Inheritance profile of weathered chlordane and p,p'-DDTs accumulation by Cucurbita pepo hybrids.

Cucurbita pepo ssp pepo (zucchini) accumulates significant levels of persistent organic pollutants in its roots, followed by unexpectedly high contaminant translocation to the stems. Most other plant species, including the closely related C. pepo ssp ovifera (squash), do not have this ability.

Accumulation of weathered p,p'-DDTs in hybridized Cucurbita pepo cultivars.

Cucurbita pepo spp pepo (zucchini) is known as an exceptional weathered dichlorodiphenyldichloroethylene (DDE) accumulator, whereas Cucurbita pepo ssp ovifera (squash) is termed a nonaccumulator. Experiments were conducted with hybridized zucchini and squash to assess the inheritance pattern of DDX (the sum of p,p'-dichlorodiphenyltrichloroethane [p,p'-DDT], p,p'-dichlorodiphenyldichloroethane [p,p'-DDD], and p,p'-dichlorodiphenyldichloroethylene [p,p'-DDE]) accumulation potential in xylem sap and tissues of parental, F1 hybrids, and F1 backcross (BC) generations of plants. Plants were grown in pots containing soil with weathered DDX at 732 to 1,130 ng/g soil or under field conditions in soil with 322 to 2,700 ng/g.

Accumulation of weathered pp'-DDE in xylem sap of grafted watermelon.

Movement of weathered p,p'-dichlorodiphenyldichloroethane (p,p'-DDE) from contaminated soil to the rhizosphere pore water to the xylem sap of grafted watermelon was studied under green house conditions. p,p'-DDE concentrations in pore water and xylem sap was compared in intact plants, homografted, and compatible heterografts of Cucurbita pepo spp. pepo and Citrullus lanatus plants.

Accumulation of weathered p,p'-DDTs in grafted watermelon.

The grafting of melon plants onto cucurbit rootstocks is a common commercial practice in many parts of the world. However, certain cucurbits have been shown to accumulate large quantities of weathered persistent organic pollutants from the soil, and the potential contamination of grafted produce has not been thoroughly evaluated. Large pot and field experiments were conducted to assess the effect of grafting on accumulation of weathered DDX (the sum of p,p'-DDT, p,p'-DDD, and p,p'-DDE) from soils.