| Abstrakt: |
Background and Objectives: To optimize water usage and cultivate robust seedlings, a comprehensive understanding of the grey mangrove habitat conditions across two vegetative periods and their growth responses in nursery settings is essential. This study aimed to assess the germination rates and growth outcomes of grey mangroves under varying light intensities, irrigation levels, and their combined effects during two distinct 3-month growth phases in a nursery environment. The research sought to elucidate how these factors influence germination percentages and overall performance of grey mangrove seedlings, providing valuable insights for more efficient and sustainable nursery practices. Materials and Methods: Propagules sourced from 30 healthy mother trees during the summer of 2022 were distributed across five groups, each containing three plastic pots, within a coastal nursery utilizing a factorial statistical design. Various irrigation frequencies (twice daily, once daily, every other day, and every second day) and light treatments spanning five levels (0%, 25%, 50%, 75%, and 100%) were administered to the propagules. The study aimed to assess the vegetative responses of seedlings to light and irrigation over two 3-month periods by measuring collar diameter, height, and leaf count (post-bifoliate stage) using digital calipers and a ruler. Growth increments were computed based on changes in collar diameter and height across the two 3-month periods. Germination percentages were documented at the start of growth, while leaf area measurements of 6-month-old seedlings were conducted across all treatments. Statistical analysis using General Linear Models (GLM) at a significance level of 95% was employed to analyze the data, shedding light on the impact of light and irrigation on the growth and development of grey mangrove seedlings in nursery conditions. Results: Based on the findings, the germination percentage exhibited higher rates under twice-daily and daily irrigation, along with 50% and 75% light treatments compared to other conditions (P≤0.05). Notably, in the twice-daily irrigation setup, leaf area, registering at 22.83 cm², displayed a statistically significant variance from other treatments (P≥0.05). Leaf area peaked under 50%, 0%, and 75% light treatments (P≤0.05). Significant disparities were observed in all vegetative attributes between the initial 3-month and subsequent 3-month assessments in response to varying light and irrigation treatments. Furthermore, most growth parameters, excluding leaf count, showcased higher values in the initial 3-month assessment compared to the subsequent period. Notably, in the second 3-month evaluation, differences among treatments were less pronounced. Analysis revealed that, during the initial 3-month assessment, diameter growth peaked under twice-daily irrigation (0.41 mm), daily irrigation (0.36 mm), and 50% light exposure (0.32 mm). Conversely, in the subsequent 3-month period, disparities in diameter growth diminished, particularly in the 50%, 25%, and 75% light treatments, aligning them in comparable groups. Similarly, height growth attained its maximum under the twice-daily irrigation regimen during the initial 3-month assessment, recording 4.75 cm, which decreased to 2.41 cm in the subsequent 3-month period, aligning it with the once-daily irrigation scheme (2.21 cm). Height growth peaked at 50% light (4.48 cm) during the initial 3-month evaluation, transitioning to 75% light (4.34 cm) in the subsequent 3-month period. Distinctively, leaf number exhibited a contrasting trend, being lower in the initial 3-month period than in the subsequent phase, showcasing a unique pattern compared to the other vegetative parameters. Conclusion: Based on the study outcomes, grey mangrove seedlings demonstrate heightened sensitivity to light and irrigation during their initial 3-month growth phase, displaying more pronounced responses to these factors. Therefore, ensuring appropriate levels of irrigation and shade is paramount for fostering optimal growth conditions for grey mangrove seedlings in nursery settings. [ABSTRACT FROM AUTHOR] |
