A Rare Abnormality in Male Inflorescence of Mulberry — A New Report
A. Tikader and K. Thangavelu
Central Sericultural Germplasm Resources Center
Hosur-635 109, Tamil Nadu, India
ABSTRACT
The genus Morus L. to which all the cultivated and wild mulberry belong, was established by Carolus Linneaus, the Swedish botanist and taxonomist in the 1753. The mulberry is the first plant where sex was demonstrated by Rudolf James Camerer, a German worker better known by the Latinized name Camerarius (1964), rediscovered sexuality in plants. To date the mechanism of sex expression in mulberry is not understood fully. Mulberry plants are generally dioecious but occurrence of monoecious plants is sporadic. However, unisexuality is more predominant and some plants produce all types of flowers. According to Mendez (1998) the probability of reproduction and the number of inflorescences produced increased with the plant size and the flower number (total male staminodes, female pistillodes) increased with both plant and inflorescence sizes. Bisexual flowers exist due to development of pistillode or staminodes (Mukherjee 1963, 1965). The existence of different floral structures indicate that original flowers were probably hermaphroditic and unisexuality occurred from reduction/suppression on sterility of either stamens or pistils (Alieve, 1974, Goethe, 1970). Differences in sex expression in mulberry was earlier reported (Hardner 1948). High temperature (28-35°C), long day and full day lights and C/N ration have favoured predominantly the female flower (Minamizawa 1963; Jolly et al. 1986). Physical injuries like pruning may also change the sex from male to female and vice versa. Various reports show that sex of particular species in mulberry is not a static phenomenon. It changes from season to season, depending upon fluctuations in environment, cultural practices, pruning and nutritional status of the soil. (Tikader et al. 1995).
INTRODUCTION
Metamorphosis of different floral organs have been reported by several authors. It was reported that all appendices of leafy shoot — leaves, bracts, sepals, petals, stamin and pistil are homologous (Goethe 1970). Any floral organ and even the ovule, may become leafy in form of colour (Meyer 1966). However, branching in male inflorescence is hitherto unknown. The present scientific . . . . . .
REFERENCES
ALIEVE MO. 1974. Fasciation of mulberry in polyploidy. Izv Nauk Az SSr Ser Bio Nauk 5(6): 52-57 (Rus).
CAMERARIUS RJ. 1694. Taxonomy of flowering plants. C. L. Porta, W.H. Freeman and Company, San Francisco, 13p.
GOETHE JW VAN. 1970. Versuch die metamorphose de pflanzen zu erklaren. Translated by Emily M. Cox 1893. Essay on the metamorphosis of plants. Journal of Botany 1: 327-374.
HARDNER R. 1948. Vegetative and reproductive development of Kalanchoe blossfel Diana as influenced by photoperiodism. Symp Soe Expl Biol 2: 117-137.
JOLLY MS, DANDIN SB, RAVINDRAN S, KUMAR R. 1986. Sexual polymorphism in genus Morus L. Proceedings of the Indian Academy of Sciences. (Plant Sciences) 96(4): 315-320.
MEYER VG. 1966. Flower abnormalities. The Botanical Review 32(1): 165-218.
MENDEZ M. 1988. Modification of phenotypic and functional gender in the monoecious Arum italicum (Araceae). American Journal of Botany 85(2): 225.
MINAMIZAWA K. 1963. Experimental studies on the sex differentiation in mulberry. Bull Fac Agric Tokyo Noko Digaku 7: 4-47.
MUKHERJEE SK. 1963. Occurrence of trifid and quadrifid, styled condition in mulberry (Abnormal carpellary condition in bicarpillate family). Indian Journal of Sericulture 1(3): 27-28.
MUKHERJEE SK. 1965. On some morphological evidences in floral structure towards the development of unisexuality in mulberry. Indian Journal of Sericulture 4: 1-7.
TIKADER A, VIJAYAN K, RAGHUNATH MK, CHAKROBORTI SP, ROY BN, PAVAN KUMAR T. 1995. Studies on sexual variation in mulberry (Morus spp.). Euphytica 84(2): 115-120.
WARDLAW CW. 1957. The floral meristem as a reaction system. Proc Roy Soe Edn. Sec 66: 394-408.
