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In 1996 Shen-Miller and colleagues traveled to northeastern China to visit the site of collection of the oldest living seed, a sacred lotus dated at about 1300 years old (AJB 82: 1367-1380). Viable seeds newly collected from the site measured between 200 and 500 years old and soil from the lotus-bearing beds showed low-dose background -radiation (~2 mGy/yr, 1 Gy [gray] = 100 rad). All five seedlings germinated from this collection showed abnormalities similar to those produced in modern plants by -irradiation at much higher doses. The cultivation of offspring from old seeds directly radiocarbon dated is a first in plant biology. The total accumulated -radiation of 0.1-1.0 Gy for these seeds represents the longest natural radiobiology experiment yet recorded. (see p. 236)

Mirror-image flowers

Jesson and Barrett provide the first comparative study of enantiostyly, a curious sexual polymorphism involving mirror-image flowers with styles deflected either to the right or left side of the flower. They demonstrate that in Wachendorfia (Haemodoraceae), a small genus of geophytes restricted to South Africa, style-morph frequencies are governed by the reproductive systems of populations, with 1:1 frequencies maintained in outcrossing populations, and biased morph ratios in populations with high selfing rates or clonal propagation. The study clearly illustrates how interactions between reproductive traits and ecology can play a key role in the maintenance of sexual polymorphisms in plants. (see p.253)

New technique for sourcing phytoliths

Carnelli et al. present a new technique for distinguishing between phytoliths produced by woody species and those produced by grasses. Phytoliths are silicified plant microfossils that are used by palaeoecologists in the reconstruction of the history of vegetation. The authors used X-ray microanalysis to screen plant silica extracted from 20 species of Gramineae, Cyperaceae, Ericaceae, and Coniferae of the Valaisan Swiss Alps. Among the taxa investigated, only woody species produced a high proportion of phytoliths containing aluminum. This distinction should help in more accurately reconstructing historical shifts between grasslands and woodlands. (see p. 346)

Sectoriality meets patchiness

Orians et al. show skillfully that the uptake of patchily distributed nutrients by a sectorially organized plant, in this case tomato, produces sectorial responses in the developmental commitment of meristems, the growth of organs, and the production of phenolics. Specifically, leaflets with direct vascular connections to fertilized lateral roots were larger and had lower levels of defensive chemicals than did leaflets in sectors lacking connections. Moreover, branching was more likely to occur in the fertilized sectors. There are important implications for ecological and agricultural systems and plant-herbivore relations. (see p. 270)

This Article Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Search for Related Content