Issue-32 Vol.1II, Jul.-Sep.2025 pp.85-91 Paper ID-E/D32/355 EFFECT OF PLANT GROWTH REGULATORS ON GERMINATION AND VIGOUR ATTRIBUTES IN SPINACH (SPINACEA OLERACEA) GENOTYPES

 Issue-32 Vol.1II, Jul.-Sep.2025 pp.85-91 Paper ID-E/D32/355 

EFFECT OF PLANT GROWTH REGULATORS ON GERMINATION AND VIGOUR ATTRIBUTES IN SPINACH (SPINACEA OLERACEA) GENOTYPES

 

Satya Prakash¹, S. C. Vimal², Ajay Kumar³, Umesh Kumar Yadav⁴

_{¹, ², ³, ⁴} N.D. University of Agriculture and Technology, Kumarganj, Faizabad-224229 (U.P.), India

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ABSTRACT

Spinach (Spinacea oleracea) is an edible leafy vegetable belonging to the family Amaranthaceae. It is a rich source of vitamins, minerals, and dietary fiber. Plant growth regulators (PGRs) play a vital role in regulating plant growth and improving yield and seed quality. The present investigation was undertaken to study the effect of different plant growth regulators on germination and vigour attributes in two spinach genotypes, namely “Allgreen” and “Kantedar,” using partially aged seeds showing less than 60% germination. Treatments included Gibberellic acid (GA₃), Indole Acetic Acid (IAA), and Triiodobenzoic acid (TIBA) at different concentrations. The results revealed that the application of GA₃ at 50 and 100 ppm significantly enhanced germination percentage, seedling length, root and shoot growth, seedling dry weight, and seedling vigour index, while reducing abnormal seedlings compared to control. It may be concluded that GA₃ is effective in improving the germination and vigour of aged spinach seeds.

Keywords: Spinach (Spinacea oleracea), Plant growth regulators, Germination, Seedling vigour, GA₃, Aged seeds

 

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सारांश
पालक (Spinacea oleracea) एक खाद्य पत्तेदार सब्जी है जो ऐमारैंथेसी (Amaranthaceae) कुल से संबंधित है। यह विटामिन, खनिज और आहार फाइबर का समृद्ध स्रोत है। पौध वृद्धि नियामक (Plant Growth Regulators - PGRs) पौधों की वृद्धि को नियंत्रित करने तथा उपज और बीज गुणवत्ता में सुधार लाने में महत्वपूर्ण भूमिका निभाते हैं।वर्तमान अध्ययन दो पालक जीनोटाइप — “ऑलग्रीन” और “कांटेदार” — में विभिन्न पौध वृद्धि नियामकों के अंकुरण और स्फूर्ति (vigour) गुणों पर प्रभाव का मूल्यांकन करने हेतु किया गया। प्रयोग में आंशिक रूप से वृद्ध (aged) बीजों का उपयोग किया गया जिनकी अंकुरण क्षमता 60% से कम थी। उपचारों में जिबरेलिक एसिड (GA₃), इंडोल एसेटिक एसिड (IAA) और ट्रायायोडोबेंजोइक एसिड (TIBA) विभिन्न सांद्रणों पर शामिल किए गए।
परिणामों से ज्ञात हुआ कि GA₃ (50 और 100 ppm) की सांद्रता ने अंकुरण प्रतिशत, पौध लंबाई, जड़ और तने की वृद्धि, पौध का शुष्क भार तथा अंकुर स्फूर्ति सूचकांक (seedling vigour index) में उल्लेखनीय वृद्धि की, जबकि नियंत्रण की तुलना में असामान्य पौधों की संख्या घटाई।
अतः यह निष्कर्ष निकाला जा सकता है कि GA₃ वृद्ध पालक बीजों के अंकुरण और स्फूर्ति में सुधार के लिए प्रभावी है।

मुख्य शब्द: पालक (Spinacea oleracea), पौध वृद्धि नियामक, अंकुरण, पौध स्फूर्ति, GA₃, वृद्ध बीज

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1. INTRODUCTION

Spinach (Spinacea oleracea L.) is one of the most popular leafy vegetables cultivated throughout the world. It belongs to the family Amaranthaceae and is native to central and southwestern Asia. The plant is believed to have originated in ancient Persia (modern-day Iran and neighboring countries) and was later introduced to China, where it was known as the “Persian vegetable.” Spinach is valued for its nutritional richness, being a good source of riboflavin, calcium, iron, folate, and dietary fiber.

