Phenology, morphology and reproductive biology of the tuberous sundew, Drosera erythrorhiza Lindl

1978 ◽  
Vol 26 (4) ◽  
pp. 441 ◽  
Author(s):  
KW Dixon ◽  
JS Pate
Keyword(s):  
Fire History ◽  
Soil Surface ◽  
Reproductive Behaviour ◽  
Growth Cycle ◽  
Axillary Shoot ◽  
Seasonal Growth ◽  
Axillary Shoots ◽  
Growth And Survival ◽  
Tuber Production ◽  
Daughter Tuber

The seasonal growth cycle of Drosera erythrorhiza was examined in native habitat near Perth, W.A. Vegetative growth was from autumn to late spring (March to October), aestivation by underground tubers from November to February. Each germinating tuber produced an upward growing stem terminated at the soil surface by a rosette of glandular leaves. Light was required to initiate the rosette. New tubers formed during July and August. A positively geotropic axillary shoot (dropper) developed from the stem base and penetrated the epidermal sheath(s) of the parent tuber to form a replacement tuber within the emptying storage tissues of its parent. Diageotropic axillary shoots (rhizomes), produced higher up the stem, extended radially, each swelling terminally to produce a daughter tuber. Plants flowered profusely only after fire, and were not observed to reproduce from seed. Reproduction of clones was analysed in terms of number and depth of placement of parent and daughter tubers. Age structure of clones was studied by counting epidermal sheaths surrounding tubers. Clones appeared to undergo cyclic rejuvenation, periods of intensive daughter tuber production alternating with periods of minimal reproduction. Soil type, fire history and season modified this reproductive behaviour by affecting the intensity of daughter tuber production and the growth and survival of tubers.

Biology and natural history of Caladenia

2009 ◽  
Vol 57 (4) ◽  
pp. 247 ◽  
Author(s):  
Kingsley Dixon ◽  
Raymond L. Tremblay
Keyword(s):  
Natural History ◽  
Arid Zone ◽  
Secondary Infection ◽  
Soil Surface ◽  
Growth Cycle ◽  
Cortical Cells ◽  
Herbaceous Perennials ◽  
Terrestrial Orchids ◽  
History Of ◽  
Soil Wetting

The genus Caladenia comprises species that exhibit remarkable consistency in terms of growth form and phenological patterns. All taxa are herbaceous perennials, with the shoot arising annually from a single, usually spheroid, tuber and producing a single, hairy leaf. The tuber is annually replaced either side-by-side with the parent tuber or terminating a descending structure known as a dropper. The dropper is a depth-seeking mechanism that enables placement of the tuber at depth in the soil as a means to avoid predation by surface-foraging native mammals or away from the high temperatures and desiccating conditions during summer dormancy. The 3--5 attenuated roots produced at the junction between the tuber and shoot and produced late in the growing cycle and devoid of mycorrhiza suggest their functional significance may relate to water uptake. Mycorrhizal endophytes are confined to a hypertrophic stem region at the soil surface (collar) subtending the leaf that positions the collar directly in the organically rich zone at the soil surface. This morphology is a unique characteristic of several Australasian orchids in the tribe Diuridae. Mycorrhizal infection occurs rapidly, with maximum colonisation in concert with the onset of breaking rains. Pelotons are restricted to cortical cells, with fully developed pelotons throughout infected tissues within a week or so of soil wetting. Infection occurs as a ‘once-off’ event, with little evidence of secondary infection later in the growth cycle and no evidence of peloton digestion. Some taxa utilise vegetative propagation, often leading to localised clustering as for taxa in the ‘filamentosa’ complex or, extensive clonal mats as found in Caladenia flava and C. latifolia where daughter tubers are produced at the end of extending horizontal outgrowths. For the majority of taxa, plants remain dry-season (summer) dormant from a few months up to 7 months for arid-zone taxa, with shoot emergence from the tuber of temperate species thought to occur in response to a drop in the mean minimum temperature. Pollination biology of Caladenia is apparently through a process of deception, either as food or sexual mimics, with some taxa engaging in self-pollination. Here we review the natural history of Caladenia and acknowledge that much of our understanding is based on assumptions of the biology of terrestrial orchids in general and emphasise areas of research and biological enquiry that will be critical in the development of an effective conservation program for the genus.

