Photosynthetic Differences among Lycopersicon Species and Triticum aestivum Cultivars

Abstract

Leaf photosynthesis rate (A) and water use efficiency expressed as A/gs (gs, stomatal conductance) are controlled by stomatal properties and leaf internal anatomical and biochemical/physiological characteristics. Two germplasm entries were selected from each of the genera Triticum and Lycopersicon with contrasting drought resistance. Both drought resistant entries (L. pennellii and T. aestivum cv. TAM W‐ 101) had the greater A/gs within each pair. Of the two entries with high A/gs, L. pennellii had lower A and TAM‐101 had higher A than the respective counterpart with low A/gs (L. esculentum and T. aestivum cv. Sturdy, respectively). Comparison of photosynthetic stomatal supply capacities and mesophyll biochemical demand capacities suggested that differences in mean A and A/gs in contrasting tomato species were dependent on the lower mean gs of L. pennellii than L. esculentum, because in leaves with equal gs the balance between stomatal supply and mesophyll demand was identical. In wheat leaves operating at identical gs, however, TAM W‐101 had greater mesophyll capacity than Sturdy. Lower A and A/gs of Sturdy than TAM W‐101 was correlated with lower carboxylation efficiency and lower light and CO2 saturated A, factors associated with the photosynthetic biochemistry of mesophyll tissue. At identical gs, the balance between mesophyll and stomatal capacities and limitations of TAM W‐101 was the same as for the two tomato species. This suggested that for these three entries (L. esculentum, L. pennellii, and TAM W‐101), the differences in A and A/gs resulted from differences in the mean and range of gs. Sturdy was unique by having low A and low A/gs, a result of poor mesophyll capacity compared to the other entries.

Growth and water‐use efficiency of 10 Triticum aestivum cultivars at different water availability in relation to allocation of biomass

“…In wheat, variation in photosynthetic water-use efficiency has been reported to result from differences in photosynthetic capacity or in stomatal conductance (Condon et al 1990;Morgan & LeCain 1991;Martin, Kebede & Rilling 1994). In the present experiment, variation in stomatal conductance rather than in the rate of photosynthesis caused the differences in photosynthetic water-use efficiency, as found previously for eight wheat genotypes by Morgan et al (1993) and for 10 common bean cultivars by Ehleringer (1990).…”

Water Use Efficiency, Transpiration Efficiency, and Uptake Efficiency of Wheat during Drought

“…This confirms the results of Zhang et al (1998) and Stegman et al (1980), who reported that water stress might increase TE. The variation in TE could be interpreted on the basis of photosynthetic capacity and stomatal conductance of the plants (Condon et al, 1990; Martin et al, 1994). Theoretically, more accessible water is conducted to more photosynthetic capacity, and thus, more gas is exchanged in the plants.…”

Physiological and morphological adaptations in relation to water use efficiency in Mediterranean accessions of Solanum lycopersicum

“…3b). A N / g s and δ 13 C values have been reported to be lower in tomato crop cultivars when compared to wild tomato species (Martin & Thorstenson 1988; Martin, Kebede & Rilling 1994; Martin, Tauer & Lin 1999; Comstock et al . 2005; Easlon & Richards 2009).…”

“…3b). tomato species (Martin & Thorstenson 1988;Martin, Kebede & Rilling 1994;Martin, Tauer & Lin 1999;Comstock et al 2005;Easlon & Richards 2009). It is remarkable that AN/gs and d 13 C values for the TR accessions studied here were similar or even higher than those previously reported for wild tomato species.…”