Physio-anatomic aspects on the initial growth of Guazuma ulmifolia Lam. seedlings (Sterculiaceae)

Silvana P Q Scalon,Jocemar J Silva,Roseli Betoni,Heloisa H G Pereira,Daniele F Glaeser,Rosilda M Mussury

doi:10.1590/s0001-37652011000200027

Silvana P Q Scalon, Jocemar J Silva + Show 4 more

Open Access

https://doi.org/10.1590/s0001-37652011000200027

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Abstract

This paper aimed to evaluate the initial growth of "mutambo" seedlings in different conditions of light intensity and treatments with gibberellic acid (GA). The seedlings were kept under full sun and 50% of shading. Sixty days after the emergence, seedlings were sprayed with: 1) 100 mg L(-1) GA(3); 2) 200 mg L(-1) GA(3); 3) control. At the end of the appraisals, seedlings height under 50% of shading was compared to the height that were growing under full sun with 200 mg L(-1) GA. Stem diameter was lower under shading. Leaf area did not vary among the treatments, but the root system growth was higher under full sun and did not vary among GA levels. The number of stomata, trichomes and epidermal cells on adaxial and abaxial sides was higher under full sun. Total dry masses of leaf and root were highe runder full sun and with 200 mg L(-1) GA application. "Mutambo" seedlings presented a higher initial growth under full sun, although with a lower height, diameter, and lenght of the largest root and total dry masses of leaf and root were higher. A concentration with 200 mg L(-1) promoted a higher growth.

Highlights

The use of native tree species in reforestation programs with sustainable management or for urban plantation has been intensified lately
These need some luminous requirements for their development and the seedlings can use light to better develop in places with a high light intensity as in big glades, while other species have a better development in shading under woods
Few information was found in the inquired bibliography about leaf anatomy and seedlings production of “mutambo”, so this paper aimed to evaluate the initial growth of its seedlings under different conditions of light intensity and the results of gibberellin application on its leaf anatomy

Summary

Introduction

The use of native tree species in reforestation programs with sustainable management or for urban plantation has been intensified lately. According to Stefanini et al (2002), gibberellin effects on seedlings can be noticed on stem elongation, internode lenght, leaf area and growth of dry mass. These effects promote cell division and elongation and, the plant in-. Light plays an important role in the development of forest species. These need some luminous requirements for their development and the seedlings can use light to better develop in places with a high light intensity as in big glades, while other species have a better development in shading under woods. Howard (“sombreiro”) presented higher height and bigger root dry mass under full sun, while in Peltophorum dubium (Sprengel) Taubert (“canafístula”) a significant difference for root height and length was not noticed, it presented bigger root dry mass un-

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