Suberization and adventitious rooting in Australian plants

1984 ◽  
Vol 32 (4) ◽  
pp. 363 ◽  
Author(s):  
RR Williams ◽  
AM Taji ◽  
JA Boltton

Controversy has existed over the involvement of sclerified tissues in the inhibition of adventitious rooting on woody plant cuttings. This study of 16 species of Australian native plants shows no correlation between stem sclerification and poor root formation. On the other hand, poor rooting was correlated with suberization of the cortex and it is suggested that this rather than sclerification may be a factor in the inhibition of root formation.

2020 ◽  
Vol 73 (1) ◽  
pp. 9039-9046
Author(s):  
Rodrigo Alberto Hoyos Sanchez ◽  
Diego Chicaíza Finley ◽  
Juan Carlos Zambrano Arteaga

Carludovica palmata Ruíz & Pavón is a plant that belongs to the Cyclanthaceae family. Its commercial interest is related to the production of fibers for the manufacture of handicrafts, mainly the Panama hat, so it is important to study its propagation. This investigation aimed to determine the effect of 6-benzylaminopurine (BAP) in the formation of new shoots and 1-naphthaleneacetic acid (NAA) in the formation of roots, as well as the adaptation in greenhouse conditions of Carludovica palmata Ruíz & Pavón. In order to find the optimal multiplication rate, 0.5 cm length explants were planted in glass jars with 15 mL of semisolid MS with different concentrations of BAP and cultured under in vitro conditions for 90 days. The multiplication parameters in this stage were number of shoots per explant (NSE), length of shoots (LS), and length of roots (LR) as multiplication parameters. In a similar procedure, the number of roots per explant (NRE), length of roots (LR), and length of plantlets (LP) was determined using different concentrations of NAA. Finally, different substrates were evaluated for the adaptation of plantlets of C. palmata produced in vitro, under greenhouse conditions for 80 days. The highest multiplication rate (17±3 shoots per explant) was obtained with 2.0 mg L-1 of BAP. Root formation occurred efficiently in all treatments, without significant statistical differences between them. On the other hand, the use of substrate soil-t15 was the best treatment for the growth of C. palmata under greenhouse conditions. From the results obtained, it is concluded that C. palmata can be efficiently multiplied under in vitro conditions and did not present problems during the in vivo rooting process.


2015 ◽  
Vol 43 (1) ◽  
pp. 229-234
Author(s):  
Gregor OSTERC ◽  
Franci STAMPAR ◽  
Valentina SCHMITZER

Leafy cuttings of Prunus subhirtella Miq. ‘Autumnalis’ were harvested from mature, semi-mature and juvenile stock plants at four dates during the vegetative period 2011 (on 16th of May, on 30th of May, on 20th of June and on 11th of July) and their auxin levels (IAA, IAA-Asp) and sugar content (glucose, sucrose, sorbitol) were quantified. The IAA and IAA-Asp contents in cutting bases increased over the vegetative period, whereby aspartate values were higher than IAA values. The IAA-Asp values ranged from 6.3 µg g-1 to 22.7 µg g-1 FW and reached two great peaks on 30th of May and on 11th of July. The IAA values ranged from 0.29 µg g-1 to 4.51 µg g-1 FW, reaching a small fall on 20th of June. Significantly higher levels of IAA and IAA-Asp were measured at the base of mature cuttings compared to cuttings of semi-mature and juvenile origin, when the cuttings were harvested on 30th of May and on 11th of July. On the other hand, mature leafy cuttings accumulated significantly less fructose and glucose in their root emergence zone (16.3 g kg-1 DW, 45.2 g kg-1 DW) compared to semi-mature cuttings (26.4 g kg-1 DW, 62.5 g kg-1 DW) and juvenile cuttings (27.3 g kg-1 DW, 73.9 g kg-1 DW). All measured rooting parameters (rooting success, number of main roots and root length) were significantly improved when cuttings of a more juvenile origin (semi-mature and juvenile) were used.


1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.


Author(s):  
A. V. Crewe

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.


Author(s):  
K.H. Westmacott

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.


2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.


Author(s):  
Stefan Krause ◽  
Markus Appel

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.


2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.


1961 ◽  
Vol 6 (6) ◽  
pp. 222-223
Author(s):  
Edwin G. Boring
Keyword(s):  

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