RECOVERY OF NATIVE AND APPLIED AUXIN FROM THE DARK-GROWN ‘ALASKA’ PEA SEEDLING

Scott, Tom K., and Winslow R. Briggs. (Stanford U., Stanford, Calif.) Recovery of native and applied auxin from the dark-grown ‘Alaska’ pea seedling. Amer. Jour. Bot. 50(7): 652–657. Illus. 1963.—The distribution and movement of “free” endogenous and applied auxin were determined in the 7-day-old dark-grown ‘Alaska’ pea epicotyl by means of short-term ether extraction. A general decrease in total endogenous auxin content took place from apex to base within the growing as well as the non-growing regions. Factors other than growth itself may be responsible for this decrease. Auxin distribution changes, as they occur following the removal of the apical bud, may reflect an incompletely polar transport system operating in the epicotyl. This suggestion was supported by following the movement of indole-3-acetic acid applied in lanolin paste. The results presented are related to similar experiments performed on the light-grown ‘Alaska’ pea seedling as well as on other vascular plants.     

QUANTITATIVE CHANGES IN GIBBERELLIN AND RNA CORRELATED WITH SENESCENCE OF THE SHOOT APEX IN THE ‘ALASKA’ PEA

Senescence of shoot apices of Pisum sativum L. ‘Alaska’ as measured by cessation of stem elongation was delayed by removal of flowers and by treatment with gibberellin A₃ and was hastened by treatment with AMO-1618 (2 isopropyl-4-dimethylamino-5-methylphenyl-1-piperi-dinecarboxylate methyl chloride). Ontogenetic changes in relative endogenous gibberellin levels and in capability of gibberellin biosynthesis in deflowered and control plants were determined indirectly by studying time-course changes in the sensitivity, as indicated by the growth response, of these plants to applied gibberellin and AMO-1618. The results of these experiments suggest that the endogenous gibberellin level varies directly with the growth rate. Analyses of total RNA and protein in shoot tips of deflowered and control plants revealed that the levels of these substances also vary directly with growth rate throughout ontogeny. It is concluded that decreases in endogenous gibberellin, RNA and protein are factors correlated with senescence of the shoot apex.     

TRANSPIRATION FROM THE SPOROPHORE OF AGARICUS BISPORUS ‘WHITE’

The transpiration from normal, intact, growing sporophores of the cultivated mushroom, Agaricus bisporus cv ‘White’ was determined by a gravimetric method. A simple method was devised to estimate the surface area of a sporophore. Under different conditions of temperature and relative humidity, the quotient of transpiration/cm² sporophore surface area and evaporation/cm² free-water surface area did not significantly differ from 1. Transpiration from the underside of an open-veil mushroom was related to the planar area rather than to the total exposed gill area. Normally growing sporophores transpired up to 3 mg/cm²/hr. It was estimated that during development to the open-veil stage, a sporophore transpired a quantity of water equal to ca. one-half of its fresh weight. There was no evidence of factors other than environmental affecting the evaporation of water from the surface of the normally growing sporophore. Our data were not extensive enough, however, to provide evidence for or against Schütte's hypothesis that transpiration in a mature agaric fructification may be intimately linked with a physiological process.     

SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS : III. SULFHYDRYL GROUPS OF NATIVE PROTEINS—HEMOGLOBIN AND THE PROTEINS OF THE CRYSTALLINE LENS

Hemoglobin and the proteins of the crystalline lens contain active SH groups while in the native state, the number of active groups increasing as the pH rises. All the SH groups of denatured globin and of the denatured lens proteins are active at a pH so low that practically none of the SH groups of native hemoglobin and of native lens protein are active. The effect of denaturation on the SH groups of a protein is to extend towards the acid side the pH range of their activity. It is possible to oxidize the iron-porphyrin and the SH groups of hemoglobin independently of each other.     

THE STUDIES OF THE PLANT COLD－RESISTER AND ITS APPLICATION IN RECE SEEDLING RAISING

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LOSS OF GIBBERELLINS BY LEACHING FROM STEMS AND FOLIAGE OF CHRYSANTHEMUM MORIFOLIUM ‘PRINCESS ANNE’

Structurally complex metabolites such as carbohydrates, organic acids, and amino acids are leached from plants by rain and dew. Applied GA₃ (1 mg/ml) absorbed by a 5-cm stem segment of Chrysanthemum morifolium and translocated to a single attached leaf was leached from the leaf with distilled water. To detect endogenous gibberellins in plant leachates, Chrysanthemum morifolium ‘Princess Anne’ plants were leached under 8-hr and 18-hr photoperiods. The leachates were collected and extracted at pH 8.2 with methylene chloride to*** remove inhibitors and at pH 3.0 to remove gibberellins. The extract containing the gibberellins was fractionated on a silica gel column by an eluting phase of 0 to 100% ethyl acetate-n-hexane solutions. The presence of gibberellin-like substances was confirmed by their elution pattern from the silica gel column and by two bioassays, the lettuce hypocotyl and the Rumex bioassays. The results suggest that substances similar to GA_1–3 and GA₅ were leached from plants growing under an 18-hr photoperiod. The leachate from plants growing under an 8-hr photoperiod contained gibberellin-like substances similar to GA_1–3 and GA₆.     

A MORPHOLOGICAL AND HISTOLOGICAL STUDY OF THE TOMATO MUTANT ‘CURL’

The dominant tomato mutant ‘Curl’ differs from normal plants in several striking respects including the following: misshapen laminar structures such as leaves, sepals, and petals; stunted petiole and rachis; and persistent growth of blade and stem tissue from the adaxial surface of the rachis. These tissues as well as others which appear morphologically normal show gross histological abnormalities. Also evident in sections of mutant tissue is the appearance of areas containing numerous crystalline inclusions and a lack of bodies showing a stainable starch reaction in palisade and mesophyll of leaves and in endodermis and pith cells of the stem.     

