Anatomical aspects of the ginger flower Etlingera elatior (Jack.) RM Smith, acclimatization with the usage of different nutritive solutions
The Ginger flower, Etlingera elatior (Jack.) RM Smith (also known as torch ginger, ginger flower, red ginger lily, torch lily, wild ginger), belonging to the Zingiberaceae family, stands out with one of the main ornamental tropical species. The objectives of the present study were to establish an acclimatization methodology for in vitro cultivated cane seedlings, and to compare the internal structure of leaves of seedlings submitted to different nutrient solutions. The seedlings from the in vitro culture were transplanted into trays with inert substrate (expanded vermiculite + 10% sand), where they remained in a growth room with controlled temperature of 25 ± 2 °C and photon irradiance of 67 μm m-2 s-1. Moisture control was carried out by using a transparent plastic bag, which was removed after 15 days and shortly thereafter, the experiments were started with the use of nutritive solutions MS (Murashige & Skoog), BJ (Bolle-Jones) and HO (Hoagland & Arnon) at 35% of their ionic strength. For the anatomical study, transverse and paradermal sections were realized in the foliar laminae of seedlings in vitro, in period of acclimatization and in plants already established. The in vitro seedlings showed survival at 100% when transferred to the ex vitro condition. In the cross sections and leaf parser, anatomical differences between the seedlings of the different environments were observed. The abaxial and adaxial epidermis presented significant differences in the environments in which the seedlings developed, showing themselves to be thicker as the acclimatization period increased. The thickness averages of the palisade parenchyma did not differ statistically in the acclimatization periods and in the different nutrient solutions tested. On the other hand, those ones of the spongy parenchyma´s presented significant differences in relation to the nutrient solutions tested, evidencing in all evaluations the MS solution, which contributed the most to the development of the internal structures of the leaf (spongy parenchyma and central vascular cylinder). The highest stomatal density was observed in seedlings developed in vitro (250 stomata per mm2) when compared to those ones already acclimatized or even to that one of field, 200 and 190 stomata per mm2 respectively. The stomata of the Ginger flower leaves developed in vitro presented with polar and equatorial diameters greater than the stomata of leaves already acclimatized and as well as of field.