scholarly journals Micropropagation of Members of the Cactaceae Subtribe Cactinae

1990 ◽  
Vol 115 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Philip W. Clayton ◽  
John F. Hubstenberger ◽  
Gregory C. Phillips ◽  
S. Ann Butler-Nance
Keyword(s):  
Shoot Proliferation ◽  
Shoot Tip ◽  
Axillary Shoot ◽  
Axillary Shoots ◽  
Axillary Shoot Proliferation ◽  
Shoot Production ◽  
Series Of Experiments ◽  
Basal Media ◽  
Free Media ◽  
Shoot Tip Explants

Micropropagation of 11 rare or endangered cacti species belonging to the subtribe Cactinae was achieved by rooting of proliferated axillary shoots. Shoot tip explants were obtained from seedlings of Escobaria missouriensis D.R. Hunt, E. robbinsorum (Earle) D.R. Hunt, Sclerocactus spinosior (Engelm.) Woodruff & L. Benson, and Toumeya papyracantha (Engelm.) Br. & Rose, and from mature plants of Mammillaria wrightii Engelm., Pediocactus bradyi L. Benson, P. despainii Welsh & Goodrich, P. knowltonii L. Benson, P. paradinei B.W. Benson, P. winkleri Heil, and S. mesae-verdae (Boissevain) L. Benson. Three or four species were used in each of a series of experiments investigating the effects of basal media and auxin and cytokinin types and concentrations on axillary shoot proliferation. Low or no auxin but moderate to high cytokinin concentrations were required for axillary shoot production. All species rooted spontaneously on hormone-free media; however, several species rooted better on media containing auxin. All species were re-established in the greenhouse.

Effect of perennial pasture species on surface soil moisture and early growth and survival of subterranean clover (Trifolium subterraneum L.) seedlings

1997 ◽  
Vol 48 (5) ◽  
pp. 683 ◽  
Author(s):  
B. S. Dear ◽  
P. S. Cocks
Keyword(s):  
Mineral Soil ◽  
Subterranean Clover ◽  
Late Summer ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Annual Grass ◽  
Growth And Survival ◽  
Eastern Australia ◽  
Standing Dead ◽  
Clover Seed

Subterranean clover seedling numbers and growth in swards containing 1 of 5 perennial pasture species [phalaris (Phalaris aquatica) cv. Sirolan, cocksfoot (Dactylis glomerata) cv. Currie, lucerne (Medicago sativa) cv. Aquarius, wallaby grass (Danthonia richardsonii) cv. Taranna, and lovegrass (Eragrostis curvula) cv. Consol] were compared with those in typical annual pastures and pure clover swards in the wheatbelt of eastern Australia. Presence of a perennial species or the volunteer annual grass (Eragrostis cilianensis) increased the rate of drying of the soil surface (0–5 cm) after late February and May rain, compared with subterranean clover swards. Perennials differed in the rate they dried the soil surface, with the more summer-active lucerne and consul lovegrass drying the profile more rapidly than phalaris. The amount of water in the surface 5 cm, 6 days after the rainfall event on 27–28 February, was strongly negatively correlated (r = –0·75, P < 0·01) with the amount of green perennial biomass, but not related to standing dead material or surface residues. Where perennials were present, a smaller proportion (2–4%) of the clover seed pool produced seedlings in response to late summer rain, compared with pure clover swards (18%). A higher proportion of the seed pool produced seedlings (19–36%) following rain in late autumn but there was no difference between species. The more summer-active perennials (cocksfoot, danthonia, and lucerne) markedly depressed the survival of emerged clover seedlings following both germinations. Of the seedlings that emerged in early March, the proportion remaining by 29 March was 57% in phalaris, 21% in lucerne, 13% in danthonia, and 1% in cocksfoot, compared with a 78% increase in seedlings in pure subterranean clover swards. By 15 May, all perennials had <2 clover seedlings/m2 surviving, compared with 37 in the annual pasture and 964 plants/m2 in pure subterranean clover. Following the May germination, the highest proportion of emerged seedlings surviving until 29 May was in the phalaris swards (40%) and least in the cocksfoot and danthonia swards (2–4%). Presence of a perennial or annual grass decreased (P < 0·05) relative water content of clover seedlings on 15 March from 74% in pure clover swards, to 48% in annual pasture, 34% in phalaris, and 29% in lucerne swards. Clover seedlings growing in pure subterranean swards on 15 March (17 days after germinating rain) were 4 times larger than those in lucerne and twice as large as those in either phalaris or annual pasture. Seed size did not differ between treatments, but available mineral soil nitrogen was significantly higher (P < 0·001) in pure subterranean clover swards (32 mg N/g) compared with perennials (3–13 mg N/g). Strategies such as heavy grazing in late summer to reduce green biomass of the perennials or sowing the perennials at lower densities may reduce the adverse effects that perennials have on subterranean clover seedlings in these drier environments.

