Responses of Jatropha curcas L. to water stress

Research on production of Jatropha curcas focus mainly on its suitability to dry and and lands; whereas less attention has been paid to its production under high water availability. The growth performance of a drought tolerant plant such as J. curcas under different watering regimes was studied to...

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Main Author:	Kevin Muyang Tawie, anak Sulok
Format:	Thesis
Language:	English
Published:	2010
Subjects:	SB Plant culture
Online Access:	http://ir.unimas.my/id/eprint/8303/1/Kevin.pdf
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spelling	my-unimas-ir.83032023-06-20T03:13:02Z Responses of Jatropha curcas L. to water stress 2010 Kevin Muyang Tawie, anak Sulok SB Plant culture Research on production of Jatropha curcas focus mainly on its suitability to dry and and lands; whereas less attention has been paid to its production under high water availability. The growth performance of a drought tolerant plant such as J. curcas under different watering regimes was studied to investigate the influence of both high and reduced water availability on the various morphological and physiological traits that could contribute to an understanding of the effects of water stress on the plant. The experiment was a completely randomized design (CRD) with 4 treatments replicated 3 times )Each replicate consisted of 2 plants with a total of 24 plants altogether. Treatments were: (i) Rainfed (WO) - Plants watered at field capacity > -0.03 MPa, (ii) Mild water stress (W1) - Water maintained at soil water potential between > -0.10 and > -0.30 MPa, (iii) Moderate water stress (W2) - Water maintained at soil water potential between > -0.80 and > -1.0 MPa, and (iv) Extreme water stress (W3) - Water maintained at soil permanent wilt point >-1.50 MPa. The well-watered plants responded by showing significantly (p < 0.05) better height, greater proportion of inflorescence and fruits, comparatively larger fruits and more mass in seeds, higher leaf stomatal density and bigger leaf area growth. Number of inflorescences, amount of fruits, fruit size, seeds mass, and leaf stomatal density were increased by 31,54,90,3, and 69 % respectively in plants grown under well-watered conditions. Photosynthesis rates (A), stomatal conductance (gs), and transpiration (E) of the control was significantly (p < 0.05) higher than its water-stressed counterparts. However, water use efficiency for WO and W3 showed insignificant difference probably due to W3 adaptive capability to water deficits. Strong correlations were established between leaf stomatal conductance with both photosynthetic rates (r2 = 0.86) and volumetric soil water content (r2 = 0.89). Furthermore, foliar abscisic acid (ABA) was significantly correlated to stomatal conductance (r2 = 0.96) and volumetric soil water content (r2 = 0.83). Extreme water stress increased foliar ABA by 5-folds which in turn reduced stomatal conductance and thus decreasing photosynthesis rates. As an indicator for water stress, foliar spectral analysis showed low reflectance which attributed primarily to absorption by higher concentration of chlorophyll photosynthetic pigments and the presence of cytoplasmic fluid at the leaf cellular level. Strong significant I11 correlations were achieved by the reflectance indices such as the reflectance at 550 nm (R550)s, tructure independent pigment index (SIPI), and photochemical reflectance index (PRI) to leaf photosynthetic pigments indicating the depression caused by drought to chlorophyll concentrations in leaves. Overall, the well-watered plants at soil water field capacity (-0.03 MPa) showed better morphological and physiological responses whereby the positive effect has been very favaourable in terms of its flowering and fruiting due to the plant's potential to produce biofuel. Universiti Malaysia Sarawak, (UNIMAS) 2010 Thesis http://ir.unimas.my/id/eprint/8303/ http://ir.unimas.my/id/eprint/8303/1/Kevin.pdf text en validuser masters Universiti Malaysia Sarawak, (UNIMAS) Faculty of Resource Science and Technology.
institution	Universiti Malaysia Sarawak
collection	UNIMAS Institutional Repository
language	English
topic	SB Plant culture
spellingShingle	SB Plant culture Kevin Muyang Tawie, anak Sulok Responses of Jatropha curcas L. to water stress
description	Research on production of Jatropha curcas focus mainly on its suitability to dry and and lands; whereas less attention has been paid to its production under high water availability. The growth performance of a drought tolerant plant such as J. curcas under different watering regimes was studied to investigate the influence of both high and reduced water availability on the various morphological and physiological traits that could contribute to an understanding of the effects of water stress on the plant. The experiment was a completely randomized design (CRD) with 4 treatments replicated 3 times )Each replicate consisted of 2 plants with a total of 24 plants altogether. Treatments were: (i) Rainfed (WO) - Plants watered at field capacity > -0.03 MPa, (ii) Mild water stress (W1) - Water maintained at soil water potential between > -0.10 and > -0.30 MPa, (iii) Moderate water stress (W2) - Water maintained at soil water potential between > -0.80 and > -1.0 MPa, and (iv) Extreme water stress (W3) - Water maintained at soil permanent wilt point >-1.50 MPa. The well-watered plants responded by showing significantly (p < 0.05) better height, greater proportion of inflorescence and fruits, comparatively larger fruits and more mass in seeds, higher leaf stomatal density and bigger leaf area growth. Number of inflorescences, amount of fruits, fruit size, seeds mass, and leaf stomatal density were increased by 31,54,90,3, and 69 % respectively in plants grown under well-watered conditions. Photosynthesis rates (A), stomatal conductance (gs), and transpiration (E) of the control was significantly (p < 0.05) higher than its water-stressed counterparts. However, water use efficiency for WO and W3 showed insignificant difference probably due to W3 adaptive capability to water deficits. Strong correlations were established between leaf stomatal conductance with both photosynthetic rates (r2 = 0.86) and volumetric soil water content (r2 = 0.89). Furthermore, foliar abscisic acid (ABA) was significantly correlated to stomatal conductance (r2 = 0.96) and volumetric soil water content (r2 = 0.83). Extreme water stress increased foliar ABA by 5-folds which in turn reduced stomatal conductance and thus decreasing photosynthesis rates. As an indicator for water stress, foliar spectral analysis showed low reflectance which attributed primarily to absorption by higher concentration of chlorophyll photosynthetic pigments and the presence of cytoplasmic fluid at the leaf cellular level. Strong significant I11 correlations were achieved by the reflectance indices such as the reflectance at 550 nm (R550)s, tructure independent pigment index (SIPI), and photochemical reflectance index (PRI) to leaf photosynthetic pigments indicating the depression caused by drought to chlorophyll concentrations in leaves. Overall, the well-watered plants at soil water field capacity (-0.03 MPa) showed better morphological and physiological responses whereby the positive effect has been very favaourable in terms of its flowering and fruiting due to the plant's potential to produce biofuel.
format	Thesis
qualification_level	Master's degree
author	Kevin Muyang Tawie, anak Sulok
author_facet	Kevin Muyang Tawie, anak Sulok
author_sort	Kevin Muyang Tawie, anak Sulok
title	Responses of Jatropha curcas L. to water stress
title_short	Responses of Jatropha curcas L. to water stress
title_full	Responses of Jatropha curcas L. to water stress
title_fullStr	Responses of Jatropha curcas L. to water stress
title_full_unstemmed	Responses of Jatropha curcas L. to water stress
title_sort	responses of jatropha curcas l. to water stress
granting_institution	Universiti Malaysia Sarawak, (UNIMAS)
granting_department	Faculty of Resource Science and Technology.
publishDate	2010
url	http://ir.unimas.my/id/eprint/8303/1/Kevin.pdf
_version_	1783727980019712000

Responses of Jatropha curcas L. to water stress

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