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We examined changes in chlorophyll absorbency in red spruce (Picea rubens Sarg.) foliage in response to simulated freezing cycles. Current-year branch tips were collected from 16 trees on January 8, January 20, February 8 and February 26, 1996. Tissue was subjected to freezing cycle treatments with a minimum of -35 degrees C and a maximum of 3 degrees C for a one-cycle treatment, and -9, -6, -3, 0 or 3 degrees C for four-cycle treatments. Samples were frozen at a rate of 5 degrees C h(-1), and warmed at 12 to 15 degrees C h(-1). Controls were held at -9 degrees C. Temperatures during the three-day periods preceding each sample date averaged -18, 4.7, -9.6 and 3.7 degrees C, respectively. On January 8, treated trees showed no significant (P > 0.1) increase in the breakdown of chlorophyll, as measured by the ratio of chlorophyll a absorbency (435 nm) to phaeophytin a absorbency (415 nm), compared with control branch tips. On later sampling dates, seven trees consistently exhibited needle reddening and nine exhibited few symptoms (< 10% of total needle surface reddened) after four-cycle treatments. On February 26, chlorophyll degradation in trees with needle reddening differed (P < 0.05) from the control by 26, 26, 16, 14 and 15% for the 3, 0, -3, -6 and -9 degrees C maxima, respectively. No detectable chlorophyll degradation occurred after a one-cycle treatment in any trees on any sampling date. Freezing cycles with sub-zero maxima and a -35 degrees C minimum enhanced winter injury in red spruce after a midwinter thaw had rendered the trees susceptible to freezing damage.

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Storage experiments were conducted in specially constructed silos each containing 10 kg barley at different moisture contents under controlled conditions at 20"c. BrB-ley at I2 and 14 % moisture stored satisfactorily without mould development during an experimental period of 30 weeks. At increasing moisture contents a good correlation was found between increases in mould growth, COZ production, and contents of reducing sugars, and decreases in non-reducing sugars and in germinative capacity. At the higher moisture contents, temperature rise took place and the feeding quality to rats was impaired.Among the storage moulds Aspergillus was the predominating genus at moisture contents up to about 18 %, while Penicillium spp. were prevalent at higher moisture contents. At the highest moisture content (26%) Fusarium spp. also developed vigorously. After storage, the barley was steeped and sprouted in micromalting equipment; Fusarium and Aspergillus developed more vigorously than in the barley, particzilarly in green malt produced fiom barley with a high moisture content.

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