Influence of growth regulators on flowering and Fruiting in in <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
JATROPHA CURCAS: a bio-diesel plant
Engery Plantation Demonstration project and <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Biotechnology Center.
Bio-Technology Lab Department of Botany
University of Rajasthan, Jaipur - 302 004
ABSTRACT: Jatropha curcas produces flower twice in a year but flowering in June July comes to fruiting in greater numbers as compared to winter flowering. The mature bunch of flowers contains around 90 percent male flowers while the remaining 10 percent flowers are female. Out of this only 40 percent flowers produce viable seeds Thus there is need to improve the flowering and fruiting ration. Present study was aimed to increase total oil yield of Jatropha curcas. The application of nutrients improved plant growth but it did not improve the flowering. An attempt was made to improve flowering and fruiting. The GA3 supported maximum above ground plant height and fresh weight and biomass yield of the plant while the auxins (NAA and IAA) promoted growth and biomass yield over control. Application of GA3 improved flowering in the plant. The application of growth regulators not only improved the flowering and fruiting but it also improved the oil yield.
Keywords: Biomass resource, Biomass production, Biodiesel.
The plant is found wild in several parts of the world and has been cultivated successfully in Mali, Central America, Guatemala, Indonesia, Senegal and Zambia. In India Govt of India Department of Biotechnology, has supported Jatropha Plantations under macromission project of planning commission.
In India it is largely confined to hilly areas and in Rajasthan its spreaded in over 9000 sq km mainly in Udaipur division. The plant grows south east of Aravallis while attempts to raise its plantations north east of Aravallis have not been reported with success.
Apparently plant can grow in areas with minimum rainfall of 300 mm but for flowering and fruiting it needs minimum rainfall of 600 mm per annum. Besides it need humid atmosphere at the time of flowering. The flowers shrivel and fall if the flowering is followed by dry season. Besides older plants are able to bear more fruits under natural conditions on slopes then in the flat grounds. The plant is mainly grown on hedges.
It is a small tree or shrub with smooth gray bark, which exudes whitish colored, watery, latex when cut. Normally, it grows between three and five meters in height, but can attain a height of up to eight or ten meters under favorable conditions.
It has large green to pale-green leaves, alternate to sub-opposite, three-to five-lobed with a spiral phyllotaxis. The petiole length ranges between 6-23 mm. The inflorescence is formed in the leaf axil. The plant can be grown without fertilizer, but for getting a better yield, the fertiliser mixture of NPK ( 15:15:15) may be applied at the rate of 250 g per plant at the onset of the rainy season every year.
Flowering and fruiting habit
The trees are deciduous, shedding the leaves in the dry season. Flowering occurs during the wet season and two flowering peaks are often seen. In permanently hu-mid regions, flowering occurs throughout the year. The seeds mature about three months after flowering. Early growth is fast and with good rainfall conditions nursery plants may bear fruits after the first rainy season, direct sown plants after the second rainy season. The flowers are pollinated by insects especially honey bees. J. curcas is a perennial, deciduous shrub or treelet. It flowers during the rainy season with concentrated flowering from late July to late October. The plant produces flowers in racemose inflorescences, with dichasial cyme pattern. The flowers are unisexual, and male and female flowers are produced in the same inflorescence. Normally, the inflorescences produce a central female flower surrounded by a group of male flowers. In a few, the places where female flowers are expected are substituted by male flowers. Numerically, 1–5 female flowers and 25–93 male flowers are produced per inflorescence. The average male to female flower ratio is 29 : 1. However this varies with the climatic, edaphic and nutritional conditions.
Fruit: Each inflorescence yields a bunch of approximately 10 or more ovoid fruits. Three, bi-valved cocci are formed after the seeds mature and the fleshy exocarp dries. The seeds become mature when the capsule changes from green to yellow, after two to four months.
The petiole length ranges between 6-23 mm. The inflorescence is formed in the leaf axil. Flowers are formed terminally, individually, with female flowers usually slightly larger and occurs in the hot seasons. In conditions where continuous growth occurs, an unbalance of pistillate or staminate flower production results in a higher number of female flowers.
