Plant morphology

About: Plant morphology is a research topic. Over the lifetime, 1174 publications have been published within this topic receiving 24418 citations. The topic is also known as: phytomorphology & morphology of higher plants.

Pollenizer plants for use in the production of seedless watermelon

Abstract: This invention relates to a pollenizer watermelon plant, for use in the production of seedless watermelon. The pollenizer plant is characterized by at least two of the following features: (a) distinguishable fruit phenotype; (b) high number of male flowers; (c) continued flowering; (d) early flowering; and/or (e) modified plant morphology and growth habit. The invention particularly relates to plants having the characteristics of plants grown from the seed deposited at the ATCC under ATCC accession number 203691. The invention further relates to plants obtainable by propagation of, and/or breeding with a watermelon plant grown from the seed deposited at the ATCC under ATCC accession number 203961.

Occurrence and physiological breakdown of self-incompatibility in easter cactus

Abstract: The existence of self-incompatibility (SI) was demonstrated in 'Britton' and 'Rose' Easter cactus ( Rhipsalidopsis). In a full diallel cross among five clones, 18 out of 20 outcrosses resulted in 68% to 100% fruit set, whereas reciprocal crosses between two of the clones and all five self-pollinations failed to set fruit. Pollen tube growth was greatly inhibited in styles of selfed pistils, but there was no evidence of pollen tube inhibition in compatibly crossed pistils. Easter cactus exhibited characteristics typically found in sporophytic SI systems (trinucleate pollen, papillate stigmas, and scant stigmatic exudate) together with those associated with gametophytic SI systems (stylar inhibition of pollen tube growth and absence of reciprocal differences in outcrosses). Additional experiments were performed to determine the effects of bud pollinations, growth regulators (BA, GA 3 , and NAAm), and high temperatures (0- to 48-h exposure at 40C) on the SI response. Heat treatments were more effective than either bud pollinations or growth regulators in overcoming SI, and yielded an average of 7.2 viable seeds per treated flower when plants were incubated for 12 h at 40C and selfed immediately after incubation. Isozyme analysis of the S 0 parent and putative S 1 progeny confirmed that selfing had occurred following heat treatments. Using S 1 progeny in breeding programs may extend the flower color range and lead to a greater diversity in other plant characteristics than presently exists in cultivated germplasm. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (benzyladenine (BA)), gibberellic acid (GA 3 ), and α-naphthaleneacetamide (NAAm). The genus Rhipsalidopsis, commonly known as Easter cactus, encompasses two species of epiphytic or lithophytic shrubs that are native to southeastern Brazil (Liberty Hyde Bailey Hortorium, 1976). Plants are composed of a series of discrete, flattened or angular stem segments (phylloclades). Rhipsalidopsis rosea (Lagerheim) Britt. & Rose is a compact plant with phylloclades 2.5 to 3.8 cm long and rose-pink flowers 2.5 to 3.8 cm wide (Moran, 1953). Rhipsalidopsis gaertneri (Regel) Moran is larger than R. rosea and has phylloclades 3.8 to 7.6 cm long and bright red flowers 6.4 to 8.9 cm wide (Moran, 1953). Cultivars of Easter cactus include clonal selections of R. rosea, R. gaertneri, and their interspecific hybrids ( R. ×graeseri (Werdermann) Moran). Com- mercial interest in Easter cactus is increasing in North America due to its potential as a flowering pot plant (Boyle and Stimart, 1989). Self-incompatibility (SI) is a genetically controlled mechanism that prevents fertilization in fertile hermaphroditic plants when they are selfed or crossed to another plant with an identical incompatibility phenotype (de Nettancourt, 1977). Major reviews on the distribution of SI in angiosperms do not document any cases of SI for the Cactaceae (Brewbaker, 1957, 1959; East, 1940; Fryxell, 1957). However, several reports suggest that SI is wide- spread in the Cactaceae (Breckenridge and Miller, 1982; Ganders, 1976; Ross, 1981; Taylor, 1976). Ganders (1976) and Taylor (1976), observing a lack of fruit set following selfing, concluded that SI was present in R. gaertneri and R. rosea, respectively. In a preliminary investigation, we self-pollinated several cultivars of Easter cactus but failed to obtain fruit set, thus corroborating Gander's (1976) and Taylor's (1976) results (T.H. Boyle, unpub- lished data). Increased variability in Easter cactus would be beneficial for greater diversity in plant morphology and flower color. It would therefore be desirable to recover S 1 progeny to obtain plants homozygous for recessive genes affecting plant habit and flower color. The purpose of this study was to 1) identify factor(s) preventing fruit set following self-pollination and 2) determine the effects of growth substances, heat treatments, and timing of pollination on yields of self-seed.

Morphological and anatomical evaluation of adult and juvenile leaves of olive plants

Abstract: The olive tree (Olea europaea L.), like many other woody plants, has a long juvenile period in which the plant is not able to produce flowers. Knowledge of the moment when the plant is capable of flowering is important for breeding programs and also for determining the physiological basis for sexual reproductive behavior, but currently the only indicator of that moment is the actual flowering. In many species, the juvenile-to-adult phase shift includes changes in leaf structure known as heteroblasty, that is, varied form of successive leaves on the same plant. Some differences have been observed between juvenile and adult olive leaves, particularly in size and form, but to our knowledge, no complete systematic study has been carried out. In this research, we measured size, morphology and anatomy for juvenile and adult leaves of olive plants grown from seeds. Differences were found in most of the parameters studied, including leaf size, form, mesophyll thickness, layers of palisade parenchyma and quantity of peltate trichomes, which were generally significant but overlapping between the two leaf types. The most consistent and striking difference was the presence of an organized layer of subepidermal cells only in the abaxial mesophyll of adult leaves. This characteristic could be a simple and effective criterion of phase change in the olive tree.