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6980969 
Journal Article 
Differential response of two wheat genotypes to nitrogen supply. II. Mesophyll cell characteristics and photosynthesis of laminae at full expansion 
Sivasankar, A; Lakkineni, KC; Jain, V; Kumar, PA; Abrol, YP; , 
1998 
1 
Journal of Agronomy and Crop Science
ISSN: 0931-2250
EISSN: 1439-037X 
BLACKWELL WISSENSCHAFTS-VERLAG GMBH 
BERLIN 
65-70 
WOS:000075512200001 
Two wheat genotypes, viz. Uniculm 'Gigas' (IV) and Kalyansona (V2) were raised to maturity under two levels of nitrogen supply @ 30 (N1) and 120 (N2) kg ha(-1), under pot culture conditions. Laminae numbering 1 to 8 on the shoot were examined for area, net photosynthetic rate (P-n) and mesophyll cell characteristics, at full expansion. N1 resulted in greater reduction in the area of upper laminae in V1 than in V2. The flag and penultimate laminae maintained similar P-n rates at both N levels in V1 despite a large reduction in area at NI. However, V2 exhibited about 25 % reduction in P-n rates of the flag laminae at N1 as compared with N2. Mesophyll cell number per unit area gradually increased with laminae order in the genotypes. The greater number of mesophyll cells in the upper laminae was essentially due to a reduction in cell size and surface area as a result of low N availability. The large differences in laminae size due to N treatments, particularly in V1, are attributed to mesophyll cell numbers. However, the maintenance of P-n rates in V1, even at low N supply, is a possible outcome of higher activity of the mesophyll cell constituents in this genotype.