scholarly journals Impact of Hydrogen Peroxide on Growth and Survival ofListeria MonocytogenesBiofilms

2010 ◽  
Vol 7 (3) ◽  
pp. 1008-1012
Author(s):  
Farhan Zameer ◽  
Shubha Gopal
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Listeria Monocytogenes ◽  
Stationary Phase ◽  
Adaptive Behavior ◽  
Potential Risk ◽  
Growth Cycle ◽  
Food Preservation ◽  
Survival Strategies ◽  
Growth And Survival

The present study aimed to understand the survival strategies adapted byListeria monocytogenesto combat oxidative stress in planktonic and biofilm cells with response to hydrogen peroxide (H2O2). The sensitivity ofL. monocytogenesto H2O2(oxidative stress) was found to vary in growth cycle. Early log phase cells were found to be sensitive to 100 μM H2O2when compared to stationary phase. Biofilm population was found to be resistant to the oxidative stress induced at 4% of H2O2when compared to their planktonic counterpart at 3.5%. This adaptive behavior allows the pathogen to overcome food preservation and safety barriers, which pose a potential risk to human health. The overall results suggest that, H2O2at a concentration of 6% could be used as a potent sanitizer for the elimination of listerial biofilms.

Papaya performance unaffected by lateral shoot pruning

1969 ◽  
Vol 82 (1-2) ◽  
pp. 63-68
Author(s):  
Bryan R. Brunner
Keyword(s):  
Field Experiments ◽  
Germplasm Collection ◽  
Axillary Shoot ◽  
Lateral Shoot ◽  
Axillary Shoots ◽  
Branch Number ◽  
Subsequent Performance ◽  
Date Fruit ◽  
Branch Development ◽  
Lateral Branches

The practice of axillary shoot removal in young (3 to 4 mo) trees of papaya cultivar Puerto Rico 6-65 was examined in field experiments in 1993 and 1995 to determine whether or not subsequent performance is affected. No significant differences were observed between pruned and unpruned plants for flowering date, fruiting date, fruit yield, days to virus infection or virus severity. Significant differences were observed between years for all variables. In an unpruned papaya germplasm collection of 40 genotypes planted in 1993 and 1995, 17 (43%) had no lateral branch development, and 21 (53%) had a mean branch number of less than one per tree. Only two genotypes had a mean branch number greater than one per tree. The pruning of axillary shoots on young papaya plants apparently has no effect on flowering, fruiting or disease control. Most papaya genotypes produce few or no lateral branches when left unpruned. Any lateral branches that are produced can be removed at the time of the first harvest.

Root development in seedlings of ryegrass (Lolium perenne L.) and phalaris (Phalaris aquatica L.) sown onto the soil surface

1982 ◽  
Vol 33 (4) ◽  
pp. 665 ◽  
Author(s):  
PS Cornish
Keyword(s):  
Root Development ◽  
Soil Surface ◽  
Undisturbed Soil ◽  
Growth And Survival ◽  
Small Vessels ◽  
Nodal Roots ◽  
Nodal Root ◽  
Seminal Roots ◽  
Surface Drying ◽  
Axial Resistance

