testa

plural testas · plural testae · plural testæ

1. biologyA seed coat.

   The testa develops from the tissue, the integument, originally surrounding the ovule.

   5 more examples

   The seeds are furnished with a reticulated testa, very much in appearance like that of the seeds of two closely-allied pericarps in the cabinet of my friend Mr. Ward, of Wellclose-square, the names of which I have been unable to obtain, but which present strong evidence of belonging to the Malvaceæ.

   1840, James Scott Bowerbank, A History of the Fossil Fruits and Seeds of the London Clay, page 30

   1969, C. W. Bennett, Seed Transmission of Plant Viruses, Alison Smith, Advances in Virus Research, Volume 14, page 224, In tests with the Lincoln and Virginia varieties of cowpea, Crowley (1959) found that, in plants infected with bean southern mosaic virus before blossoming, the virus was present in nearly 100% of the testae and endosperms of seeds of both varieties, but could not be detected in the embryos.

   Thus, two conditions must be satisfied for the testas to have this effect: contact between the testas and the radicle, and the presence of at least half of the testas.

   1977, Commonwealth Scientific, Industrial Research Organization, Australian Journal of Plant Physiology, page 354

   2005, D. W. Dickson, D. De Waele, Nematode Parasites of Peanut, Michel Luc, Richard A. Sikora, John Bridge, Plant Parasitic Nematodes in Subtropical and Tropical Agriculture, page 419, A. arachidis is a parasite of pods, testae, roots and hypocotyls, but not the cotyledons, embryos or other parts of the plant (Bos, 1977a; Bridge et al., 1977).

   One of the most remarkable features of cultivated beans is the enormous range of testa colours and patterns which can be found.

   2007, J. Smartt, “Evolution of American Phaseolus beans under domestication”, in Peter John Ucko, G. W. Dimbleby, editors, The Domestication and Exploitation of Plants and Animals, page 458

2. marine biologyThe external calciferous shell, or endoskeleton, of an echinoderm; the test.

plural Testas

1. A surname from Italian.