Volume 4 Issue 2 2025 – Page 2 – Journal of Plant Biota

Optimized Water-Agar Assay for Tomato Seed Vigor Enables High-Fidelity Plant Growth Regulator Screening

Mahesh R. Ghule¹
Monika C. Narayankar²
Priti B. Panchal²
Kirti T. Kamthe³
Adwait K. Kamthe¹
Sunita S. Sakure²

Introduction Tomato (Solanum lycopersicum L.), a member of the Solanaceae family, is one of the world’s most important vegetable crops, valued for its economic, nutritional, and scientific significance. Originating in western South America, tomato cultivation has expanded globally and today ranks as the second most produced vegetable after potato by volume [1, 2, 3]. In 2022, global tomato production reached ~186.8 million metric tons across 5 million hectares, underpinning a multi-billion-dollar industry that spans fresh produce and processed products such as sauces and pastes [4]. Nutritionally, tomatoes are low in calories but rich in vitamins A, C, and K, minerals, dietary fiber, and phytochemicals, most notably lycopene. Lycopene is a potent antioxidant linked to reduced risks of cardiovascular diseases and several cancers [5, 6, 7, 8]. This combination of agricultural, economic, nutritional, and health value has also made tomato a model organism for studies in genetics, physiology, and biotechnology [1, 9]. Successful and uniform crop establishment begins with seed quality. While viability defines the inherent ability of a seed to germinate, vigor is a superior predictor of performance under diverse and stressful field conditions [10, 11]. Seed vigor is characterized by rapid, uniform germination and robust seedling development. Standard germination tests (SGTs), such as those prescribed by ISTA and AOSA, measure maximum germination potential under optimal conditions [12]. However, these conditions rarely reflect field realities, and SGTs often overestimate emergence capacity. Even weak or damaged seeds may germinate in the laboratory yet fail in the field [10, 13]. To bridge this gap, seed vigor testing has become an essential component of seed quality assessment [14, 15]. For tomato, high vigor is critical for field establishment and yield uniformity [16]. The rolled paper towel (PT) method is widely used for SGTs due to its low cost and simplicity. However, it presents limitations for vigor testing and sensitive applications such as plant growth regulator (PGR) screening. Moisture regulation in PT is inconsistent: excessive wetness can create anaerobic conditions leading to seed rot, while drying can arrest germination. In addition, seedling radicles often entangle within the paper matrix, causing damage during measurement and increasing variability [17, 18]. The opaque, rolled setup further prevents real-time observation of germination. Studies have shown that agar-based substrates generate more uniform seedlings than paper or sand [19]. Water-agar (WA), a sterile, semi-solid, nutrient-free medium, provides several advantages. It offers stable and uniform moisture, prevents substrate entanglement, and allows continuous, non-invasive observation of germination. However, agar concentration critically influences water potential and gel firmness. Higher agar concentrations reduce water availability by lowering matric potential, imposing resistance to root penetration and creating physiological drought [20, 21]. Conversely, excessively low concentrations may cause free water release or hypoxia [22]. Hydrothermal modeling further confirms that water × temperature interactions strongly regulate