title: Fused lobed anther and hooked stigma affect pollination, fertilization and fruit set in mango: a scanning electron microscopy study.
abstract: Mango malformation is the most threaten disease that limits mango production, worldwide. For a long time, due to its complex nature, the cause and causal agents were strongly disputed. Diverse Fusaria, including Fusarium mangiferae, are known to be associated with the disease. There are indications that augmented level of endogenous ethylene in response to various abiotic and biotic stresses alters the morphology of reproductive organs. Here, scanning electron microscopy (SEM) of healthy and malformed reproductive organs of mango cv. Baramasi was performed to compare the functional morphology. The SEM study revealed that anthers of hermaphrodite healthy flowers were bilobed with large number of turgid pollen grains whereas malformed flowers showed fused lobed anthers with scanty deformed pollen grains. Furthermore, the stigma of healthy flowers exhibited a broad landing pad as compared to malformed stigma which showed hooked and pointed tip. All these impaired morphology of male and female reproductive organs lead to failure of sexual reproduction. This is the first evidence to show fused lobed anther with impaired pollen grains and hooked stigma with poor stigmatic receptivity are mainly responsible for restricting the pollen germination and pollen tube growth. Here we suggest that abnormal development of anthers and pistils is due to endogenously produced stress ethylene. Further, added load of cyanide, a byproduct of ethylene biosynthesis, may also contribute to the development of necrosis which lead to desiccation of anther and pistil during hypersensitive response of plants.
authors.affiliation: Department of Plant Physiology; College of Basic Sciences and Humanities; G.B. Pant University of Agriculture and Technology; Uttarakhand, India.
authors.forename: Varsha
authors.initials: V
authors.lastname: Rani
authors.forename: Mohammad Wahid
authors.initials: MW
authors.lastname: Ansari
authors.forename: Alok
authors.initials: A
authors.lastname: Shukla
authors.forename: Narendra
authors.initials: N
authors.lastname: Tuteja
authors.forename: Gurdeep
authors.initials: G
authors.lastname: Bains
mesh_terms: D005030:Ethylenes / Q000378:metabolism*; D035264:Flowers; D005638:Fruit; D031022:Mangifera; D008855:Microscopy, Electron, Scanning; D010935:Plant Diseases / Q000382:microbiology; D011058:Pollen; D054817:Pollination; D012098:Reproduction
chemical_list: D005030:Ethylenes; C036216:ethylene
keywords: Anther; mango malformation; pollen; scanning electron microscopy; stigma; stress ethylene