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J. Scott Cameron

The criminal justice system is served by many experts who provide special assistance to law enforcement professionals during criminal investigations. One of these specialized areas. forensic botany, has traditionally been an activity of the systematic botanist who identifies plant material associated with a suspect or crime scene. From this Information, suspects can be placed at crime scenes and information such as time of death or movement of victims can be determined. Few plant scientists are involved In this emerging field which has the potential to make contributions similar to those made today by forensic anthropology.

Plant scientists with training In systematic botany, plant anatomy, plant growth and development, and statistics and probability can make significant contributions to criminal investigations. The use of plant identification and plant growth analyses In recent criminal Investigations will be described. The role of horticulture in the future of forensic science and the development of new techniques In forensic plant science will also be discussed.

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Ann Marie VanDerZanden and J. Scott Cameron

Fragaria chiloensis (Linnaeus) Is a viable. low maintenance alternative to groundcovers currently available in the ornamental landscape industry. There is considerable genetic variability within this specks for leaf morphology, growth and flowering habits as well as drought tolerance. Clones collected from 11 coastal sites in CA and OR were compared for drought tolerance after two Imposed water stress\recovery cycles. Predawn water potential, gas exchange, chlorophyll (chl) content, fourth derivative spectroscopy, carbon isotope discrimination, and total biomass production were evaluated and significant clonal differences were observed.

Predawn water potentials after the first stress cycle ranged from -35.0 MPa to -6.5 MPa. Clones I05, DNT and G19 had highest predawn water potentials and gas exchange rates after both stress cycles. In the control group, I05 and DNT had higher levels of chl a, chl b, total chl and chl a\b. After the first stress cycle, clones DNT and I05 had the highest chl a\b ratio, however, after the second stress event there were no differences In any chl parameters. Varying adaptive abilities observed may suggest differential use in the landscape.

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J. Scott Cameron and Peter R. Bristow

Gas exchange measurements were made on healthy and rose bloom infected branches of cranberry on 31 May 1991 during the middle of the sporing period. CO2 assimilation rates of infected branches were reduced 89% on a leaf area basis and 95% on a dry weight basis compared to healthy tissue. Stomatal conductance was 12× higher in infected tissue, while mesophyll conductance was reduced by 92%. Transpiration was 4× higher in diseased tissue reducing water use efficiency by 96%.

Total chlorophyll content of diseased tissue was 81% less than that of healthy tissue but chlorophyll a/b was unchanged. Fourth derivative profiles of chlorophyll action spectra were altered in diseased tissue. Rose bloom leaves were found to lack stomata and have no discernable mesophyll layer.

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Bruce D. Kelley and J. Scott Cameron

Several anatomical and physiological parameters were measured in 32 genotypes of fragaia, including the cultivated strawberry (frapria × ananassa) and its progenitor speck F. chiloensis and F. virginiana Measurements were made using potted. runner-propagated, &month-old greenhouse-grown plants growing under long day (14/10) conditions.

Significant differences in CO2 assimilation rates (leaf area and dry weight bases). leaf chlorophyll content, leaf soluble protein content, and leaf anatomy were found between subspecies of F. virginana as well as among species. Recessed stomata and greater water use efficiency were observed in F. virginana ssp glauca as well as in F. chiloensis genotypes. In addition, it appears that leaf anatomy characteristics, as studied using light microscopy, may he useful in corroborating taxonomic decisions based upon gross morphology in Fragaria.

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J. Scott Cameron and Carol A. Hartley

Twenty-five female clones of Fragaria chiloensis (L.) Duchesene collected from the California and Oregon coasts were surveyed for gas exchange rates under field conditions. Carbon assimilation (A) rates of native clones were 25% to 69% higher than for `Totem' (Fragaria × ananassa Duchesne) on a leaf-area basis (μmol of CO2 per sec/m2) and 7% to 77% higher when expressed on a leaf dry-weight basis (μmol of CO2 per kg dry wt/sec). Higher rates of stomatal conductance (gs) were observed in 16 of 25 F. chiloensis clones than in `Totem', with nine of 25 clones also having higher rates of transpiration (E). All clones had higher rates of residual conductance (gr) and greater water use efficiency (WUE) than the cultivated standard. The gas exchange characteristics of four strawberry cultivars (F. × ananassa) and four F. chiloensis genotypes were compared under standard greenhouse conditions. F. chiloensis genotypes had higher rates of A than cultivars when expressed on per leaf-area and dry-weight bases. Native clones also had higher rates of gs, gr, E, and WUE and greater quantum yield. Differences in chlorophyll content were observed among genotypes, but not between species.

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Chuhe Chen, J. Scott Cameron, and Stephen F. Klauer

Accumulated attendance and fourth-derivative spectra were measured using intact leaf samples at mom temperature for 80 genotypes of four Fragaria species. Attendance peak wavelength and amplitude data of all samples was pooled and yielded 25 common bands for Fragaria. Of these, 14 chlorophyll bands and two phototransformed bands were consistent with French's (1972) model.

Peak wavelengths and amplitudes which represent major bands in F. chiloensis and F. × ananassa spectra were also determined separately. While peak wavelengths of the two species were identical, variation was noted in peak amplitude. The signals of the bands at Cb640, Cb649, Ca670, Ca673, Ca675-676, Ca684 and Ca693 in F. chiloensis were significantly stronger than those in F. × ananassa. Ca677 and Ca695 were stronger in F. × ananassa.