germination dynamics [23, 24]. Thus, optimizing agar concentration is essential for accurate assessment of seed vigor. This study aimed to (1) optimize agar concentration for tomato seed germination and vigor, and (2) compare the optimized WA method with the PT method for high-fidelity screening of tomato seed responses to two PGRs indole-3-butyric acid (IBA) and gibberellic acid (GA₃). Materials and Methods Plant Material and Sterilization Seeds of tomato (S. lycopersicum cv. Seminis Abhilash, Bayer Crop Science, India) were used. Seeds were stored at 4 °C in airtight containers. For sterilization, seeds were immersed in 70% ethanol for 1 min, followed by 1.5% sodium hypochlorite with Tween-20 for 10 min, and rinsed five times with sterile distilled water. Experiment 1: Optimization of WA Concentration A completely randomized design (CRD) tested six substrates: sterile distilled water (0% agar) and agar concentrations of 0.13, 0.25, 0.50, 1.0, and 2.0% (w/v). Agar (HiMedia, India) was autoclaved (121 °C, 20 min) and poured into sterile 6-well plates (10 mL/well). After solidification, 10 sterilized seeds were placed per well (100 seeds/treatment). For 0% agar, 10 mL sterile water was used. Plates were sealed with Parafilm, incubated at 25 ± 2 °C under a 16 h dark/8 h light regime (ISTA protocol) [12]. Experiment 2: Comparative Analysis of WA vs. PT for PGR Screening A factorial CRD design compared WA (0.5% agar, from Experiment 1) with PT across six concentrations each of IBA (0, 10, 25, 50, 100, 200 mg/L) and GA₃ (0, 50, 100, 200, 400, 800 mg/L) [25, 26, 27]. WA method: PGRs were filter-sterilized and incorporated into molten 0.5% agar. Ten mL medium was dispensed per well, with 10 seeds/well. PT method: Two sterile germination papers were moistened with PGR solution, seeds placed, rolled, and enclosed in polyethylene bags. Each treatment had 10 replicates (100 seeds). Incubation conditions were as in Experiment 1. Data Collection In Experiment 1, germination was recorded daily for 14 days. A seed was considered germinated when radicle length ≥2 mm [12]. Final germination %, mean germination time (MGT), shoot/root length, seedling length, seedling vigor index (SVI = germination % × mean seedling length), fresh weight, dry weight, and biomass gain were recorded. In Experiment 2, germination was assessed on day 7. Shoot and root length, SVI, and qualitative differences between WA and PT seedlings were recorded. Coefficients of variation (CV) for shoot/root length were calculated. Statistical Analysis Data were analyzed by one-way ANOVA (Experiment 1) and two-way ANOVA (Experiment 2) with Tukey’s HSD test (P ≤ 0.05). Data normality and homogeneity were verified; no transformation was required. Analyses were performed using R v4.1.2. Results and Discussion Water-Agar Concentration Optimization for Seed Vigor WA substrates consistently outperformed the water-only control, which was limited by hypoxic stress. The 0.5% WA medium proved optimal, achieving 95% germination and the highest vigor index, consistent with earlier reports on tomato seed vigor under controlled water potential [11,24,29,31]. In the water-only treatment (0% WA), germination was significantly lower and slower than in any agar-containing medium (Table 1). After 14 days, the control reached only ~62% germination, compared with 82–95% across WA treatments. Seeds germinated in water required considerably more time (MGT ≈ 6.3 days) and produced weak seedlings averaging ~23 mm in total length, which … Read more

