Physical-Anatomical and Initial Growth of Tabebuia roseoalba (Ridl.) under Different Water Regimes

Silvana De Paula Quintão Scalon,Rosilda Mara Mussury

doi:10.1590/2179-8087.056117

Silvana De Paula Quintão Scalon, Rosilda Mara Mussury

Open Access

https://doi.org/10.1590/2179-8087.056117

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Abstract

The present work evaluated the physical-anatomical and initial growth of Tabebuia roseoalba seedlings exposed to different water regimes. The seedlings were grown under 100, 50, 25 and 12.5% of the water retention capacity (WRC). After 90 days, the following aspects were evaluated: height, diameter, fresh and dry weights of aerial and root, root length, and leaf area, Dickson quality index, liquid assimilation rate, relative growth rate, specific leaf area, stomatal index, and number of trichomes and leaf epidermal cells. The results indicated seedlings have greater initial growth and quality when cultivated at 100% WRC, and 25 and 12.5% WRC represented stress conditions for the plants. The species is hypostomatous with anomocytic stomata. The number of stomata, the stomatal index, and the number of epidermal cells did diminish with reduced water availability. The number of trichomes were larger on the adaxial face as water availability decreased.

Highlights

IntroductionUnder conditions of low soil water availability, some metabolic processes are affected, with the partial or total closing of the stomata to limit water loss and consequent reduction in CO2 acquisition, which can lead to negative growth affects – including reduction of leaf expansion
Introduction and objectivesOne of the greatest difficulties to cultivate native species is the available water in the soil, and there are few studies demonstrating this availability in the soil and its transfer to the plants, which can affect the establishment of individuals (Chirino et al, 2017).Under conditions of low soil water availability, some metabolic processes are affected, with the partial or total closing of the stomata to limit water loss and consequent reduction in CO2 acquisition, which can lead to negative growth affects – including reduction of leaf expansion
The average values of the fresh and dry weights of the aerial portions and roots of T. roseoalba seedlings were lower under conditions of restricted water availability, with fresh weight of the aerial portion (FWAP) values being 73% and 92% lower under 25% and 12.5% water retention capacity (WRC) respectively, while FWRP, dry weight of the aerial portion (DWAP) and DWRP values were 50% lower on the average (Table 1), indicating that the T. roseoalba aerial portion was more influenced by water deficit conditions than the root system

Summary

Introduction

Under conditions of low soil water availability, some metabolic processes are affected, with the partial or total closing of the stomata to limit water loss and consequent reduction in CO2 acquisition, which can lead to negative growth affects – including reduction of leaf expansion. It can accelerate their senescence and abscission (which will directly affect photosynthesis), leaf abscission, inhibiting the internodes elongation and affecting root and shoot growth, the increased deposition of wax and increased trichome growth on the leaf surfaces (Jeromine et al, 2019; Scalon et al, 2011; Rosa et al, 2017; Silva et al, 2016). The recommended mixture for seedling production (soil + sand + semi-decomposed chicken-bed wastes) promotes good seedling heights, radical-hypocotyl transition zone diameters, chlorophyll indices, leaf areas, root lengths, and dry weights of both the aerial and root portions (Macedo et al, 2011).

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