Genomics and Applied Biology 2015, Vol. 6, No. 4, 1-6
1
Research Report Open Access
Changes in Proline and Polyphenol oxidase enzyme activity in some Banana
Cultivars and Hybrids under water stress
K. Krishna Surendar
1
, D. Durga Devi
2
, P. Jeyakumar
3
, K. Velayudham
4
, I. Ravi
5
1. Assistant Professor, Crop Physiology, Regional Research Station, TNAU, Paiyur
2. Professor, Department of Crop Physiology, TNAU, Coimbatore. Tamil Nadu, INDIA
3. Professor & Head, Department of Crop Physiology, TNAU, Coimbatore. Tamil Nadu, INDIA
4. Dean, Agriculture College & Research Institute, TNAU, Madurai. Tamil Nadu, INDIA
5. Principal Scientist, National Research Centre for Banana (ICAR), Thiruchirapalli
Corresponding author email
Genomics and Applied Biology, 2015, Vol.6, No.4 doi: 10.5376/gab.2015.06.0004
Received: 10 Feb., 2015
Accepted: 22 Mar., 2015
Published: 10 Apr., 2015
© 2015 Surendar et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Surendar et al., 2015, Changes in Proline and Polyphenol oxidase enzyme activity in some Banana Cultivars and Hybrids under water stress, Genomics and
Applied Biology, Vol.6, No.4, 1-6
(doi
Abstract
Plant growth and productivity is adversely affected by abiotic stresses induced changes in proline content and polyphenol
oxidase enzyme activity. Field experiments were conducted at the National Research Centre for banana, Thiruchirapalli, during the
growing season of 2011-2013 to compare the changes in proline content and PPO enzyme activity in twelve main crop and ratoon crop
of banana cultivars and hybrids in 5
th
and 7
th
MAP (Month after Planting) under two levels of irrigation. The lowest reduction in the
bunch yield of tolerant banana cultivars and hybrids viz., Karpuravalli, Karpuravalli x PisangJajee, Saba, and Sannachenkathali with
the highest increase in proline and PPO enzyme activity was observed in 5
th
and 7
th
MAP stage due to 50 per cent depletion in available
soil moisture (ASM) of the stress.
Keywords
Water deficit; Proline; Polyphenol oxidase; Yield; Banana
Introduction
In higher plants, proline is a candidate biochemical
solute, being well known as a stress indicator,
especially of water deficit stress. (Yoshiba et al., 1997).
The proline biosynthesis pathway in plant s has been
well established via glutamate intermediate, using
P5CS (∆
1
pyrroline- 5 -carboxylate synthetase) to P5C
(∆
1
-pyrroline-5-carboxylate), subsequently oxidized
to the final product proline by P5CR (∆
1
-pyrroline-
5-carboxylate reductase). Also, proline degradation
has been discovered through ProDH (proline
dehydrogenase) from proline to P5C (∆
1
-pyrroline-5-
carboxylate) and then P5CDH (∆
1
-pyrroline-5-
carboxylatedehydrogenase) (Verslues and Sharma,
2010). The function of proline in plant defence
responses to water deficit stress has been reported,
including signal transduction, osmoregulation and
antioxidant systems (Dalauney and Verma, 1993).
Poly Phenol Oxidase
is a copper-containing enzyme
and is responsible for the enzymatic browning
reaction occurring in many fruits and vegetables. In
the presence of molecular oxygen, PPO catalyzes the
o
-hydroxylation of monophenols to o-diphenols
(monophenolase activity) and oxidation of the
o-diphenols to o-quinones (diphenolase activity)
(Chararra et al., 2001). The synthesis of phenolic
compounds is often enhanced in plant tissues under
oxidative stresses such as drought and mechanical
damage (Reyes and Cisneros-Zevalloss, 2003).
Bananas are quite sensitive to drought; however,
genotypes with “B” genome are more tolerant to
abiotic stresses than those solely based on “A”
genome. In particular, bananas with “ABB” genomes
are more tolerant to drought and other abiotic stresses
than other genotypes (Ravi et al., 2013). Salekdeh et al.
(2009) mentioned that the reduction in banana growth
and yield may be due to the shortage of water in the
root zone.
Drought is one of the important abiotic constraints
restricting banana cultivation and its further adoption
