Fruit and Seed Morphometry and in Vitro Germination of Hollyhock Seeds

Abstract

Alcea rosea L. is an ornamental shrubs that has many possible uses, including medical purposes. This species is mainly propagated by seeds, however, there are few studies that describe their morphometric characteristics, in addition, previous reports show that they have dormancy that makes the germination difficult. Therefore, this work aimed to determine the morphological characteristics of the fruit and seeds of A. rosea and to evaluate its in vitro seeds germination under different pregerminative methods in different culture media. For the morphological description, 25 fruits or seeds were evaluated. For the in vitro germination in the MS and WPM culture media, the pregerminative treatments were: T1 - untreated seeds (control); T2 - mechanical scarification (cut in the seed coat); T3 - thermal scarification (immersion of the seeds in water at 60 ºC for 16 min). The experimental design was completely randomized, in a 3x2 factorial scheme (pregerminative treatments x culture media), with eight replications and twenty seeds per replication. A visual scale was proposed to classify the seedlings vigor. The schizocarp hollyhock fruit is flattened and its diameter is greater than its height, and each fruit contains 33 seeds, on average. The seeds have approximately 4.2 mm in length and 100 seeds weight, on average, 0.89 g. The culture medium does not influence the seeds germination and the pregerminative treatments are not necessary for the germination. However, the mechanical scarification promoted the best germination speed index and the production of more vigorous plants.