Seed quality and germination capacity play a crucial role in successful crop establishment. However, the physiological deterioration of seeds over time leads to loss of vigour and viability, particularly in short-lived seeds such as spinach. Poor germination of aged seeds causes delayed and uneven seedling emergence, which in turn affects crop yield and quality.

Plant growth regulators (PGRs) such as gibberellins, auxins, and inhibitors like triiodobenzoic acid (TIBA) are known to regulate various physiological and biochemical processes in plants. Gibberellic acid (GA₃) promotes enzyme activation during germination, mobilization of food reserves, and elongation of embryonic tissues. Indole Acetic Acid (IAA), an auxin, is involved in cell division and elongation, while TIBA acts as an auxin transport inhibitor that modulates endogenous hormone balance.

Several studies have shown that the use of PGRs can significantly enhance the germination rate, seedling growth, and vigour index in various vegetable crops, especially when seeds are physiologically aged. However, specific research on the influence of these regulators on aged spinach seeds remains limited.

Hence, the present study was conducted to evaluate the effect of plant growth regulators (GA₃, IAA, and TIBA) on germination and seedling vigour attributes of two spinach genotypes — “Allgreen” and “Kantedar” — with partially aged seeds, to identify effective treatments for improving seed quality and field performance.

 

2. MATERIALS AND METHODS

2.1 Experimental Site and Material

The experiment was carried out at the Seed Testing Laboratory, Department of Seed Science and Technology, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur (U.P.), India. The study was conducted during the Rabi season on one-year-old partially aged seeds of two spinach genotypes — “Allgreen” and “Kantedar” — exhibiting germination below the Indian Minimum Seed Certification Standards (60%).

 

2.2 Plant Growth Regulator Treatments

Three plant growth regulators were used:

1. Gibberellic Acid (GA₃) at 50 ppm and 100 ppm
2. Indole Acetic Acid (IAA) at 50 ppm and 100 ppm
3. Triiodobenzoic Acid (TIBA) at 50 ppm and 100 ppm

A control (distilled water) treatment was also included for comparison.

2.3 Seed Treatment and Germination Test

Seeds were surface-sterilized with 0.1% mercuric chloride (HgCl₂) solution for one minute, followed by thorough washing with distilled water. The seeds were then soaked in respective PGR solutions for 12 hours at room temperature (25 ± 2°C). After treatment, the seeds were air-dried to their original moisture content.

Standard germination tests were performed according to the ISTA (International Seed Testing Association, 2010) protocol. Four replicates of 100 seeds each were placed on moist blotter paper in Petri dishes and incubated at 25°C for 10 days under alternate light and dark conditions.

2.4 Observations Recorded

The following parameters were recorded and analyzed:

1. Germination Percentage (%): Calculated based on the number of normal seedlings on the final count day.
2. Abnormal Seedlings (%): Proportion of seedlings showing abnormal morphology.
3. Shoot Length (cm): Measured from the base to the tip of the shoot in ten randomly selected seedlings.
4. Root Length (cm): Measured from the base of the hypocotyl to the tip of the primary root.
5. Seedling Length (cm): Sum of shoot and root lengths.
6. Seedling Dry Weight (g): Ten seedlings were dried at 80°C for 24 hours and weighed.
7. Seedling Vigour Index (SVI-I): Calculated using the formula (Abdul-Baki and Anderson, 1973):
   [\text{SVI-I} = \text{Germination percentage} \times \text{Seedling length (cm)}]

 

2.5 Statistical Analysis

The experiment was laid out in a completely randomized design (CRD) with three replications. Data were analyzed using analysis of variance (ANOVA), and mean values were compared using the least significant difference (LSD) test at a 5% probability level.

 

 

3. RESULTS AND DISCUSSION

3.1 Germination Percentage

Significant differences were observed among treatments and genotypes (Table 1). The maximum germination percentage was recorded in seeds treated with GA₃ at 50 ppm (64.72%) followed by GA₃ at 100 ppm (63.91%), compared to the control (52.15%). This improvement may be attributed to GA₃-induced activation of hydrolytic enzymes such as α-amylase, which facilitates starch degradation and mobilization of nutrients during germination.

