Publications by G. Lambany

Growth, physiology, and leachate losses in Picea glauca seedings (1+0) grown in air-slit containers under different irrigation regimes

Tue, 19 Mar 2002

In production tunnels, time domain reflectometry (TDR) was used to manage irrigation and leaching by controlling water content in the rhizosphere of air-slit containerized white spruce (Picea glauca (Moench) Voss) seedlings (1+0). Seedlings were exposed to four irrigation regimes (v/v: IR-60%, IR-45%, IR-30%, and IR-15%) during the first growing season to assess IR effects on growth, gas exchange, nutrient uptake, carbohydrates, root architecture, and leaching. In the province of Quebec, seedling producers generally maintain a high substrate water content (>50%, v/v) during all growth phases. The accuracy and feasibility of using TDR to decrease irrigation without affecting the material attributes of the seedlings at the end of the first growing season was confirmed. However, seedlings grown under IR-15% had significantly lower height, root collar diameter, shoot and root dry masses, root surface, root length, net photosynthesis, and nutrient contents than seedlings grown under IR-30%, IR-45%, and IR-60%. In comparison with IR-30% and IR-45%, the application of IR-60% produced no increase in shoot or root growth, mineral nutrition, and carbohydrates. Seedlings grown under IR-15%, IR-30%, and IR-45% used approximately 28, 37, and 46%, respectively, of the amount of water applied under IR-60%. Nutrient losses including anions and cations under IR-60% were higher in comparison with the other IRs. Maintaining a water content in the rhizosphere that changes with the stage of seedling development is suggested to optimize growth and to avoid excess irrigation and leaching.

Relating carbohydrate concentrations to photosynthetic rates and growth in Picea mariana seedlings.

Fri, 18 May 2012

Carbohydrate concentrations of soluble sugars (glucose, fructose, sucrose, raffinose, trehalose), polyols (pinitol, mannitol, sequoyitol, inositol), organic acids (shikimic and quinic acids) and unknown sugars were determined on containerized black spruce Picea mariana [Mill.] B.S.P.) seedlings of three different types (small, medium, and large), planted in raised sand beds maintained under wet, moderately dry or dry soil moisture conditions, three occasions during the growing season. Concurrent measurements of net photosynthesis (P_n) and of relative growth rates (RGR) had shown specific differences and similarities among the three seedling types. Of all the carbohydrates measured, only quinic acid showed patterns of variation that paralleled those observed for P_n and RGR. Large concentrations of quinic acid were associated with seedling types with the highest measured P_n and RGR. No such similarity was observed with any of the other carbohydrates measured. Results suggest that quinic acid concentrations reflect current growth in the seedlings, and are largely independent of interconversions and storage processes that prevent the used of other major carbohydrates as indicators of seedling quality.

Concentrations en glucides chez les plants de fortes dimensions de Picea mariana en réponse au régime hydrique (résumé)

Tue, 22 Aug 2000

Étude comparative de la réponse morphologique et physiologique de plants produits en récipients conventionnels et à parois ajourées

Tue, 22 Aug 2000