The effects of surface-sowing on root type, number and xylem radius were studied in relation to the seedling growth and survival of ryegrass and phalaris. Under optimal conditions in a growth cabinet, both species produced primary and lateral seminal roots, nodal roots and, in the absence of light, a subcoleoptile internode (s.c.i.). Phalaris had fewer lateral seminal roots and, in this species, internodal roots occurred along the s.c.i. Surface placement per se had no effect on any of the measured parameters of root development, but surface drying prevented nodal root primordia from extending, even when plants were otherwise supplied with water. This effect of surface drying on nodal root development was confirmed in a glasshouse study using undisturbed soil cores (30 by 60 cm) to simulate field conditions. Phalaris was less likely than ryegrass to produce nodal roots after surface sowing. The effective xylem radius (re) of the primary seminal root was 7.9 �m in ryegrass and 11.6 �m in phalaris. Calculations using the Poiseuille equation indicated that the axial resistance to water flow through these roots would greatly restrict seedling water uptake and growth in the absence of other roots. Lateral seminal roots and internodal roots had small vessels which could not significantly reduce the axial resistance to flow. Good seedling water relations in both species therefore depend on early development of the nodal roots which contain large xylem vessels (re > 16 �m). It was concluded that the effect of soil-surface drying on nodal root development was likely to account for some cases of poor vigour and survival of surface-sown grasses.

scholarly journals Soil-Surface Straw Influences Micrometeorological Conditions Affecting Canola Mortality During Nighttime Frosts

2020 ◽  
Vol 12 (11) ◽  
pp. 246
Author(s):  
Samuel Kovaleski ◽  
Arno B. Heldwein ◽  
Genei A. Dalmago ◽  
Jorge A. de Gouvêa ◽  
Gilberto R. da Cunha ◽  
...  
Keyword(s):  
Heat Flux ◽  
Ground Surface ◽  
Soil Surface ◽  
Soil Heat Flux ◽  
Growth Cycle ◽  
The Other ◽  
Net Radiation ◽  
Plant Mortality ◽  
Seedling Mortality ◽  
Micrometeorological Conditions

Our objective was to measure alterations in the micrometeorological conditions surrounding canola seedlings during frost periods, and to quantify seedling mortality as a function of straw distribution on the ground surface. The data was acquired from 15 frosts in 2014. We used four treatments, comprising ground surface without straw (SWS), ground surface entirely straw-covered (SEC), sowing line without straw (SLW), and soil with preexisting surface straw (SES), over three experiments. Net radiation (NR), soil heat flux (G), air (Ta), leaf (Lf), rosette (Tr), and surface temperature (Ts), and plant mortality were evaluated. NR was higher in the SEC treatment and lower in the SLW treatment, whereas G was higher on straw-covered ground; Ts and Ta were lower in the SEC than in the other treatments during the most intense frosts. On 06/19, Tr in the SEC and SLW treatments was -0.66 &deg;C and 0.42 &deg;C, respectively; on 08/14, Lf was -3.62 &deg;C and -2.88 &deg;C in the SEC and SLW treatments, respectively. Plant mortality due to the frost on 06/19 was 30% in the SEC treatment, but 0% in the SLW treatment; the frost of 08/14 caused 33.8% mortality in the SEC treatment and 1.25% in the SLW treatment. This therefore showed that removing straw from the sowing line improved the microclimate around the plants, thus reducing canola mortality at the beginning of the growth cycle, which is when frost events most frequently occur.

scholarly journals Producing Double-stemmed Tomato Seedlings by Cutting Propagation, Pinching, and Plant Bioregulators Application

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 758C-758
Author(s):  
Ki-Yun Jung* ◽  
Bong-Hwa Kang ◽  
Yu-Jin Park ◽  
Jung-Myung Lee
Keyword(s):  
Axillary Shoot ◽  
Stem Cuttings ◽  
Subsequent Growth ◽  
Axillary Shoots ◽  
Tomato Seedlings ◽  
Cotyledonary Nodes ◽  
Whole Plant ◽  
Plug Seedling ◽  
Soil Mix ◽  
Lower Stem

