Stem Moisture Content Research Articles

The Relationship of Impedance Ratios and Stem Moisture Content to Vegetative Maturity and Dormancy in Red-osier Dogwood1

Abstract Electrical impedance ratios and water contents were measured during the development of vegetative maturity and dormancy in a clone of red-osier dogwood Cornus sericea L.) on plants exposed to 16 hour and 12 hour photoperiods in growth chambers to selectively prevent or induce dormancy. Vegetative maturity was designated as the point at which buds were no longer stimulated to grow following artificial defoliation. After this time the ratio of impedance values obtained from the frequencies 10 kHz:100kHz increased and tissue water decreased. Electrical impedance ratios were more easily measured and showed less variation between plants. We conclude that electrical impedance ratios are a means of identifying the onset of vegetative maturity and dormancy in woody deciduous species.

The mean accuracy and the precision of using stem disc moisture contents to estimate stem dry weight of Pinus resinosa ait

The moisture content gradient of dominant-codominant red pine stems was examined. The moisture contents of discs removed from five positions on the stem were used to estimate the stem dry weight. Each disc when used alone, does not represent the moisture content of the stem accurately. All discs used together improve the precision of dry weight estimates but not to the degree expected. It is suggested that more than one disc be removed from the stem to adequately estimate the stem moisture content, and stem dry weight.

Preharvest Desiccation of Grain Sorghum with Glyphosate1

AbstractThe need for an effective and nontoxic preharvest desiccant for grain sorghum (Sorghum bicolor (L.) Moench) has been recognized for many years. Studies were conducted to compare glyphosate [(N‐phosphonomethyl) glycine] to sodium chlorate and paraquat (1,1'‐dimethyl‐4,4'‐bipyridinium ion) on hybrids RS 626 and Tophand. Glyphosate was more effective than sodium chlorate or paraquat in reducing grain, leaf, and stem moisture content. Glyphosate reduced grain moisture content to 13% or lower within 1 week after treatment from original grain moisture content of 20, 30 or 40%. Glyphosate prevented growth of axillary buds of grain sorghum and killed all established johnsongrass and Coloradograss in treated agreas. Lodging of grain sorghum was insignificant for 3 weeks following glyphosate treatment, despite heavy rainfall and high wind velocity. Germination of treated grain was not affected by glyphosate at rates of 0.56 and 1.12 kg/ha. The low mammalian toxicity and the absence of phytotoxicity from soil residue suggests that glyphosate may be a valuable preharvest grain sorghum desiccant.

Effect of moisture stress on red maple seedlings from different seed sources

Red maple (Acer rubrum L.) seedlings grown from half-sib seed collected from wet and dry sites were subjected to three levels of plant water stress. Transpiration on a per seedling and per unit leaf weight basis was greatest in seedlings from a swamplike site, at both high and low water potentials. Seedlings from the two wet sites came to temporary and permanent wilt sooner than seedlings from dry sites. However, at all levels of water stress, growth rates were greater for the seedlings from the wet sites than for those from the dry sites. At permanent wilt, the stem and leaf moisture content and the water potential values were highest in the seedlings from the swamplike site. At temporary wilt, the leaf water potential was lowest in seedlings from dry sites. Transpiration of seedlings from a swamplike site was double that of those from another wet site at the same leaf water potential.

Influence of stems in alfalfa forage on the formation of wafers

The influence of alfalfa stems on the formation of wafers in a closed-end die was investigated by varying the stem content of a mixture of alfalfa leaves and stems as well as independently varying the moisture content of the leaves and stems in the mixture. These experiments were conducted with both ground and chopped material. Increased quantities of stems in alfalfa cause a reduction in the density of wafers that are formed. Material with higher stem content had a reduced protein content which reduced the bonding potential. High stem moisture also was detrimental to wafer formation. Material in a combination of low stem content and low stem moisture content produced the densest forage wafer. The quantities and mechanical characteristics of plant stems will seriously influence the quality of forage wafers.