The greatest difference among Fragaria species was found in the amplitude of Ca693. The amplitude of this peak was greatest in F. chi/oensis (0.0025) and smallest in F. virginiana (-0.0005), The cultivated hybrid of these two species, F. × ananassa, was intermediate (0.0008), Preliminary evidence suggests that certain genotype-specific spectral characteristics may relate directly to observed differences in photosynthetic biology among these species.

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Chuhe Chen, J. Scott Cameron, and Ann Marie VanDerZanden

Leaf water potential (LWP). relative water content (RWC), gas exchange rates and 4th-derivative spectra were measured in water-stressed and normally Irrigated plank of Totem' strawberry (Fragaria × ananassa) grown in a growth chamber. CO2 assimilation rate (A) dropped sharply when LWP decreased from -0.5 to -1.2 MPa and almost ceased as LWP fell below -1.5 MPa. There was a significant but more gradual decline of A as RWC decreased form 90% to 55%. An exponential relationship with A was observed across a wide range of LWP and RWC (Rz= 0.64, 0.86, respectively). LWP was more closely related with transpiration and leaf and stomatal conductances than with A and water use efficiency. RWC was highly correlated with all gas exchange parameters.

Under moderate water stress, younger leaves maintain higher RWC and A than older leaves. There was no relationship between LWP and leaf age.

RWC and A were both negatively correlated with peak amplitudes of Ca 684 and Ca 697 and positively correlated with Ca 693 in their 4th-derivative spectra of chlorophyll. LWP had a negative correlation with Cb 640.

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Paul W. Foote, J. Scott Cameron, and Stephen F. Klauer

Leaf-area based CO2 assimilation rate (ALA as an Indicator of genotypic differences in photosynthetic capacity is questioned on the basis of correlations found between ALA and specific leaf weight and small leaf size. To address this question of photosynthetic apparatus concentration In F. chiloensis genotypes differing significantly in ALA, visual image analysis software was used to quantify a number of leaf anatomy parameters. In 1991 and 1992, after gas exchange measurements in the field, leaf tissue was prepared In cross-sections and leaf clearings for light microscopy. Cross-sections were used to measure internal anatomical parameters and clearings for vein and stomatal densities.

Analysis of variance of 1991\92 measurements showed significant genotypic variation for leaf veination, leaf thickness, palisade cell length, cross-sectional area In mesophyll tissue and internal air space. Differences in stomatal density were observed in 1991. None of the anatomical parameters measured were correlated with ALA. This suggests that the concentration of physical apparatus Is not the major source of variation In ALA among these eight genotypes.

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Stenhen F. Klauer, J. Scott Cameron, and Paul W. Foote

Results from previous cultural and physiological studies of red raspberry suggest that primocanes compete with floricanes for light, nutrients and/or photoassimilates. This study was undertaken to determine whether this competition might be reflected in the actual translocation of photoassimilates between the two types of canes. In 1993, pairs of greenhouse grown, potted red raspberry (Rubus idaeus L.) plants contaming one or two floricanes and numerous primocanes were labeled with 14CO2 on four dates corresponding with early anthesis, green fruit, red fruit and post fruit maturity stages of the growing season. For each experiment, either a floricane or a primocane was exposed to 92.5μCi 14CO2 within a sealed bag. After 24 hours, the bag was removed and the presence of label was monitored for up to 11 days. Activity was determined using liquid scintillation. At all developmental stages 14C moved from the labeled floricane to primocanes that were from 2.5 cm to 1.5 m tall and to the roots. Movement was quickest and relatively greatest at early anthesis, dccreascd during fruiting, and was still occuring at 2 months after fruit maturity. Small amounts of label were detected in roots of labeled primocanes at all stages, but trace amounts were present in fruit and other primocanes only at post fruit maturity.

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Stephen F. Klauer, Chuhe Chen, and J. Scott Cameron

In 1999, yield of the split (ST) vs. conventional trellis (CT) was again compared in “Meeker” red raspberry. Field-testing was repeated at four sites in north (Lynden) and southwest (Woodland, Ridgefield, WSUV REU) Wash. A variety of widths, crossarm styles, and machine harvesters were tested in fields with varied cultural practices. Topped and tied-over canes were compared at two locations. In previous years, estimated yield potentials have been 20% to 60% greater for ST, but actual yields have only been 10% to 13% greater because of harvester damage to laterals and premature pick of green fruit. This year, Littau Harvester suggested minor machine adjustments that addressed these problems, resulting in a 19.4% yield increase for a 51-cm ST (Lynden). Lateral damage was minimized by spreading the picking heads to begin harvest, and then moving them closer after every three harvests. Excessive green fruit was controlled by reducing beater rod speed. A rough cost/benefit analysis indicates that there would be substantial economic gain (15% more $/acre in this case, assuming $0.50/lb fruit) for ST vs CT at this level of yield increase. There was no difference in harvest efficiency between treatments at WSUV. More fruit was lost to drop in the row center for ST in Lynden. Topped canes in CT and ST had reduced yields of 11 and 19% respectively compared to their tied-over counterparts. Topped ST canes had 11% greater yield than topped CT canes. ST canopies were larger, and had more leaves than CT. No differences were seen on a leaf-area basis between treatments for leaf: CO2 assimilation, fluorescence, and chlorophyll or in primocane leaf total nitrogen. Increased ST yields were recorded for a 2nd year at two locations, which supports yield sustainability for ST.