Response of Gas Exchange Activity and Relative Water Content of Neem in Relation to Weather

Abstract

Neem is known for its medicinal values and is a hardy plant that can grow in a wide variety of environmental conditions. However, productivity is impacted by unfavourable weather conditions due to different geographical locations. The present study was conducted to study the influence of prevailing weather conditions on certain physiological parameters deciding the reproductive ability of neem trees. The study was conducted in two different locations at different agro-climatic regions of Tamil Nadu, India. Gas exchange parameters like photosynthetic rate, stomatal conductance, transpiration rate and leaf temperature and relative water content during pre-flowering, flowering and post-flowering stages were measured and correlated with temperature, relative humidity, precipitation and wind speed observed from the corresponding location. In both locations, the neem trees recorded significantly higher values for these physiological parameters during the pre-flowering and fruiting stages compared to the flowering stage. The trees with higher Diameter and breast height (DBH) showed higher values for gas exchange parameters compared to the trees with lower DBH.

Weather Influences on the Gas Exchanges of Neem Trees

“…When the transpiration rate increases, the gas exchange activities tend to increase but based on the other environmental conditions like soil moisture status, temperature, relative humidity the photosynthetic rate may increase or decrease. The present study supported by had already been reported in [14] that weather variables such as rainfall and temperature affect photosynthesis, transpiration, and Stomatal conductance in neem tree.…”

“…Similar observation was found by [13]. In general, the transpiration rate had a positive association with photosynthesis and was an indirect indication of the rate of photosynthesis in leaves [14].…”

Weather induced physiological responses on the flowering habits of neem trees (Azadirachta indica)

“…These findings are in line with Sajjadinia et al, (2010) in Pistachio trees, who inferred that the variation in temperature and solar radiation between the pre-flowering and flowering phases may likely to contribute the observed differences in RWC. Pugazenthi et al, (2021) inferred that rainfall during the flowering would increase the RWC of neem trees.…”

“…Among weather parameters, rainfall positively influences RWC and temperature influences the gas exchange activities which favourably influenced the flowering, fruit formation and yield of neem trees (Pugazenthi et al, 2021). Results indicated that the soil moisture (SM) favoured the positive physiological responses that favouring neem tree flowering and reduced the stress inducing proline content.…”

“…Although there have been anecdotal reports from farmers and academia on the impact of weather parameter on neem growth and yield, there is currently a lack of scientific studies specifically investigating this phenomenon. In this context, a study was undertaken at Tamil Nadu Agricultural University, Coimbatore by Pugazenthi et al, (2021). In light of this, the study objective was set to investigate the weather-induced physiological responses in three flowering habituated (flowering, dormant flowering and alternating flowering) neem trees in Tamil Nadu.…”