Buds on the roots of Hieracium florentinum (hawkweed)

1971 ◽  
Vol 49 (1) ◽  
pp. 53-54 ◽  
Author(s):  
R. L. Peterson ◽  
A. G. Thomas

Hieracium florentinum All. reproduces vegetatively by adventitious buds which have been shown by anatomical studies to arise from roots. Culture experiments indicate that undamaged roots and isolated root tips have the capacity for bud initiation. Vegetative propagation by means of root-borne buds is important in the expansion of existing populations of H. florentinum.

1960 ◽  
Vol 38 (2) ◽  
pp. 243-249 ◽  
Author(s):  
Trilochan S. Bakshi ◽  
Robert T. Coupland

Vegetative propagation in Linaria vulgaris is obtained by the development of numerous adventitious buds on its roots. Each bud originates exogenously on the parent root, and it is always associated with a lateral root which arises in the pericycle opposite a protoxylem point. Buds capable of vegetative propagation are not found on either the hypocotyl or the stem. This appears to be correlated with the absence in roots of the typical open type of lenticels and of any significant accumulation of starch. Soil disturbance seems to have a deleterious effect on the production of buds on roots.


1981 ◽  
Vol 59 (1) ◽  
pp. 68-74 ◽  
Author(s):  
S. Oka ◽  
K. Ohyama

Leaf explants of mulberry (Mortis alba L.) derived from aseptically grown shoots and seedlings were cultured on Murashige and Skoog's medium. Normal and abnormal leaves were grown by varying the concentration of benzyladenine. They differed in the way of forming adventitious buds. In normal leaves bud initiation occurred exclusively at the cut ends of midribs after removing petioles, while in abnormal ones buds formed at any region on midribs and petioles. Histological observations were made to study different patterns of bud initiation.


1979 ◽  
Vol 57 (19) ◽  
pp. 1986-1993 ◽  
Author(s):  
Simonne Rivière ◽  
Jean-François Muller

Vegetative propagation of tulips in vitro, not performed until now, is obtained using as explants scales of daughter bulbs collected in winter. Twenty-five percent of these explants give rise to neoformed buds within 6 months. These buds evolve into bulbs which are able to develop in the soil. Their ontogeny is studied histologically, from the beginning of the culture to the neoformed bulb formation. A treatment with low temperature and darkness at the beginning of the culture period promotes an earlier bud initiation.


HortScience ◽  
2002 ◽  
Vol 37 (6) ◽  
pp. 885-889 ◽  
Author(s):  
Abraham H. Halevy ◽  
Menashe Levi ◽  
Menashe Cohen ◽  
Vered Naor

Experiments to advance early production of herbaceous peony (Paeonia lactiflora Pall.) flowers were conducted over 8 years in the higher elevation, cooler regions of Israel. Anatomical studies during the summer revealed that flower bud initiation of apical buds in the crowns began at the end of July and continued also in lateral buds from mid-August until the plants became dormant in mid-November. Container-grown plants of various cultivars were moved to cold rooms maintained for 10 to 13 weeks at 2 °C, from mid-August to mid-October, then drenched with 250 mL of various concentrations of GA3 and transferred to a greenhouse. The optimal GA3 concentration for flower production was 100 mg·L-1. Plants treated in this way flowered 2-3 months before the natural flowering period. Field-grown plants in uncovered greenhouse structures were exposed to natural winter cold temperatures (0-10 °C), until they had received various chill units according to a “dynamic model” (for details see Erez et al., 1988). The crowns were then drenched with various amounts and concentrations of GA3, and the greenhouses were covered with plastic sheets. The optimal chill units for most cultivars was 40 and the optimal GA3 drench treatment was 250 mL of 100 mg·L-1. Covered and GA3-treated field-grown plants flowered ≈1 month earlier than untreated plants grown in the open field. The GA3 treatment also greatly increased the number of produced flowers.


Author(s):  
M. Arif Hayat

Although it is recognized that niacin (pyridine-3-carboxylic acid), incorporated as the amide in nicotinamide adenine dinucleotide (NAD) or in nicotinamide adenine dinucleotide phosphate (NADP), is a cofactor in hydrogen transfer in numerous enzyme reactions in all organisms studied, virtually no information is available on the effect of this vitamin on a cell at the submicroscopic level. Since mitochondria act as sites for many hydrogen transfer processes, the possible response of mitochondria to niacin treatment is, therefore, of critical interest.Onion bulbs were placed on vials filled with double distilled water in the dark at 25°C. After two days the bulbs and newly developed root system were transferred to vials containing 0.1% niacin. Root tips were collected at ¼, ½, 1, 2, 4, and 8 hr. intervals after treatment. The tissues were fixed in glutaraldehyde-OsO4 as well as in 2% KMnO4 according to standard procedures. In both cases, the tissues were dehydrated in an acetone series and embedded in Reynolds' lead citrate for 3-10 minutes.


Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.


Author(s):  
Y. R. Chen ◽  
Y. F. Huang ◽  
W. S. Chen

Acid phosphatases are widely distributed in different tisssues of various plants. Studies on subcellular localization of acid phosphatases show they might be present in cell wall, plasma lemma, mitochondria, plastid, vacuole and nucleus. However, their localization in rice cell varies with developmental stages of cells and plant tissues. In present study, acid phosphatases occurring in root cap are examined.Sliced root tips of ten-day-old rice(Oryza sativa) seedlings were fixed in 0.1M cacodylate buffer containing 2.5% glutaraldehyde for 2h, washed overnight in same buffer solution, incubated in Gomori's solution at 37° C for 90min, post-fixed in OsO4, dehydrated in ethanol series and finally embeded in Spurr's resin. Sections were doubly stained with uranyl acetate and lead citrate, and observed under Hitachi H-600 at 75 KV.


Author(s):  
J. A. Traquair ◽  
E. G. Kokko

With the advent of improved dehydration techniques, scanning electron microscopy has become routine in anatomical studies of fungi. Fine structure of hyphae and spore surfaces has been illustrated for many hyphomycetes, and yet, the ultrastructure of the ubiquitous soil fungus, Geomyces pannorus (Link) Sigler & Carmichael has been neglected. This presentation shows that scanning and transmission electron microscopical data must be correlated in resolving septal structure and conidial release in G. pannorus.Although it is reported to be cellulolytic but not keratinolytic, G. pannorus is found on human skin, animals, birds, mushrooms, dung, roots, and frozen meat in addition to various organic soils. In fact, it readily adapts to growth at low temperatures.


Author(s):  
P.T. Nguyen ◽  
C. Uphoff ◽  
C.L. Stinemetz

Considerable evidence suggest that the calcium-binding protein calmodulin (CaM) may mediate calcium action and/or transport important in the gravity response of plants. Calmodulin is present in both shoots and roots and is capable of regulating calcium transport in plant vesicles. In roots calmodulin is concentrated in the tip, the gravisensing region of the root; and is reported to be closely associated with amyloplasts, organelles suggested to play a primary role in gravi-perception. Inhibitors of CaM such as chlorpromazine, calmidazolium, and compound 48/80 interfere with the gravitropic response of both snoots and roots. The magnitude of the inhibition corresponded well with the extent to which the drug binds to endogenous CaM. Compound 48/80 and calmidazolium block gravi-induced changes in electrical currents across root tips, a phenomenon thought to be associated with the sensing of the gravity stimulus.In this study, we have investigated the subcellular distribution of CaM in graviresponsive and non-graviresponsive root caps of the maize cultivar Merit.


Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.


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