Growth and Physiological Response of Fraser Fir [Abies fraseri (Pursh) Poke] Seedlings to Water Stress: Seasonal and Diurnal Variations in Photosynthetic Pigments and Carbohydrate Concentration
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Dosyalar
Tarih
2012
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Amer Soc Horticultural Science
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Four-year-old seedlings of Abies fraseri [(Pursh) Poir] (fraser fir) were grown in semicontrolled conditions in hoop houses with five watering regimes (0.00, 0.62, 1.25, 2.50, and 3.70 cm/week) with the goal of determining the seasonal variation in the physiological response to drought stress. Drought stress was monitored by measuring predawn (Psi pd) and midday (Psi md) potentials in a subset of plants from each treatment. Physiological variables monitored were chlorophyll fluorescence (F-v/F-m), ChI a, ChI b, total carotenes, and total carbohydrate concentrations. Morphological characteristics including height growth, root collar diameter, and terminal shoot growth were also measured. Predawn stem water potential values were generally higher (-0.8 to 1.9 Mpa) than midday values (-1.3 to 2.9 Mpa). Irrigation consistently increased Psi pd and Psi md compared with non-irrigated treatments. Photosynthetic pigments (ChI a, ChI b, and carotenes) decreased midseason (14 July) and increased toward the end of the season (25 Aug.) in predawn and midday measurements. There was a significant effect (P < 0.05) of drought stress on photosynthetic pigment concentrations in predawn and midday samples in the late-season measurements (25 Aug.). These results were accompanied with a similar significant difference in F-v/F-m between non-irrigated and irrigated trees. We concluded that significant effects observed on photosynthetic pigment concentrations in some of the treatments did not affect carbohydrate concentrations. Exposure of A. fraseri to water stress did not cause a reduction in supply of metabolic carbohydrates; consequently, the decline and mortality in water-stressed plants can only be the result of hydraulic failure caused by xylem cavitation leading to cessation of water flow in tissues, desiccation, and cellular death. Further studies are needed to confirm these preliminary conclusions.
Açıklama
WOS: 000310410200023
Anahtar Kelimeler
carotenes, chlorophyll pigments, drought, photosynthesis, total chlorophyll, D-glucose, stem water potential
Kaynak
Hortscience
WoS Q Değeri
Q2
Scopus Q Değeri
Cilt
47
Sayı
10
