Indian J. Plant physiol., Vol. xxXI. No.4. pp. 423-427 (December. 1988)
SHORT COMMUNICATION
PHYSIOLOGICAL STUDIES IN CHICKPEA (CICER A.RlETINUM L.) UNDER QUANTIFIED MOISTURE LEVELS
M.S. KUBAD, B.S. KUNDU,· R.S. HOODA AND I.S. SBEORAN
Department of Botany, Haryana Agricultural University, IDsar-125004
(Received, March 14, J988)
The experiments were conducted in pots to study the pattern of physiological processess like photosynthesis, respiration, nitrogen fixation, water potential. growth and yield at 80% (control), 50% and 30% of soil saturation level in chickpea. At 50% of soil saturation no significant decrease in water potential of Jeaf, root and nodule and photosynthesis, respiration and nitrogenase activity was observed over control at flowering stage. However, these parameters showed a sharp decrease with increase in age of the plant from flowering to grain filling. Reduction was observed in dry weight of leaf, stem. root, nodules and Jeaf area both at 50% and 30% of soil s'lturalion levels and in the two sampling stages, except in dry weight of roots and . nodules which showed enhancement over control at flowering under 50% leve1, which subsequently declined at grain filling stage. The reduction in growth parameters were also reflected in number of pods, dry weigbt of pods and grain yield, but significant decrease was found only at 30% of soil saturation.
Chickpea (Cicer arietinum L.) is a potential cash crop for the dry land area. It is widely grown under poor fertility and scanty rainfall in the arid and semi-arid zone of India and is characterized as drought toleraat but poor yielder. ' Generally, the crop experiences drought during flowering and pod filling stages both because of decreased soil moisture as well as increased atmospheric temperature. Little work hasbeen done on the effect of soil moistue on different physiological processess in this crop (Sheoran and Kubad, 1987). Keeping this in view the present investigation was carried out to find out the critical level of soil moisture which is sufficient to maintain the various physiological processes at a level which does not result in any significant decrease in yield.
The seeds of chickpea (Cicer arietinum L.) var. C-235 were inoculated with effective Q.hizobium culture and sown in pots filled with dune sand of required moisture level i.e. 80% (control), 50% and 30% of soil saturation (soil water content equivalent to 10%, 5.6% and 3.7% respectively). To avoid the evaporation losses, the pots
424
M.S. KtmAD et aiwere covered with polythene sheets. From each treatment, ten pots were weighed daily and the depleted amount of water by surface evaporation and transpiration were replenished. Mter thinning, three plants per pot were retained.
At each sampling (flowering and grain filling stage) photosynthesis and respira tion of whole plant was recorded using Infra Red Gas Analyser as described earher (Luthra et al., 1983). Fourth leaf from top was taken for leaf water potential measurement. At the same time, plants were uprooted and. separated into shoot and root. The root nodules were taken for water potential measurement with pressure .;:hamber and psychrometer respectively as described earlier (Sheoran and Kuhad, 1987). Nitrogen fixation of nodules was measured by acetylene reduction assay of Hardy et 01 (1968) using Gas Chromatograph. Leaf area was recorded with automatic leaf area meter (Li-3000). Dry weight of different plant parts at both the sampling stages and final yield at maturity were also recorded.
Water stress resulted in decreased water potential of leaf, nodule and root at flowering (Table I). The magnitude of decrease in water potential of leaf was more than nodule and root. The significant decrease in water potential was observed only at 30% of soil saturation as compared to control. Roots always maintained higher water potential than nodule and leaf irrespective of the moisture level. Decrease in water potential in different plant parts with decrease in soil moisture has generally been reported (Turner and Kramer, 1980).
Nitrogenase activity and photosynthesis have been reported to be more sensitive parameters to waters stress as compared to respiration (Sheoran and Kuhad, 1987). Decreased water potential at 50% and 30% of soil saturation was accompanied by decrease in photosynthesis at both the stages i.e. flowering and grain filling (Table I).
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SOIL MOlSTlJRE LEVELS ON CHICKPEA
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Table I. Effect of quantified moisture levels on photosynthesis, respiration,
ni~rogenase activity and water potential at two different growth stages.