An Assessment of Rural Households Perception of Climate Change in Taraba State, Nigeria

Oruonye, E.D.¹
Ojeh Vincent Nduka¹
Linda Sylvanus Bako¹
Ezra, A.²

Introduction Climate change represents one of the most pressing global challenges of the 21st century, affecting the environment, economies, and societies in multifaceted ways. Its impacts are disproportionately felt in developing regions, particularly in sub-Saharan Africa, where livelihoods are largely dependent on climate-sensitive sectors such as agriculture and forestry [1]. Nigeria, as Africa’s most populous nation, faces significant climate-related risks including rising temperatures, irregular rainfall patterns, prolonged droughts, and increasing incidences of flooding. These changes threaten food security, water availability, and health, particularly in rural areas where adaptive capacity is generally low [2]. Taraba State, located in the northeastern region of Nigeria, exhibits a diverse agro-ecological landscape comprising the Sudan Savannah, Northern Guinea Savannah, Southern Guinea Savannah, and Montane zones. These zones are home to numerous rural communities whose livelihoods are intricately tied to natural systems. Consequently, any alteration in the climate system has profound implications for their socio-economic well-being. Despite the evident impacts of climate change, understanding how rural populations perceive these changes remains limited. This knowledge gap is critical because perception influences response and adaptation strategies at the community level [3]. Perceptions of climate change among rural populations are shaped by various factors including ecological location, cultural beliefs, religious orientation, and direct environmental experiences. In some rural Nigerian contexts, changes in climate are not solely attributed to scientific or physical causes but are often linked to spiritual or moral explanations such as divine punishment for societal wrongdoing [4]. Understanding these perceptions is essential for designing context-specific climate change communication and adaptation strategies that are both culturally sensitive and scientifically sound. Although several studies have examined the physical manifestations of climate change in Nigeria, few have focused on local perception, especially in ecologically diverse states such as Taraba. Assessing rural households’ perception is not only important for enhancing scientific knowledge but also for informing policy and grassroots action plans aimed at building resilience to climate shocks. Perception studies can help identify knowledge gaps, promote behavior change, and improve the targeting of adaptation interventions [5]. This study, therefore, seeks to assess rural households’ perception of climate change in Taraba State, Nigeria. It aims to explore how rural residents interpret the causes of climate change, the extent to which their perceptions differ across agro-ecological zones, and the socio-cultural and environmental factors influencing these perceptions. By doing so, the study contributes to a deeper understanding of local environmental cognition and supports the development of tailored climate adaptation policies. Statement of the Research Problem Climate change continues to pose an existential threat to global development, with its impacts disproportionately affecting vulnerable populations, especially in rural and ecologically diverse regions of sub-Saharan Africa. In Nigeria, where over 70% of the population depends on climate-sensitive activities such as agriculture and natural resource extraction, the rural populace remains at the frontline of these environmental challenges [2]. Taraba State, characterized by complex agro-ecological zones and a largely rural demographic, is particularly vulnerable due to its dependence on rain-fed agriculture, extensive deforestation, and low adaptive capacity. Despite increasing scientific evidence and global awareness of climate change, there remains a significant gap in understanding how rural communities in Nigeria, particularly in Taraba State, perceive the phenomenon. Perception is a key determinant of climate response; it shapes risk appraisal, decision-making, and local adaptation strategies [3, 5]. However, rural perceptions are often influenced not only by direct environmental experiences but also by cultural, religious, and social interpretations. For instance, earlier findings suggest that some rural households in Taraba State attribute climate change to spiritual causes such as divine punishment rather than scientific explanations such as greenhouse gas emissions or land use change [4, 6]. This divergence in perception may result in limited acceptance or misalignment with formal climate change communication and mitigation initiatives. Moreover, variation in perception across ecological zones may further complicate policy formulation and implementation. Without a clear understanding of how rural households interpret climate change and its causes, efforts to promote adaptation and resilience-building at the community level risk being ineffective or culturally inappropriate [1]. While existing studies in Nigeria have predominantly focused on the biophysical impacts of climate change or macro-level vulnerability assessments, little empirical research has been conducted to capture the nuanced, localized perceptions of rural households in Taraba State. There is, therefore, a compelling need to examine these perceptions systematically, identify their socio-cultural and ecological drivers, and assess the extent to which they align with scientific understanding. This study addresses this critical gap by assessing rural households’ perception of climate change across the four agro-ecological zones of Taraba State. It provides evidence-based insights necessary for designing culturally sensitive and geographically targeted climate adaptation policies and education programs. Description of the Study Area Taraba State, located in the northeastern region of Nigeria, lies between latitudes 6°30′N and 9°36′N and longitudes 9°10′E and 11°50′E (Fig. 1). It shares international boundaries with the Republic of Cameroon to the east and national boundaries with Bauchi, Gombe, Adamawa, Benue, Nassarawa, and Plateau States. With a land area of approximately 54,473 square kilometers, it ranks among the largest states in Nigeria by landmass [7]. Taraba State exhibits diverse topographical and ecological characteristics shaped by its position on the windward side of the Cameroon Highlands. The state’s landscape ranges from low-lying plains in the north to high-altitude mountainous terrains in the southeast, notably in the Mambilla Plateau region which rises to over 1,800 meters above sea level. This ecological variability contributes to its classification into four major agro-ecological zones: the Sudan Savannah, Northern Guinea Savannah, Southern Guinea Savannah, and the Montane zone. These ecological zones influence not only the state’s biodiversity and agricultural productivity but also how communities experience and respond to climate-related changes. For instance, the Montane zone experiences cooler temperatures and higher rainfall, while the Sudan Savannah in the north is drier and more prone to desertification and drought. The state experiences a tropical climate, with two distinct seasons: the rainy season (April to October) and the dry season (November to March). Annual rainfall varies between 800 mm in … Read more

Response of wheat plants (Tritium astrium L.) to NPK Nano fertilizer under saline soil conditions in Nineveh Governorate

