Chlorophyll fluorescence characteristics, performance and survival of freshly lifted and cold stored Douglas fir seedlings

Abstract

-The physiological condition of three-year-old Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] was periodically assessed from October to May 1998/1999 during propagation of seedlings in an Irish nursery. Seedling physiological status was evaluated in situ using determinations of chlorophyll fluorescence and plant water status. Pre-and post-cold stored (either -2 o C or +0.5 o C) plant vitality was examined using determinations of root growth potential (RGP), root electrolyte leakage (REL), shoot water content and chlorophyll fluorescence. Data obtained from freshly lifted and cold stored stock showed that chlorophyll fluorescence provides a reliable (non-destructive) method of evaluating a seedlings potential field performance in both pre-lift (direct planting) and post-storage (outplanting) situations. Variations in survival and an index of plant health were paralleled by inverse changes in the effective quantum yield of photosystem II (Φ PSII) from November to April. Significant positive non-linear relationships were found between RGP and Φ PSII, though they were of limited predictive ability in terms of outplanting performance. Post-storage fluorescence assessments indicated down-regulation and/or damage of the plants photosynthetic light-harvesting complex, which depended on storage temperature and duration. Ann. For. Sci. 58 (2001) [225][226][227][228][229][230][231][232][233][234][235] 225

Sodium silicate mediated response of antioxidative defense system in <em>Lycopersicon esculentum</em> mill. under water stress

“…The chlorophyll stability index is an indicator of the stress tolerance capacity of plants [59].The chlorophyll content decreased to a significant level at higher water deficit condition in sunflower plants [60] and Vaccinium myrtillus [61]. The activity of PSII helps to sustain photosynthesis process in leaves exposed to abiotic stresses and this pigment system is the primary target of damage caused by photoinhibition [62]. Water deficit conditions considerably damage the oxygen evolving complex of PSII and the PSII reaction centers in most of the plants [63].…”

Influence of foliar application of silicon on chlorophyll fluorescence, photosynthetic pigments, and growth in water-stressed wheat cultivars differing in drought tolerance

“…The activity of PSII helps to sustain leaf photosynthesis in plants exposed to abiotic stresses and this pigment system is the primary target of damage caused by photoinhibition (Perks et al, 2001), although some controversies exist concerning this notion (Souza et al, 2004). Addition of inorganic nutrients to the root growing medium of plants subjected to drought stress causes protection of different cellular organelles (Aiken, 1996).…”

Interactive effects of irradiance and water availability on the photosynthetic performance of Picea sitchensis seedlings: implications for seedling establishment under different management practices

“…The pre-treatment and physiological status of seedlings selected from the nursery may influence the performance of transplants in this study and under field conditions [24]. The extent to which this occurs may vary depending on nursery silvicultural procedures.…”

“…The impact of water deficits could also be exacerbated due to the out-planting of bare-root seedling stock, as is used in Ireland and the UK, in the early spring [24]. The shallow rooting pattern of Sitka spruce in wet mineral soils [22] may render seedlings more susceptible to transient water deficits that are typically experienced between April and July [21].…”