also found that top plant growth, expressed as cumulative clipping dry weight of warm–season grasses significantly decreased with increasing salinity. Water salinity may lead significant morphological, physiological and biochemical changes in higher plants (Pompeiano et al., 2014). Yu et al. (2015) reported that water salinity stress imposed serious limitations to growth and physiological activities of Bermudagrass. In a greenhouse experiment, Gao et al. (2012) investigated physiological responses of tall fescue leaves to carbonate, chloride, and sulfate and found that NaCl had the lowest EC and highest osmotic potential, and induced less growth reduction and physiological stress compared to Na2CO3, Na2SO4, and CaCl2.This study showed that salinity reduces or delays seed germination, seedling development, and vegetative growth which are similar to the finding in turfgrass species (Marcum, 2007).

 

Conclusions

This work indicated that salinity stress in Tall fescue may be reflected by plant properties such as seed germination, seed growth and plant growth. The results confirmed that salinity stress had significant effect on seed germination and physiological characteristics. Salinity of irrigation water significantly reduced all studied properties (with the exception of time of germination). Vigor index was more affecting salinity stress than germination percent.

 

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