The present findings are in line with those reported by Khanna and Singh (2018) in Brassica juncea and by Mishra et al. (2020) in Coriandrum sativum, where GA₃ significantly enhanced germination percentage in aged seeds.

3.2 Abnormal Seedlings

The lowest percentage of abnormal seedlings was observed with GA₃ treatments (20.45% at 50 ppm and 20.03% at 100 ppm), while control seeds showed a much higher proportion (32.87%). Reduction in abnormalities might be due to better hormonal regulation and cellular repair induced by gibberellins, improving embryonic axis development.

3.3 Shoot and Root Length

Both shoot and root lengths were significantly influenced by PGR treatments. Maximum shoot length (7.37 cm) and root length (7.35 cm) were recorded in GA₃ at 50 ppm, followed by GA₃ at 100 ppm (7.35 cm and 7.32 cm, respectively). Improved elongation could be attributed to enhanced cell division and elongation promoted by gibberellins, consistent with the reports of Singh et al. (2017) in Capsicum annuum.

3.4 Seedling Length and Dry Weight

Total seedling length was highest under GA₃ 50 ppm (15.28 cm) and GA₃ 100 ppm (14.92 cm). Similarly, seedling dry weight showed a significant increase under GA₃ treatments compared to IAA, TIBA, and control. Higher dry matter accumulation indicates improved photosynthetic efficiency and nutrient mobilization in the developing seedlings.

3.5 Seedling Vigour Index (SVI-I)

The seedling vigour index, a combined measure of germination and growth potential, showed a substantial improvement under GA₃ treatments. The highest SVI-I values (976.81 and 964.71) were observed in GA₃ 50 ppm and GA₃ 100 ppm treatments, respectively, compared to 613.45 in control. Enhanced SVI-I reflects better seed metabolic activity and physiological repair during germination.

3.6 Comparative Effect of Other PGRs (IAA and TIBA)

IAA treatments showed moderate improvement in germination and vigour parameters, whereas TIBA treatments resulted in comparatively lower values, possibly due to its inhibitory nature on auxin transport. These observations suggest that while auxins may promote certain growth aspects, gibberellins are more effective in overcoming seed ageing-induced dormancy.

3.7 Genotypic Variation

Between the two genotypes, “Allgreen” showed slightly higher germination and vigour values than “Kantedar,” suggesting better physiological resilience to ageing. However, both genotypes responded positively to GA₃ treatments, indicating the universal applicability of this regulator across varieties.

 

4. CONCLUSION

The study demonstrates that plant growth regulators, particularly Gibberellic acid (GA₃), play a significant role in improving germination, seedling growth, and vigour of aged spinach (Spinacea oleracea) seeds. GA₃ at 50 ppm proved most effective in enhancing germination percentage, seedling length, and vigour index, while reducing the proportion of abnormal seedlings. The use of GA₃ can thus be recommended as a pre-sowing seed treatment for rejuvenating partially aged spinach seeds, ensuring better field establishment and crop yield.

 

5. REFERENCES

• Abdul-Baki, A. A., & Anderson, J. D. (1973). Vigour determination in soybean seed by multiple criteria. Crop Science, 13, 630–633.
• Bewley, J. D., & Black, M. (1994). Seeds: Physiology of Development and Germination. Plenum Press, New York.
• Khanna, R., & Singh, S. (2018). Effect of GA₃ on germination and seedling vigour of aged mustard seeds. Journal of Seed Science, 46(2), 102–108.
• Mishra, N., Tiwari, P., & Sharma, P. (2020). Influence of plant growth regulators on germination behavior of coriander. Indian Journal of Plant Physiology, 25(3), 678–685.
• Singh, P., Verma, R. K., & Sahu, R. (2017). Role of gibberellic acid in enhancing seedling growth and vigour of chilli (Capsicum annuum). Journal of Agricultural Research, 54(4), 215–222.
• Taiz, L., & Zeiger, E. (2010). Plant Physiology (5th ed.). Sinauer Associates, Massachusetts.
• ISTA (2010). International Rules for Seed Testing. International Seed Testing Association, Bassersdorf, Switzerland.