Temperature-dependent growth and emergence of functional leaves: an adaptive mechanism in the seedlings of the western Himalayan plant Podophyllum hexandrum
IR@IHBT: CSIR-Institute of Himalayan Bioresource Technology, Palampur
View Archive Info| Field | Value | |
| Title |
Temperature-dependent growth and emergence of functional
leaves: an adaptive mechanism in the seedlings of the western
Himalayan plant Podophyllum hexandrum
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| Creator |
Kushwaha , R
Pandey , S Chanda , S Bhattacharya , Amita Ahuja, Paramvir Singh |
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| Subject |
Plant sciences
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| Description |
As an adaptive mechanism, hypocotyl dormancy
delays emergence of functional leaf until favorable
season of growth in Podophyllum hexandrum, an endangered
medicinal plant of the western Himalayas. However,
upon exposure of the freshly germinated seedlings to
favorable temperature (25 degree C), functional leaves emerged
within 20 days. Therefore, we examined regulation mechanisms
of growth and development of this alpine plant by
temperature under laboratory conditions. The seedlings
were exposed to (1) 25 degree C (temperature prevailing at the
time of maximum vegetative growth), (2) 4 degree C (mean
temperature at the onset of winter in its natural habitat),
and (3) 10 degree C (an intermediate temperature). Slackened
growth at 4 degree C was followed by senescence of aerial parts
and quiescence of roots and predetermined leaf primordia.
Rapid development of leaf primordia at 25 degree C was associated
with increased starch hydrolysis. This was evident
from higher a-amylase activity and reducing sugars. These
parameters decreased on sudden exposure to 4 degree C. In concontrast,
the roots (perennating organs) showed a slight
increase (1.36-fold) in a-amylase activity. Growth and
development in seedlings growing at 10 degree C(temperature
less adverse than 4 degree C) were comparatively faster. The
content of reducing sugars and a-amylase activity were
also higher in all the seedling parts at 10 degree C as compared to
4 degree C. This indicated larger requirements for sugar by the
seedlings at 10 degree C. Irrespective of temperature, maximum
changes in nitrate and nitrate reductase occurred during the
initial 10 days, i.e., when the readily available form of
sugars (reducing sugar) was highest. This indicated that a
temperature-dependent availability of carbon, but not
temperature itself, was an important regulator of uptake
and reduction of nitrogen.
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| Date |
2008
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://ihbt.csircentral.net/20/1/2008_Temperature.pdf
Kushwaha , R and Pandey , S and Chanda , S and Bhattacharya , Amita and Ahuja, Paramvir Singh (2008) Temperature-dependent growth and emergence of functional leaves: an adaptive mechanism in the seedlings of the western Himalayan plant Podophyllum hexandrum. Journal of Plant Research, 121 (3). pp. 299-309. |
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| Relation |
http://ihbt.csircentral.net/20/
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