Hind Awad Sabbar
Khalid Ekhlayef N. Alhadidi
Rana Saadallah Aziz

Introduction Wheat is an essential source for the production of bread in many countries of the world. It is also considered an important source of proteins, calories, fats, vitamins, and mineral salts [11]. Wheat protein contains approximately 35% gluten, which helps in producing good types of bread compared to the resulting of bread. Among other grain crops, the wheat crop is also used in the production of some medicines, while wheat waste is used as animal feed. Because of the importance of the wheat crop and its nutritional role, it is called the king of grains , Nano fertilizer technology is one of the recent discoveries that provides solutions to many problems in the agricultural field [15]. Nano refers to a unit of measurement that denotes one billionth (10-9) of a meter. Nanotechnology means the technology of extremely small materials. Or microscopic technology. Scientists and engineers deal with matter at this scale at the level of atoms and Nanoparticles [25]. The Nano unit is used to measure microscopic particles, atoms, and diameter dimensions [2]. The difference in the behavior of Nanomaterials is due to two basic factors: The first factor is the increase in area. The surface area of the material, which will lead to an increase in the specific surface area, so the interaction of the material increases, and then its chemical activity becomes higher [8]. The second factor is the quantitative effects in these Nanomaterials, and because of their small dimensions, they are not subject to the laws of classical physics, but they are subject to the laws of quantum physics, so they affect… in their properties, which is reflected in the optical, electrical, magnetic and mechanical behavior of materials [14]. Salinization is the process of gathering or accumulating dissolved salts to a degree exceeding their natural rates in the soil. The cause of salinization may be natural or due to conditions resulting from poor management processes [6]. Saline soils are characterized by chemical, physical, biological, and morphological characteristics different from non-saline soils. They are also characterized by a predominance of Certain types of cations and anions [19]. The area of land affected by salts reached (340 million hectares) at the global level, while the area of sodic lands reached (560 million hectares). Salinity, in addition to the osmotic effect, is an ionic effect that is often associated with high levels of sodium to potassium (K+ /Na+) and sodium to calcium ( Ca++ /Na+), magnesium to calcium (Ca++ /Mg++), and chloride to nitrate (NO3 / Cl-), which means the accumulation of both sodium and chloride in the plant tissue in addition to the soil, which affect water stress and cause the absorption of the main nutrients to be affected. Interactions, ionic competition, or influence the integrity of the cell membrane [27]. Sodium competes with potassium, calcium, and magnesium, in addition to manganese, and reduces the amount available to the plant or replaces the calcium ion in the binding sites in the cytoplasmic membranes, which negatively affects their selective property, while chloride restricts the absorption of nitrates and phosphates in addition to sulfates [20]. Materials and Methods Collecting soil samples and preparing them for study: Three sites were chosen from Nineveh Governorate within the (Tel Abta) area due to the importance of these sites from an agricultural standpoint as they are grown with grain crops and irrigated supple mentally depending on the difference (rainfall range, vegetation cover, variation in salt distribution). Excited samples were taken at a depth of (0 – 30) cm. On 10/5/2023 from the study sites, Table (3), samples were taken to prepare them for cultivation for analyzes and laboratory studies according to the methods mentioned in [22]. Chemical and physical analyses The soil extract (1:1) was used to estimate dissolved ions. The electrical conductivity (EC) and the degree of soil reaction (pH) were measured using the WTW Multi 4001 device [20]. Calcium and magnesium were calibrated with (0.01N) of ferricin (EDTA di -Na) [20], I use a Shewood model 410 flame photometer to measure both sodium and potassium in the soil extract after adjusting the device with standard solutions and based on [26], carbonates and bicarbonates by calibration with (0.01N). Of sulfuric acid and using the phenolphthalein index to estimate carbonates and the methyl orange index in the case of bicarbonate. Chlorides were estimated by titration with (0.01N) of silver nitrate (AgNO3 [26]. Sulfates were calculated from the difference between the sum of dissolved positive ion equivalents and dissolved negative ion equivalents [22], organic matter was estimated by the wet oxidation method using potassium dichromate (K2Cr2O7) [20], total carbonates (lime) were estimated by titration method with hydrochloric acid at a concentration of (1M) phenolnaphthalene index [10], it was Gypsum was estimated by the acetone precipitation method according to the method used by [18]. The hydrometer method was used to estimate soil separations of clay, silt, and sand, according to what was mentioned by [13]. The bulk density was estimated by the paraffin wax method [17]. Implementation of the experiment Plastic pots with a diameter of (25 cm) and a depth of (35 cm) were filled with (7) kg of air-dry soil and sifted through a sieve with a diameter of (4 mm). (10 seeds) of wheat variety (durum desf) were planted in each pot at a depth of (1 cm) from the soil surface, taking into account the selection of healthy seeds of similar sizes. After (10) days of planting, the plants thinned to only three plants per pot. As for the irrigation process, the experimental plants will be placed below 75% of the field capacity of the soil, using water (the Tigris River) throughout the experiment period, and the irrigation process will be conducted using the gravimetric method by weighing each pot and then adding water to the pot for the purpose of obtaining the wet weight. Experiment design: The experiment will be implemented according to a completely randomized design with three replications as a factorial experiment with three factors: … Read more