Photosynthetic Characteristics and Productivity of the Coconut Palm

Abstract

Among the tree crops in the tropics the coconut palm occupies an important position as a food, oil, and fibre crop. Productivity of crop species depends on the combined effect of their genetic constitution, climate, nutrition and other biotic factors. To increase the productivity of the coconut palm it is necessary to have a basic understanding of physiological processes such as assimilation of carbon and growth in relation to climatic factors.In-situ photosynthetic measurement of coconut seedlings using Li-COR 6500 portable photosynthesis system revealed that their maximum photosynthetic capacity is attained at photosynthetic photon flux densities (PPFD) ranging from 1400-1700 u moles photons m' 2 S" 1 . The rate of apparent photosynthesis (A) of the coconut palm varies between 2-15 a moi C0 2 m" 2 S" 1 depending on leaf age, nutritional status .and climatic factors. The rate of leaf respiration was closely similar in young and older leaves ranging from -2 to -1 fi mol C0 2 m' 2 S"'. The measured light-use efficiency of the coconut palm was found to be 1.2 g MJ" 1 and the conversion efficiency of solar energy was approximately 2.4%.Water deficit is the major constraint causing wide fluctuations in photosynthesis. Due to height of trees, the leaves in the canopy are exposed to a high wind velocity as well as water and thermal stresses. As a result, under soil water deficit conditions coconut palms reduce excessive water loss and gaseous exchange by mid-day closure of stomata and maintain stomatal conductance at a lower level. However, the rate of apparent photosynthesis and the ratio of intercellular to ambient partial pressure of C0 2 (P/PJ are not decreased proportionately with the stomatal conductance.

Photosynthetic Assimilation, Carbohydrates in Vegetative Organs and Carbon Removal in Nut-Producing and Sap-Producing Coconut Palms

“…This continuous demand is met by the production of photo assimilates. Crop yields depend on the efficiency of dry matter production and its partitioning into economic produce; a phenomenon applicable to coconut as well (Jayasekara et al, 1996). Perennial plants accumulate non-structural carbohydrates in vegetative organs, during periods of excess production of photo assimilates, to be used when demand exceeds production (Dickson, 1991;Kozlowski, 1992).…”

Characterization of Annur and Bedakam Ecotypes of Coconut from Kerala State, India, Using Microsatellite Markers

“…The influence of seasonal variations on gas exchange characteristics and biochemical constituents of coconut palms in a particular area have also been reported in earlier studies [7][8][9][10]. Weather factors are known to influence crop production especially under rainfall condition and of all the climatic factors, rainfall has maximum influence on the seasonal variation in yield [11].…”

Cloning Coconut via Somatic Embryogenesis: A Review of the Current Status and Future Prospects

“…Prior to the commencement of acclimatization, exposure to a higher light intensity has been shown to improve the final survival rate of embryo culture-derived plantlets [84]. An appropriately high photosynthetic activity in natural-grown coconut seedlings was found at a photosynthetic photon flux density (PPFD) of ca.1400 to 1700 µmol m −2 s −1 , but it varied depending on leaf age, plant nutrition, and other climate variables [85]. Assy Bah et al, 1987 [86] used a light intensity of 3000 Lux (ca.…”