CYTOGENETICS OF RUBUS. II. CYTOLOGICAL STUDIES OF THE VARIETIES ‘YOUNG,’ ‘BOYSEN,’ AND RELATED FORMS

Thompson , Maxine M. (U. California, Davis.) Cytogenetics of Rubus. II. Cytological studies of the varieties ‘Young,’ ‘Boysen’ and related forms. Amer. Jour. Bot. 48(8): 667–673. Illus. 1961.—Chromosome numbers are given for the trailing blackberry varieties, ‘Young’ (2n = 49), ‘Boysen’ (2n = 49), ‘Nectar’ (2n = 49) and for related forms which include the parents of ‘Young,’ ‘Phenomenal’ (2n = 42) and ‘Mayes’ (2n = 56), and 3 cytologically resynthesized ‘Young’ plants (2n = 49) as a basis for interpreting the postulated origin of ‘Young.’ Cytological evidence substantiated the conclusion that ‘Young’ is a hybrid between ‘Phenomenal’ and ‘Mayes.’ Contributions to the understanding of genomic relationships in Rubus are offered from detailed analyses of meiosis in ‘Phenomenal,’ ‘Mayes,’ ‘Young,’ and ‘Boysen.’ ‘Phenomenal’ and ‘Mayes’ both had a very regular meiosis. ‘Young,’ as well as ‘Boysen,’ showed a greater degree of chromosome association than either parent of ‘Young.’ Meiotic behavior in ‘Boysen’ presented a close parallel to that of ‘Young’ which, correlated with morphological similarities and the same 2n chromosome number, suggests a similar origin. The mode of reproduction in ‘Young’ and ‘Boysen’ was found to be sexual on the basis of morphological variation in the open-pollinated (selfed) progeny, the varying aneuploid somatic chromosome numbers in these progeny (2n = 32–54) and aneuploid chromosome numbers in hybrids having either variety as one parent. The productiveness of ‘Young’ and ‘Boysen’ in commercial plantings and their successful utilization in breeding programs indicate a high fertility regardless of their having an odd multiple of the basic number. It is concluded that the production of balanced euploid gametes is not necessarily a criterion of fertility, at least not at this high level of ploidy.     

METAMORPHOSIS OF THE LARVA OF THE POLYCHAETE ARENICOLA CRISTATA. MORPHOLOGY OF THE ‘HOUR-GLASS’ STAGE

The constricted ‘waist’ of the metamorphosing larva of the polychaete Arenicola cristata is described, using light and electron microscopy. The constriction is shown to be the consequence of the discharge and collapse of a post-trochal ring of epithelial cells which remain as functional components of the post-metamorphic juvenile. Morphological differentiation of neuro-effector and interneuronal contacts is initiated at this time. Muscular and neural changes are discussed in terms of their role in effecting metamorphosis.     

THE ‘ MEDITERRANEAN ’RAMALINA PANIZZEINORTH OF THE ALPS: MORPHOLOGICAL,CHEMICAL AND rDNA SEQUENCE DATA

Ramalina panizzei De Not. is reported from Switzerland and north of the Alps for the first time. Recent collections and thalli found amongst specimens ofR. fastigiata(Pers.) Ach. are described; the species is obviously not restricted to the Mediterranean. The confusion in several herbaria around this and related corticolous species, particularlyR. subgeniculataNyl. andR. fastigiata, can be traced back to imprecise original and subsequent diagnoses, all of which lack a clear species delimitation. Similarities and differences of these species are discussed. In addition, sequences from the rDNA ITS regions were determined for two individuals ofR. panizzeiand two ofR. fastigiata, including one of each from a site where both species grow intermixed. Kimura 2-parameter genetic-distance estimates indicate thatR. panizzeiandR. fastigiataare as different from each other as either is from the reference speciesR. siliquosa(Hudson) A. L. Sm.s.l.A broad-based taxonomic revision of involved species is not possible due to the limited number of analyses, but the results demonstrate the potential for using DNA sequence data to investigate species-level questions in lichens. Based on morphology, chemistry, and DNA sequence data,R. panizzeiis retained as a distinct species.     

THE RELEVANT USE OF THE TRADITIONAL TUNISIAN GAME ‘‘RAQASSA’’ FOR CARDIOVASCULAR STIMULATION IN SCHOOLCHILDREN

The aim of this study was to investigate the heart rate (HR) responses, the rate of perceived exertion (RPE), and the feeling during physical education schooling while performing traditional games activities compared to intermittent exercise. Nineteen pre-pubertal children randomly performed on different days two types of lessons (intermittent running mode vs. traditional Tunisian “Raqassa” game) lasting 12-min each. HR was continuously recorded during both lessons, while ratings of perceived exertion and Feeling values were recorded after the sessions. The mean HR value during the traditional game was significantly higher than during intermittent exercise (p<0.05). Conversely, the perceived exertion score was significantly higher after intermittent exercise than the traditional exercise game (p<0.05), showing that the higher cardiovascular strain of the game was perceived as “lighter” than the run. Simultaneously, the children''s Feeling was significantly higher after the traditional game than intermittent exercise (p<0.001), showing a higher satisfaction from playing with respect to running. Exercise based on the “Raqassa” traditional game could be used in pre-pubertal children as an alternative or as an additional method for suitable cardiovascular stimulation during physical education lessons with lower perceived exertion and better feeling compared to intermittent running.