The individual flowers are grouped together in the racemose inflorescences, an arrangement which promotes attraction and foraging rate by the foragers. The plant with monoecious sexual system essentially requires an agent for pollen transfer from male to female flowers, within or between conspecific plants. The floral rewards in both flower sexes are accessible even to short-tongued anthophilous insects. The bees, by collecting pollen and nectar and by moving between male and female flowers within and on different conspecific plants, effect pollination in a messy and soiled manner
The flies also exhibit the same foraging behaviour and effect pollination. Ants and thrips remain on the same plant and effect geitonogamy only. Although all insect species effect pollination, only bees and flies effect xenogamy. The flies are represented by only one species, Chrysomya, and they are underrepresented among the pollinators. They generally utilize many different sources of food, and usually their pollinator activity is unreliable. The proximity of a suitable breeding ground, frequent wet, decaying vegetable and dung material is important for their presence in the vicinity of J. curcas. Flies, especially small-bodied Musca, Eristalis, etc., which have small-distance flight range, play an important role in pollination. The production of female flowers in small number, surrounded by a large number of male flowers in J. curcas seems to be a strategy to ensure pollination to the maximum extent.
(A) Area of plant collection:
Initial plant material was collected from Udaipur division. The climate of Udaipur is a tropical one. The summer season is tolerably hot, with the average temperature hovering around 38.3° C (max) to 28.8° C (min). The climatic conditions of Udaipur, Rajasthan are quite pleasant in winters. The average temperature falls in the range of 28.3° C (max) to 11.6° C (min). Udaipur weather experiences scanty rainfall in the monsoon season, somewhere around 61 cm, approximately. In summers Udaipur has temperature between 28.8° C to 38.3° In Winters Udaipur has temperature between 11.6° C to 28.3° C.
(B) Area of experimentation-
Four accessions having oil contents more than 35 percent were selected for multiplication at the Energy Plantation Demonstration Centre, University of Rajasthan, Jaipur under Department of Biotechnology supported micro mission programme. Jaipur has hot and scorching summers and cool winters, which are pleasanter. The mercury rises to as high as 45 °C in summers, when the minimum temperature is 25.8 °C. In winters the maximum temperature restricts itself to about 22 °C. However, nights can be cold and temperature can be as low as 8.3 °C. Jaipur Soil is Yellowish Brown and Non-Calcil Brown. Red and Yellow Soil are poorer in carbonate and humus content. Calcium carbonate is absent. Salt content is low.
The geitonogamy was tested by pollinating the female flowers with the pollen of male flowers of the same plant and xenogamy by pollinating the female flowers with the pollen of male flowers from a different conspecific plant. Seventy-eight female flowers, six each from thirteen plants were used for geitonogamy and one hundred and four female flowers, eight each from thirteen
plants for xenogamy.
2.1 Effect of Growth regulators:
Different growth regulators like CCC, 2,4-5 T, GA3
IAA, and NAA were sprayed at the concentration of 50 ppm six times at fortnightly interval. The results are recorded after 15 days of last spray.
2.2 Effect of GA3
The plants were sprayed with aqueous solution of GA3 (0.0; 10 ppm; 50 ppm; 100 ppm) at fortnightly intervals for three months and readings were recorded after forthnight of last spary.
3 RESULTS AND DISCUSSION.
3.1 The Flowering in the Udaipur division takes place thrice in a year i.e. March-April; July-October and finally in November-December period.
3.2 Fruiting takes place mainly in the flowers produced in July-October period. Flowers of March -April get shriveled due to excessive heat in the ensuing months.
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Figure2: Effect of growth regulators on Jatropha curcas plants.
3.3 Effect of GA3:
The plants were sprayed with aqueous solution of GA3 (0.0; 10 ppm; 50 ppm; 100 ppm) at fortnightly intervals for three months and readings were recorded after forthnight of last spary. Spray of growth regulators resulted in elongation of branches and in our experiment and the plants did not bears fruits in the third year. A very less number of flowers which developed on branches shriveled . Attempts are being made to study the fruit bearing pattern of the plants at the EPDPc.
Mango is reported to have good bearings in alternate years. Does Jatropha curcas has the same pattern of fruit bearing ? The native people have also reported that fruit bearing in Udaipur region in Jatropha is highly dependent of good monsoon and it is generally very heavy every alternate years.Spray of growth regulators resulted in elongation of branches and in our experiment and the plants did not bears fruits in the third year. A very less number of flowers which developed on
3.4 Effect of growth regulators: Different growth regulators like CCC, 2,4-5 T, GA3 IAA, and NAA were sprayed at the concentration of 50 ppm six times at fortnightly interval. The results are recorded after 15 days of last spray (e.g. Fig. 2). Only slight increament was recorded in plants sprayed with 2,4-5 T and CCC. GA3 Spray resulted in maximum increase in height which was followed by IAA and NAA.
Figure2: Effect of growth regulators on Jatropha curcas plants.
Effect of growth regulators. (50ppm)
Table I: Effect of different growth regulators on growth of Jatropha curcas.
The award of research project to Professor Ashwani Kumar by Department of Biotechnology,Govt of India is gratefully acknowledged.
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