(American Journal of Botany. ;90:0.)
© Botanical Society of America, Inc.
Conditions for nonrandom mating
A study by Shaner and Marshall expands past investigations of seed paternity in wild radish (Raphanus sativus). Nonrandom mating is known to occur in this species under optimal greenhouse conditions. Their investigation asks whether nonrandom mating is maintained under a wider range of conditions, including drought and varied pollen load size. A major strength of the work is the care with which the authors control and/or account for factors that might have otherwise confounded the results, for example, by testing the stigmas for pollen numbers and measuring differences in pollen number per flower.
(see p. 1604)
Vochysiaceae flowers, characterized by reduced petal number, spurred calyx, and single fertile stamen, are the subject of two papers by Litt and Stevenson in this issue. Their SEM and serial sectioning data describe the structure and development of these flowers in detail for the first time. The floral structure of many Vochysiaceae has been difficult to interpret because the flowers are asymmetric. The authors provide new insight into this problem through their carefully produced and well-illustrated developmental and anatomical studies in all relevant taxa of the family.
(see p. 1533 and p. 1548)
Eisinger, Bogomolni, and Taiz consider the photobiology and photoregulation of stomatal opening in plants. Using several Arabidopsis mutants, they studied the interaction of a blue-green reversible photoreceptor and a UV-B photoreceptor. They propose a model for a complex photoreceptor network, noting that the era of simple linear photoreceptor models is over.
(see p. 1560)
Birnbaum et al. make a valuable contribution to the literature on genetic erosion and in situ conservation of crop genetic resources in a comprehensive and innovative study of the impact of farming practice, especially choice of cultivar and planting layout, on gene flow in avocado (Persea americana) groves. The combination of methods, including ethnographic surveys, molecular marker assays, and gene flow simulation provides a strong basis for the conclusions. And apparently the personal preferences of farmers and the changing whims of consumers are doing much to maintain species diversity.
(see p. 1619)
