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Photosynthetic Differences among Lycopersicon Species and Triticum aestivum Cultivars
Author(s) -
Martin Bjorn,
Kebede Hirut,
Rilling Christel
Publication year - 1994
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1994.0011183x003400010020x
Subject(s) - lycopersicon , biology , photosynthesis , stomatal conductance , germplasm , botany , cultivar , horticulture
Leaf photosynthesis rate (A) and water use efficiency expressed as A/g s (g s , 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/g s within each pair. Of the two entries with high A/g s , L. pennellii had lower A and TAM‐101 had higher A than the respective counterpart with low A/g s ( 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/g s in contrasting tomato species were dependent on the lower mean g s of L. pennellii than L. esculentum , because in leaves with equal g s the balance between stomatal supply and mesophyll demand was identical. In wheat leaves operating at identical g s , however, TAM W‐101 had greater mesophyll capacity than Sturdy. Lower A and A/g s of Sturdy than TAM W‐101 was correlated with lower carboxylation efficiency and lower light and CO 2 saturated A, factors associated with the photosynthetic biochemistry of mesophyll tissue. At identical g s , 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/g s resulted from differences in the mean and range of g s . Sturdy was unique by having low A and low A/g s , a result of poor mesophyll capacity compared to the other entries.