Chlorophyll and proline contents on garlic leaves (Allium sativum L.) under biotic stress
B N Hidayah (a,*), M F Azhari (b), M W Y Perdana (b), M T Hamsyah (a), M Rani (a), Nurhaedah (a), Sirajuddin (a), I Gazali (a), Supardi (a), A Hafid (a), Mardiana (c), A Pramudia (d, e)

(a) Research Center for Horticulture, National Research and Innovation Agency (BRIN), Republic of Indonesia.
*baiq001[at]brin.go.id
(b) Alumni of the Faculty of Agriculture, Mataram University, Mataram, West Nusa Tenggara Province, Indonesia.
(c) Research Center for Social Welfare, Village, and Connectivity, National Research and Innovation Agency (BRIN) - Republic of Indonesia.
(d) Research Center for Climate and Atmosphere, National Research and Innovation Agency (BRIN), Republic of Indonesia.
(e) Innovation Center for Tropical Science (ICTS) Indonesia.

Abstract

Garlic plants (Allium sativum L.) located in the Sembalun highlands of Eastern Lombok have been affected by pink root and white rot diseases caused by Fusarium solani and Fusarium oxysporum fungi, respectively. These diseases have caused a physiological response in the plant leaves. This study aims to investigate the physiological response, such as changes in the chlorophyll and proline contents in garlic leaves, due to biotic stress caused by the attacking of these fungal pathogens. The research was conducted in July - August 2019. Plant samples were collected from a garlic cultivation center in the Sembalun highlands, East Lombok Regency, Nusa Tenggara Barat (NTB) Province of Indonesia. Chlorophyll and proline content measurements were conducted at the laboratory of West Nusa Tenggara Institute for Assessment of Agricultural Technology. The spectrophotometric measurement of chlorophyll content was based on the Lamber-Beer law, while the optical density of proline was measured with a spectrophotometer at a wavelength of 520 nm. The results showed that the highest decrease in chlorophyll content was present in plants affected by white rot disease with severe intensity. However, there was no significant effect on the proline content in plants affected by pink root and white rot diseases. This indicates that the biotic stress caused by these diseases influenced chlorophyll contents in garlic leaves, but not the proline contents. The decrease in chlorophyll content due to these diseases has disrupted the photosynthesis process, making it difficult for plants to grow optimally. This has also disrupted bulb formation and decreased plant yields.

Keywords: disease, pink root, white rot, Fusarium solani, Fusarium oxysporum

Topic: Agricultural Production