Double-stemmed seedlings (DSS) will be favored by the growers because they can save the expense needed to purchase commercial seedlings. This is also true with grafted tomatoes since the price of grafted tomato seedlings is about 2 times higher than non-grafted ones. The plug seedling growers will also benefit from the increased demand for DSS if the production cost for DSS can be maintained at appropriate level. Two stem cuttings having two expanded leaves were taken from a seedling when the seedling had four expanded leaves and rooted in 32-cell trays filled with commercial soil mix. Lower stem cuttings having first and second leaves produced well-balanced DSS even without any plant bioregulator treatment whereas up upper stem cuttings having third and fourth leaves resulted in single-stem seedlings with very limited outgrowth of axillary shoot from the third node. DSS can be obtained from the decapitated seedling stump by outgrowth of axillary shoots from the cotyledonary nodes, but the quality and uniformity were inferior to other seedlings. Pinching off the tips of seedlings thus leaving three expanded leaves per seedling and application of plant bioregulators to the decapitated seedlings were also effective for producing DDS. Application of thidiazuron (TDZ) in lanolin paste to the second node was most effective even though whole plant spray with TDZ or BA was also partially effective. Subsequent growth characteristics of these seedlings will be further discussed.

scholarly journals Micropropagation of cloudberry (Rubus chamaemorus L.) by initiation of axillary shoots

2014 ◽  
Vol 70 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Barbara Thiem
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Botanical Garden ◽  
Axillary Shoot ◽  
Root Induction ◽  
Ms Medium ◽  
Axillary Shoots ◽  
Rubus Chamaemorus ◽  
Step Procedure

A method for micropropagation of the endangered <em>Rubus chamaemorus</em> L. (<em>Rosaceae</em>) from shoot tips was developed. Murashige and Skoog (MS) medium supplemented with BA and IBA in different concentrations was used for axillary shoot development. The most effective was MS medium containing 0.88 µM BA and 0.49 µM IBA with value of pH = 4.0. Cultures of microshoots (up to 12 shoots from a single explant) developed into regular shoots on the same medium or after transferring them onto MS media with 0.44 µM BA, 0.49 µM IBA and 434 µM SA. The rooting of initiated axillary shoots proved extremely difficult. A two-step procedure for root induction was adopted. Auxin- treated shoots were put to medium devoid of plant growth regulators. Rooted shoots were then transferred to pots and grown in the greenhouse until planted in the ground of the Botanical Garden.

scholarly journals MAX1 and MAX2 control shoot lateral branching in Arabidopsis

Development ◽  
2002 ◽  
Vol 129 (5) ◽  
pp. 1131-1141 ◽  
Author(s):  
Petra Stirnberg ◽  
Karin van de Sande ◽  
H. M. Ottoline Leyser
Keyword(s):  
Positional Cloning ◽  
Leaf Shape ◽  
Shoot Meristem ◽  
Axillary Shoot ◽  
Axillary Meristem ◽  
Axillary Shoots ◽  
Recessive Mutations ◽  
Lateral Shoots ◽  
Plant Shoots ◽  
Shoot Meristems

Plant shoots elaborate their adult form by selective control over the growth of both their primary shoot apical meristem and their axillary shoot meristems. We describe recessive mutations at two loci in Arabidopsis, MAX1 and MAX2, that affect the selective repression of axillary shoots. All the first order (but not higher order) axillary shoots initiated by mutant plants remain active, resulting in bushier shoots than those of wild type. In vegetative plants where axillary shoots develop in a basal to apical sequence, the mutations do not clearly alter node distance, from the shoot apex, at which axillary shoot meristems initiate but shorten the distance at which the first axillary leaf primordium is produced by the axillary shoot meristem. A small number of mutant axillary shoot meristems is enlarged and, later in development, a low proportion of mutant lateral shoots is fasciated. Together, this suggests that MAX1 and MAX2 do not control the timing of axillary meristem initiation but repress primordia formation by the axillary meristem. In addition to shoot branching, mutations at both loci affect leaf shape. The mutations at MAX2 cause increased hypocotyl and petiole elongation in light-grown seedlings. Positional cloning identifies MAX2 as a member of the F-box leucine-rich repeat family of proteins. MAX2 is identical to ORE9, a proposed regulator of leaf senescence (Woo, H. R., Chung, K. M., Park, J.-H., Oh, S. A., Ahn, T., Hong, S. H., Jang, S. K. and Nam, H. G. (2001) Plant Cell13, 1779-1790). Our results suggest that selective repression of axillary shoots involves ubiquitin-mediated degradation of as yet unidentified proteins that activate axillary growth.

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