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Diagnostic parameters for selecting against novel spruce ( Picea abies ) decline: II. Response of photosynthesis and transpiration to acute NO x exposures
Author(s) -
Saxe Henrik,
Murali N. S.
Publication year - 1989
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1989.tb06202.x
Subject(s) - transpiration , picea abies , photosynthesis , botany , horticulture , biology , growing season , karst , stomatal conductance , respiration , paleontology
The dose‐ and time‐response effects of sequential 3 h+3 h NO→NO 2 day time exposures [0–9 μl l −1 (ppm) NO, 0–7.5 μl l −1 NO 2 ] followed by 3 h+3 h NO→NO 2 night‐time exposures (0–9.5 μl l −1 NO, 0–9 μl l −1 NO 2 ) on photosynthesis, transpiration and dark respiration were examined for nine Carpatho‐Ukrainian (‘Rachovo’) half‐sib families and for two populations, one from the FRG (‘Westerhof’) and one from the GDR (‘Schmiedefeld’) of Norway spruce [ Picea abies (L.) Karst.], all in their 4th growing season. In a second exposure series the exposure sequence was reversed. None of the treatments induced needle scorching. The higher NO x (NO or NO 2 ) concentrations reduced photosynthesis and transpiration within 1 h. The physiology of the different spruce types was affected significantly differently, the most sensitive spruce having its photosynthesis suppressed 6.6 times and its transpiration 5.5 times more than the most tolerant. ‘Westerhof’ was more sensitive to NO 2 than the average ‘Rachovo’ half‐sibs. The gradients of different photosynthesis and transpiration sensitivities among the half‐sibs (and ‘Westerhof’) demonstrated a significant, positive, mutual correlation, but significant negative correlations with the gradient of novel decline symptoms among their parents growing in Danish forests. The relative photosynthesis and transpiration sensitivies may thus serve as diagnostic parameters for laboratory selection of the most resistant trees to novel spruce decline. The average NO 2 flux density was three times larger than the average NO flux density. Only for NO 2 and in light was stomatal NO x uptake larger than the total NO x uptake. Both night transpiration and dark respiration were stimulated by high concentrations of night NO x , preceded by day NO x exposures.