Photosynthesis Respiration Nitrogenase
(mg COB dm- s (mg COl! g dry wt-1 h-l) activity
h~l) - - - (p. M CaH. g Leaf Nodules Root flesh wt-1 h-1)
- - - - -
---_.-
-
- - -
Stress level I II I II I II I II I II
Control 25.6 22.1 18.5 11.5 13.5 (0.92) (0.66)
12.4 2.6 (0.35)
2.5 4.41 1.14
50% or soil saturation
24.4 21.4 16.7 9.7 10.9 (1.18) (0.78)
6.1 1.6 (0.43)
2.4 4.91 0.98
30% or soil saturation
19.5 13.6 13.8 6.9 8.1 (1.30) (1.05)
5.9 1.0 (0.47)
1.1 3.08 0.94
C.D. at S% 4.09 1.25 3.33 1.36 2.9 (0.27) (0.17)
1.93 0.51 (0.11)
NS NS NS
I
*
Flowering stage II. Grain filling stage(Values in paranthesis are water potential in -MPa)
under continuous moisture stress as compared to the short duration stress. This is clear from the water potential data which decreased only upto -1.3 MPa in leaves and -1.05 MPa in nodules (Table I). Further, probably the substrate available from photosynthesis at 30% of soil saturation might be sufficient to maintain the nitrogenase activity without exhibiting any adverse effect. In addition to photosyn thesis and nitrogenase activity, respiration rate was recorded in leaf, nodule and
root at flowering and grain filling stage under different soil moisture levels (Table I). Leaf maintained higher respiration rates as compared to nodule and root. Moreover, roots maintained the lowest respiration rates. The significant decrease in respiration rate was also observed at 30% of soil saturation.
426
M.S. KUBAD etat
of soil saturation and became higher at grain filling ~tage. Different yield parameters like number of pods, dry weight of pods and grain yield per plant recorded at maturity showed significant decrease at 30% of soil saturation, while at 50% of soil saturation there was no significant difference (Table II). It may be concluded from this study that soH moisture level at
50%
of soil saturation is good for raising· chickpea plants in dune sand.Table
II.
Effect of quantified moisture levels on plant growth and yield characteris ticsPercent reduction in growth parameters
Leaf area Leaf dry Stem dry Root dry Nodule dry
SI ress level weight weight weight weight
50% of soil saturation
30% of soil saturation
50% of soil saturation
30% of soil saturation
Control 50% of soil saturation
30% of soil 8:lturation
C.D. at 5%
12.5
31.9
37.4
60.2
No. of podsI
plant
26.8
25.6
9.0
4.49
Flowering stage
17.4 21.9 24.6 11.3
54.5 45.6
Grain filling stage
13.2 59.1
51.0 14.5 32.8 46.3
67.8 52.0 77.5 46.3
Yield characteristics
Dry weight of pods/plant
4.84
Grain yield/ plant
3.82
4.61 3.67
1.72
0.64
1.61
0.38
REFERENCES
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SOIL MOISTURE LEVELS ON CHICKPEA
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Hooda, R.S. (1987). Partitioning and utilization of photosynthate for dry matter production and nitrogen-fixation under water stress in chickpea (Cker arietinum L.). Ph,D. thesis, Haryana Agricultural University, Hisar, India.
Jones. H.O. and Rawson. H.M. (1979). Influence of rate of development of leaf water deficits up on photosynthesis. leaf conductance. water use efficiency and osmotic potential in sorghum. PhysioJ. Plant .• 45 : 103-111.
Luthra, Y.P., Sheoran. I.S. and Singh. R. (1983). Ontogenetic interactions between photosynthesis and nitrogen-fixation in pigeonpea. Ann. Appl. BioI., 130: 549-556.
Sheoran, I.S. and Kuhad, M.S. (1987). Effect of decreasing soil moisture on photosynthesis, respiration. nitrogen fixation and water relations in gram (Cieer arietinum L.) Proceed ings National Seminar on New Dimention in Pulse Research and Development JNKVV, Jabalpur. In Press.
