Assessment of photosynthetic activity of nursery-grown Piceaglauca seedlings using an integrating fluorometer to monitor variable chlorophyll fluorescence

Abstract

Photosynthetic activity of intact nursery-grown white spruce (Piceaglauca (Moench) Voss) seedlings was assessed by measuring CO2 exchange (apparent photosynthesis) and normalized, integrated variable chlorophyll fluorescence emission. Agreement between fluorescence and apparent photosynthesis indicated that photosynthetic inactivation of seedlings from selected seedlots began in mid-August and approached completion in late October. Inactivation occurred somewhat earlier in northern seedlot seedlings than in those from a more southerly provenance. Seedlings tested in late October showed significant photosynthetic inactivation, as indicated by both fluorescence and apparent photosynthesis. These seedlings also had passed the −18 °C frost hardiness test currently used in British Columbia as an indicator for safe lifting. On removal from −2 °C storage, seedlings lifted and stored according to nursery practises showed fluorescence emission indicative of photosynthetic reactivation and also had high root growth capacity scores. Low root growth capacity scores were associated with delayed or incomplete photosynthetic reactivation. These results show that fluorescence assessment provides information about the physiological status of white spruce seedlings. Variable fluorescence assays are nondestructive and can be made and interpreted within minutes. As an indicator of shoot metabolic activity, fluorescence assessment provides information useful in selecting lifting dates and in evaluating the effects of dark cold storage on white spruce seedlings.

Gas exchange and chlorophyll fluorescence responses of Pinus radiata D. Don seedlings during and after several storage regimes and their effects on post-planting survival

“…A decline in F v /F m is a good indicator of photoinhibitory damage caused by light when plants are subjected to a wide range of environmental stresses, including chilling (Baker et al 1983), freezing (Strand and Öquist 1985) and drought (Ögren and Öquist 1985;Mena-Petite et al 2000), so that the stress caused by storage also alters this ratio (Fig. If after transplanting the fluorescence parameters do not recovery it could be considered an indication of reduced seedling vigour (Vidaver et al 1989) and it could put in risk the post-planting survival (Fig. Thus, the increase of the needle electrolyte leakage, indicative of disruption of membranes, will be responsible for the decrease in the photochemical efficiency (Fig.…”

Effect of four levels of shade on survival, morphology and chlorophyll fluorescence of Nothofagus alessandrii container-grown seedlings

“…Chlorophyll fluorescence has been increasingly used to understand both the mechanism of photosynthesis and the factors affecting it. Vidaver et al (1989) suggested that chlorophyll fluorescence can rapidly provide useful information about photosynthetic responses to environmental stresses.…”

“…Chlorophyll fluorescence has been increasingly used to understand both the mechanism of photosynthesis and the factors affecting it. Vidaver et al (1989) suggested that chlorophyll fluorescence can rapidly provide useful information about photosynthetic responses to environmental stresses.The objective of this study was to evaluate the effects of three different shade levels and unshaded conditions on the survival, morphology, and chlorophyll fluorescence of N. alessandrii seedlings cultivated in containers. The study assessed the hypothesis that N. alessandrii seedlings require some degree of protection from direct sunlight in their early stages of development.…”

Relationships between frost hardiness, root growth potential, and photosynthesis of nursery-grown white spruce seedlings

“…Autumn frosts may significantly decrease leaf or needle area, thus negatively affecting the seedling's photosynthetic capacity and its ability to initiate new roots. During hardening, the photosynthetic apparatus of coniferous species gradually adapts to decreasing temperatures (Öquist and Huner 2003;Vidaver et al 1989). A decrease in photosynthesis or the mass of photosynthetically active foliage as a result of early frost may reduce root initiation and growth, therefore compromising root plug cohesion.…”