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Effects of light regime on δ 13 C, photosynthesis and yield of field‐grown banana ( Musa sp., Musaceae) *
Author(s) -
ISRAELI Y.,
SCHWARTZ A.,
PLAUT Z.,
YAKIR D.
Publication year - 1996
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1996.tb00244.x
Subject(s) - irradiance , photosynthesis , transpiration , musaceae , canopy , horticulture , yield (engineering) , photosynthetically active radiation , productivity , botany , atmospheric sciences , biomass (ecology) , environmental science , stomatal conductance , biology , agronomy , physics , optics , macroeconomics , economics , thermodynamics
Banana plants ( Musa sp., Musaceae) were grown for 2 years in the field in 12×20m plots under irradiance levels incident upon the canopy of 100, 81, 62 and 32% of sunlight. Time‐integrated parameters such as leaf δ 13 C, yield and leaf mass to area ratio were linearly correlated with irradiance level ( R 2 >0.9). In contrast, midday CO 2 assimilation and transpiration efficiency ( A/g ) decreased significantly and substomatal CO 2 concentrations ( c st ) increased significantly only at the lowest irradiance levels (below 81% irradiance). Diurnal gas exchange measurements indicated that the linear response of the long‐term parameters may be associated with the significant variations in photosynthetic activity among the irradiance treatments observed only in the early morning hours. The linear fit between yield and irradiance level (per cent of control) had a slope of 0.82 (with apparently constant yield to biomass ratio). These results directly demonstrate the significance of variations in incident light, such as may be associated with increasing cloudiness, on productivity of tropical plants such as the banana. The importance of using time‐integrated indicators in general, and the reliability of using 13 C discrimination in particular, in evaluating the responses of plants to changes in incident irradiance is demonstrated.