Phenology of flowering and fruiting and effect of KNO₃ and H₂O₂ on germination process of <i>Amorphophallus muelleri</i> Blume

Abstract

Amorphophallus muelleri Blume also known as Indonesian Konjac (IK, in short) is a wild plant that spreads out in Indonesia especially in the southern part. The genus Amorphophallus can also be found in some countries in South-East Asia. The IK tuber contains glucomannan, a compound which has high economic value as raw material in many industries such as food, drink, pharmacy, cosmetics, paper, rubber, textile, film industries and many others. The plant is easy to cultivate. Due to the economic benefit of IK tubers and to the easiness of its cultivation, this study was carried out to increase the productivity of glucomannan. The current productivity is still low compared to foreign demand. For example, in 2020 alone, according to the Ministry of Agriculture, Republic of Indonesia, only 12 % of foreign demand have been fulfilled. Therefore, there is an urgent need to increase the productivity of IK tubers. This is the main problem of this research. Its objectives were two-fold. First, was to study the effect of tuber weight on flowering percentage, flower size, and fruiting which is represented by the number of fruits and the number of seeds. Second, was to find out the right concentration of KNO₃ and H₂O₂ solutions as well as the soaking time in those solutions to break the dormancy period and to increase the germination rate. For these purposes, a laboratory experiment using completely randomized design with three treatments was conducted and the collected data were analyzed using general linear model, analysis of variance and multiple comparison test. The results indicate that the tuber weight significantly affects the flowering percentage, flower size, number of fruits and number of seeds of IK. The heavier the planted tuber, the higher the flowering percentage and the larger the flower size, number of fruits and number of seeds. The response on dormancy breaking treatment indicates that there is no significant effect of soaking treatment in KNO₃ and H₂O₂ solutions on dormancy period of the IK seeds. The KNO3 and H₂O₂ solutions have only effect on increasing the germination rate and on shortening the time period for seeds to germinate. Moreover, unlike H₂O₂, there is no residual effect of KNO₃ on seeding growth, and on weight and shape of the IK tuber. To the knowledge of the authors, these findings are unprecedented and could thus, contribute to the literature.