Juice tissues of citrus lack phloem; therefore, photosynthates enroute to juice sacs exit the vascular system on the surface of each segment. Areas of extensive phloem unloading and transport (vascular bundles + segment epidermis) can thus be separated from those of assimilate storage Uuice sacs) and adjacent tissues where both processes occur (peel). Sugar composition, dry weight accumulation, and activities of four sucrose-metabolizing enzymes (soluble and cell-wall-bound acid invertase, alkaline invertase, sucrose synthase, and sucrose phosphate synthase) were measured in these transport and sink tissues of grapefruit (Citrus paradisi Macf.) to determine more clearly whether a given enzyme appeared to be more directly associated with assimilate transport versus deposition or utilization. Results were compared at three developmental stages. Activity of sucrose (per gram fresh weight and per milligram protein) extracted from zones of extensive phloem unloading and transport was significantiy greater than from adjacent sink tissues during the stages (II and ll) when juice sacs grow most rapidly. In stage 11 fruit, activity of sucrose synthase also significantly surpassed that of all other sucrose-metabolizing enzymes in extracts from the transport tissues (vascular bundles + segment epidermis). In contrast, sucrose phosphate synthase and alkaline invertase at this stage of growth were the most active enzymes from adjacent,

Soluble sugar composition of developing soybean seed (Glycine max L. Merr.) vary with cultivar. This study was conducted to determine the relation between soluble sugar accumulation and associated enzyme activities in developing seed of two soybean cultivars, Williams 82 and Wolverine. Activities of sucrose synthase, invertase, galactinol synthase, and α‐galactosidase were compared to soluble sugar content (hexoses, galactinol, myo‐inositol, oligosaccharides) at seven different reproductive growth stages. A twofold higher dry matter content in mature seeds of Wolverine corresponded to a larger seed size and longer linear seed fill. Increases in sucrose synthase and alkaline invertase activities in both cultivars corresponded to accumulation of 90% total dry matter. Acid invertase activity remained below 45 nmol glucose seed−1 min−1 during seed development. Initial raffinose and stachyose formation occurred at beginning maturity in Williams 82 and full seed in Wolverine. This change in sugar partitioning during late seed development was accompanied by twofold and threefold increases in galactinol synthase activity and galactinol content, respectively, and a substantial decrease in the substrate for this enzyme, myo‐inositol. Highest levels of galactinol synthase activity at the end of linear seed fill in both cultivars, however, preceded the accumulation of the highest stachyose levels by two growth stages. Activity of α‐galactosidase increased linearly in both varieties with time. Relatively high activities of sucrose synthase and alkaline invertase during the accumulation of the majority of dry matter in both cultivars suggest that these enzymes may be associated with this process in soybean seeds. Regulation of raffinose oligosaccharide accumulation in developing soybean seeds also may depend on galactosyl transferase activity.

Undergraduate minority retention and graduation rates in STEM disciplines is a nationally recognized challenge for workforce growth and diversification. The Benjamin Banneker Scholars Program (BBSP) was a five-year undergraduate study developed to increase minority student retention and graduation rates at an HBCU. The program structure utilized a family model as a vehicle to orient students to the demands of college. Program activities integrated best K-12 practices and workforce skillsets to increase academic preparedness and career readiness. Findings revealed that a familial atmosphere improved academic performance, increased undergraduate research, and generated positive perceptions of faculty mentoring. Retention rates among BBSP participants averaged 88% compared to 39% among non-participant STEM peers. The BBSP graduation rate averaged 93% compared to 20% for non-participants. BBSP participants were more likely to gain employment in a STEM field or enter into a professional study. This paper furthers the body of research on STEM workforce diversity and presents a transferrable model for other institutions.

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