Scientific Correspondence

CURRENT SCIENCE, VOL. 104, NO. 4, 25 FEBRUARY 2013 426 is, thus, simultaneous with or occurs immediately before anthesis (Figure 1 c– f ). (ii) In some flowers opening initiates by the expansion of the apices of the tepals, the stimulus of which then spreads laterally (Figure 1 a and b). However, what is interesting to note is that the anthers are still in an undehisced state. It takes more than 24 h for these anthers to dehisce. About 20% of plants in a population show the dual mode of anther dehiscence. The frequency of such flowers per plant varies between 20% and 30%. It takes about 4–6 days for the male flowers to empty their contents. It is quite possible that the two distinct patterns of anthesis are adapted to two modes of pollination; the lateral opening probably catering to the needs of wind pollination and apical opening for biotic/ insect pollination. Even though flowers are inconspicuous and unattractive, a number of diverse visitors like ants, bees, houseflies and sparrows frequent the flowers for different purposes. Bees visit in the morning up to noon; duration of each visit is brief, lasting 6 sec. Ants feed on pollen and houseflies are just casual visitors. Sparrows probably prey on the aphids found in the inflorescences. Therefore, the actual role of insects in pollen transfer remains to be determined. It is equally likely that the buds with apical anthesis are not able to empty their pollen compared to the ones with lateral opening. This is largely on account of mechanical reasons. There is a considerable space constraint inherent in the floral architecture itself. Presence of bract on one side and floral axis on other apparently keeps the flowers snuggled/squeezed. Anthers after dehiscence unload their contents inside the tepal cavity. Since the tepal opens from the top, only strong wind can take out the pollen. However, those which open laterally have two slits, one on each side. A mild breeze is enough to allow the pollen of such flowers to be carried away. Male flowers usually differentiate on young shoots which are exserted and tend to be away from the plant body proper (Figure 1 l). This is an adaptation to ensure effective pollen dispersal even in small wind currents. Continuous motion of extruded young shoots on slight disturbance or slow wind facilitates pollen dispersal. Had they been amidst the older shoots, dispersal to neighbouring female plants probably would have been hampered. Female flowers also vary in their behaviour vis-à-vis exposing their stigmas. (a) In nearly 30–40% of flowers in a population, female flowers have a persistent perianth. From this tightly closed perianth the stigma grows and protrudes out at the time of anthesis (Figure 1 j and k). (b) In many flowers, the perianth withers at an early stage of development leaving behind a naked flower bud and the emergence of stigma marks the beginning of anthesis (Figure 1 i). Under such circumstances, it becomes difficult to ascertain the exact stage of anthesis. However, stigma becomes receptive 24 h after extrusion or opening and is at its peak 72–96 h after anthesis. Female flowers protected by the perianth are at advantage because at the time of anthesis (14–27 April), the climate of Ladakh is harsh and stigmas are susceptible to desiccation. On the other hand, in flowers where the protruding stigmas are protected by the bracts, the bracts bend at the receptive stage (Figure 1 j and k) when the stigma attains a length of approximately 2 mm in 3–4 days (Figure 1 h). 1. Chaurasia, O. P. and Singh, B., Cold Desert Plants, Vol. I, Field Research Laboratory (DRDO), Leh, Ladakh, 1998. 2. Chaurasia, O. P., Basant, B., Verma, A., Ahmad, Z. and Raut, B., Potential Fodder Plants of Ladakh, Field Research Laboratory (DRDO), Leh, Ladakh, 2003–04. 3. Singh, L., Ali, A. and Kumar, S., J. Plant Dev. Sci., 2010, 2, 147–149. 4. Rousi, A., Ann. Bot. Fenn., 1971, 8, 177– 227. 5. Code, D., Seabuckthorn – Ancient food of east and future food of west. www. seabuckthorn.com 6. Lu, R., Seabuckthorn: A multipurpose plant species for fragile mountains. International Centre for Integrated Mountain Development, Katmandu, Nepal, 1992. 7. Yao, Y. and Tigerstedt, M. A., Euphytica, 1994, 77, 165–169. 8. Li, T. S. C. and Schroeder, W. R., Hortic. Technol., 1996, 6, 370–386. 9. Li, T. S. C., In Functional Foods – Biochemical and Processing Aspects, Technomic Publ Co Inc., Lancaster, PA, USA, 1999, pp. 329–356. 10. Li, T. S. C., In Trends in New Crop and New Uses (eds Janick, J. and Whiphey, A.), ASHS Press, Alexandria, VA, USA, 2002, pp. 393–398. 11. Small, E., Catling, P. M. and Li, T. S. C., Seabuckthorn (Hippophae rhamnoides) An ancient crop with modern virtues; www.seabuckthorn.com