Seasonal variation in morphological characteristics of Brahmi (Bacopa monnieri) germplasm accessions in coastal regions of Andhra Pradesh

Introduction

Exploring the medicinal properties of plants has been a cornerstone of human healthcare for centuries. From ancient civilizations to the present day, humans relied on medicinal plants for their well-being. Among them, Brahmi (Bacopa monnieri) ranks second among the most indispensable Indian medicinal plants (Gupta et al., 2017) [9] which belongs to Scrophulariaceae family. It is a creeping, succulent perennial herb with branches that grow in marshy and wet areas (Kumar, 2017) [12] . Brahmi is often recognized as Medhya Rasayana, a traditional Indian medication having beneficial effects in alleviating anxiety and necrosis as well as enhancing intelligence and memory function (Srivastava et al., 2017) [17] . It is a primary component in various ayurvedic formulations including Brahmeegritham, Brahmi oil, Saraswatharishtam etc. (Beena et al., 2018) [2] . Among various chemicals isolated from Brahmi, the active fractions includes Bacoside A and Bacoside B (Mathur et al., 2016) [13] , which is used to treat various disorders like Alzheimer's, Parkinson's, cancer, ulcer etc. (Sharma et al., 2021) [16] . The demand for this crop has increased annually due to its potential use in the pharmaceutical industry and Ayurvedic medical system. It is essential to record the diversity of a crop, which encompasses superior traits and active components across different seasons, in order to facilitate its profitable cultivation. Several studies have demonstrated the significant impact of different seasons on vegetative growth. Hence this study was conducted to access morphological characterization among different accessions across seasons.

Materials and Methods

The present investigation was carried out during kharif (July-September), Rabi (October-February) and summer Plant height is a significant character, since whole herb is used therapeutically (Devendra et al., 2018) [5] . Favourable conditions in temperature, humidity and rainfall increased cell division and elongation contributing to enhanced plant height ( [18] and Jessika et al. (2018) [11] in Ocimum basilicum. Plant height showed a significant positive correlation with number of leaves (Raja et al., 2020) [14] . These findings are in line with the results reported by Sakhubai et al. (2020) in Plectranthus forskholii.

Number of nodes

The maximum number of nodes were noticed in kharif season followed by Rabi and summer. In kharif, Rabi and summer season, maximum number of nodes was observed in accession APBmDuring rainy season, plants show higher stem growth due to increased water availability, improved nutrient uptake, enhanced photosynthesis and favourable soil and temperature conditions. In winter, lower temperatures slow down plant metabolism and hinder growth. During the summer season, a deficit of water adversely impacted the cellular growth in the stem (Bistgani et al., 2024), leading to a decrease in leaf production. Consequently, there was a reduction in the transportation of carbohydrates to the stem, contributing to diminished growth (Adachi et al., 2000) [1] .

Number of stolons

From the results (Table 1) number of stolons were recorded significantly highest during kharif season and lowest in summer season. Maximum number of stolons were observed and recorded in APBm-1 (17.67) whereas minimum in APBm-25 (12.17) in kharif season. During Rabi, maximum number of stolons in APBm-21 (12.67) and minimum in APBm-24 (6.50).

In summer, more number of stolons were obtained in APBm-3 and APBm-5 (9.50) and less in APBm-13 (6.82).

In kharif season, enhanced branching facilitated more number of stolons (Gibson and Hollowell, 1966) [7] . In the summer, the extended periods of daylight triggered a decrease in stolon production as reported by Eagles and Othman in 1986.

Number of branches

The data obtained by recording the number of branches were more in kharif season compared to Rabi and summer. During kharif maximum number of branches was noticed in APBm-14 (25.16) and minimum in (18.00). In Rabi season, APBm-14 (21.50) observed maximum and minimum in APBm-26 (11.50).

In summer season, the maximum number of branches was obtained during APBm-5 (20.17) and least in APBm-26 (14.00). Gothandan et al. (2021) [8] reported that there is a positive correlation between plant height and number of branches.

Conclusion

From this study it is concluded that there is a significant variations are shown in the morphological traits i.e., plant height, number of leaves, number of branches, number of stolons, stem length and number of nodes are influenced by seasons. Kharif season showed more plant morphological characters compared to other seasons. APBm-10, APBm-1 and APBm-16 observed maximum plant height in kharif, Rabi and summer respectively. APBm-14 had the highest number of leaves, stem length and branches in kharif and Rabi. APBm-5 had the maximum number of leaves, branches and stem length in summer. APBm-10 consistently had the maximum number of nodes in all seasons. For the number of stolons, APBm-1, APBm-21, and APBm-3 had the highest values in kharif, Rabi and summer respectively.

Future scope

These accessions can be utilised for studying optimal harvesting month to maximize fresh and dry herbage yield and bacoside content

References

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