Showing papers on "Polygonum published in 1971"

Comparative leaf structure of aquatic polygonum species

Abstract: A B S T R A C T A systematic study of leaf morphology and anatomy of native, aquatic Polygonum species is presented, treating 60 populations propagated in a common greenhouse On the basis of this study it is now possible to distinguish American Polygonum species by leaf characters alone Taxa in section Persicaria are contrasted and also compared with representatives of sections Bistorta and Echinocaulon A complete description, utilizing 40 leaf characters, is given for each taxon Complex glands, designated valvate chambers, are shown to be a consistent feature of the P punctatum species-complex, whereas epidermal storage-idioblasts are present only in certain populations of this group All other species lack valvate chambers but possess idioblasts, which may reach a frequiency of over 400/mm2 in P hirsutum The plate-like multicellular gland of P opelousanum is found to occur sporadically in P hydropiperoides, thereby losing its specific diagnostic value Illucidation of the characteristic structure of this gland, however, lends evidence to discourage the theory that it is an abortive structure produced by a hybrid between glandular and non-glandular species Reticulate venation and unicellular trichomes separate members of section Bistorta from the smartweeds, but P meisnerianum (section Echinocauilon) is shown to simulate leaf struicture of the persicarias both internally and externally

Studies on weed species of the genus polygonum vii. effect of nutrition and other factors on seed characteristics and germination behaviour of p. lapathifolium

Abstract: Summary. . Plants of Polygonum lapathifolium were grown either in a glasshouse or outside, at a high or a low level of mineral nutrition, and either with or without competition from barley. The viability and percentage emergence of seedlings from germinated seeds (planted in sterile compost) were higher with seed from glasshouse-grown plants. High nutrition increased plant weight, seed production and seed weight, and also increased seedling emergence. Competition reduced plant weight, but had only a small, non-significant, effect on seed production. Seed from plants grown with competition had a greater percentage seedling emergence from germinated seeds.