Agriculture Reference
In-Depth Information
effects of light interception patterns in mango canopies on productivity is
seriously constrained by lack of sufficient quantitative data.
A key enzyme associated with abiotic stress responses of crops,
Rubis-
co
limited rate of photosynthesis is less sensitive to temperature as the
decrease in carboxylation at low temperatures is partially compensated by
suppression of photorespiration.
RUBP
-regeneration limited rate of pho-
tosynthesis, which depends upon much less on oxygenation however, is
fairly sensitive to temperature. Observations at CISH, Lucknow on differ-
ent varieties of regular (
Amrapali, Totapuri
) and biennial (
Langra, Chau-
sa, Dashehari
) during different phenophases which experienced range of
temperatures in 2012-2013,exhibited different levels of sensitivity to low
temperatures for their photochemical reaction (
Personal observation
and
Singh et al., 2012).
Higher amounts of PN with concomitantly high leaf water potential
during periods of rank vegetative growth (March and September-Novem-
ber) coincided with periods characterized by the prevalence of high tem-
peratures and soil moisture and hence they are found vulnerable FBD, a
metabolically highly dynamic stage also maintained high PN levels obvi-
ously indicating high sink activities with correspondingly high leaf water
potential, however a period of stress precludes this phenomenon and under
subtropical conditions, this is provided by cold. This stage could turn out
to be vulnerable, if intervened by heavy rainfall so that the reproductive
primordia could revert to the vegetative one. Such an unfavorable event
logical weeks starting from September, 42-46). Decrease in PN in leaves
during flowering is attributable to the decrease in stomata conductance.
Reduction in this parameter could also be due to differences in the leaf
water state of shoots. Thus it is possible that flowering results due to local
water stress. Increase in PN during fruit set could be attributed to higher
sink activity demanding increased mobilization of photosynthates to the
developing fruit lets. Based on the pattern of flushing, the maximum flush-
es were recorded during March in both the years. However, in 2011 the
significantly higher flush was also recorded during June-August (16.91-
38.26%) in addition to March flushing, which is attributed to relatively
lower intensity of reproductive phase of the previous fruiting season.
