Showing papers by "William B. Miller published in 1993"

Carbohydrates in Alfalfa Seed Developed for Salt Tolerance during Germination

Abstract: Alfalfa (Medicago sativa L.) is an important forage crop in many areas of the world where salinity limits crop productivity. Alfalfa that is salt tolerant during the germination stage has been developed through eight cycles of recurrent selection starting with Mesa-Sirsa. We investigated physiological attributes that may have been affected by selection, recognizing that understanding the basis of tolerance could facilitate more precise techniques for identifying salt-tolerant plants in breeding programs. Free sugars in seed of Mesa-Sirsa and in Cycle 5 and Cycle 8 (C5 and C8) from the selection program were extracted with 95% (v/v) ethanol and the residue hydrolyzed with 4M H 2 SO 4 . All carbohydrates were quantified by HPLC [...]

Reversed Greenhouse Temperatures Alter Carbohydrate Status in Lilium longiflorum Thunb.

Abstract: Commercial greenhouse operators are increasingly using "negative DIF" temperature regimes to control crop height. A negative DIF exists when greenhouse night temperature is greater than the day temperature. Large negative differences in day and night temperatures strongly suppress stem elongation in many crops. We have explored the effects of negative DIF temperature regimes on leaf, flower, and stem carbohydrate levels in Lilium longiflorum Thunb. 'Nellie White'. During two growing seasons, 'Nellie White' plants were grown under positive or negative DIF regimes (±5 or 8C) under prevailing daylengths, with temperatures adjusted so that daily temperature averages were equal between regimes. Plants were harvested ≈10 days after visible bud stage and at anthesis. Carbohydrates in stems, leaves, and flowers were analyzed by high-performa nce liquid chromatography. Compared to plants grown under positive DIF, negative DIF plants showed significantly reduced stem length and leaf and stem dry weights. Negative DIF regimes reduced leaf and stem total soluble carbohydrate (TSC) content by 39% to 46% at visible bud and anthesis, while flower TSC content was reduced by 10% to 13%. Most plants respond to thermoperiodi sm, or the alteration of day and night temperatures. Went's work in the 1940s indicates that most plants show more vigorous growth when the day tem- perature is higher then night temperature (Went, 1944, 1957). This work formed the basis for the common practice of maintaining