Physiological adaptations of Hymenachne amplexicaulis to flooding

1999 ◽  
Vol 39 (4) ◽  
pp. 429 ◽  
Author(s):  
H. Kibbler ◽  
L. M. Bahnisch
Keyword(s):  
Native Species ◽  
Adventitious Roots ◽  
Aerenchyma Formation ◽  
Galvanised Steel ◽  
Physiological Adaptations ◽  
Steel Tanks ◽  
Series Of Experiments ◽  
Rapid Elongation ◽  
Root Tissues ◽  
Stem Leaf

The introduced grass Hymenachne amplexicaulis has been established for use in ponded pastures in Central Queensland. However, its ability to out compete native species and invade wetlands makes it a potential weed. To determine the characteristics that make it a successful ponded pasture species, the adaptation of H. amplexicaulis to flooding has been investigated. The growth and development of H. amplexicaulis under flooded and non-flooded conditions was compared in a series of experiments carried out in three 2 m high galvanised steel tanks. Leaf, stem and root sections were taken to determine the timing and extent of aerenchyma formation. The effect of flooding on the pattern and distribution of growth was also determined. Hymenachne amplexicaulis is adapted to flooding because it has the capacity for rapid elongation of the stem and the formation of adventitious roots. Aerenchyma was present in stem, leaf and root tissues in both flooded and non-flooded plants. The aerenchyma would provide buoyancy as well as aiding the circulation of gases. When the plants were flooded, submerged leaves senesced rapidly and the previously exposed, but now submerged nodes produced adventitious roots. Under flooding, the growth of leaves increased at the expense of the roots, presumably maintaining the effective photosynthetic leaf area. The implications and limitations of these adaptations are discussed.

scholarly journals Longitudinal Pattern of Aerenchyma Formation Using the Ti-Gompertz Model in Rice Adventitious Roots

2021 ◽  
Vol 12 ◽  
Author(s):  
Yun Chen ◽  
Guoming Li ◽  
Buhong Zhao ◽  
Yajun Zhang ◽  
Kun Liu ◽  
...  
Keyword(s):  
Adventitious Roots ◽  
Goodness Of Fit ◽  
Gompertz Model ◽  
Root Apex ◽  
Information Criterion ◽  
Ordinary Least Squares ◽  
Parameter Estimates ◽  
Aerenchyma Formation ◽  
Root Aerenchyma ◽  
Longitudinal Pattern

The longitudinal pattern of root aerenchyma formation of its relationship with the function of adventitious roots in rice remains unclear. In this study, the percentage of the aerenchyma area to the cross-sectional area (i.e., aerenchyma percentage) was fit with four non-linear models, namely, W0-Gompertz, Ti-Gompertz, logistic, and von Bertalanffy. Goodness-of-fit criteria such as the R2, the Akaike information criterion (AIC), and the Bayesian information criterion (BIC) were used to select the model. The bias of the parameters was evaluated using the difference between the ordinary least squares-based parameter estimates and the mean of 1,000 bootstrap-based parameter estimates and the symmetry of the distributions of these parameters. The results showed that the Ti-Gompertz model, which had a high goodness-of-fit with an R2 close to 1, lower AIC and BIC values, parameter estimates close to being unbiased, and good linear approximation, provided the best fit for the longitude pattern of rice aerenchyma formation with different root lengths among the competing models. Using the second- and third-order derivatives according to the distance from the root apex, the critical points of Ti-Gompertz were calculated. The rapid stage for aerenchyma formation was from the maximum acceleration point (1.38–1.76 cm from the root apex) to the maximum deceleration point (3.13–4.19 cm from the root apex). In this stage, the aerenchyma percentage increased by 5.3–15.7% per cm, suggesting that the cortical cells tended to die rapidly for the aerenchyma formation rather than for the respiration cost during this stage. Meanwhile, the volume of the aerenchyma of the entire roots could be computed using the integral function of the Ti-Gompertz model. We proposed that the longitudinal pattern of root aerenchyma formation modeled by the Ti-Gompertz model helped to deeply understand the relationship between the anatomical traits and physiological function in rice adventitious roots.

scholarly journals Histological Observation of Primary and Secondary Aerenchyma Formation in Adventitious Roots of Syzygium kunstleri (King) Bahadur and R.C.Gaur Grown in Hypoxic Medium

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 137 ◽  
Author(s):  
Hong-Duck Sou ◽  
Masaya Masumori ◽  
Hiroyuki Kurokochi ◽  
Takeshi Tange
Keyword(s):  
Formation Process ◽  
Rainy Season ◽  
Adventitious Roots ◽  
Root Tip ◽  
Histological Observation ◽  
Root Tips ◽  
Aerenchyma Formation

Trees growing in wetlands develop adventitious roots from the trunk during the rainy season and adapt to the flooded environment by forming primary (schizogenous or lysigenous) and secondary aerenchyma in the roots. Therefore, it is necessary to clarify the formation process of each type of aerenchyma in these adventitious roots. In this study, saplings of Syzygium kunstleri (King) Bahadur and R.C.Gaur were grown under four different treatments, and a total of 12 adventitious roots generated from trunks were used to clarify the distribution of each aerenchyma type in the roots using light or epi-florescence microscopy. Schizogenous aerenchyma was observed in the root tips where the root color was white or light brown, whereas lysigenous aerenchyma was found at some distance from the root tip where the root color gradually changed from light to dark brown. The secondary aerenchyma and periderm were observed in dark brown parts near the root base. None or only one layer of phellem cells was detected in the white roots near the root tip, but dark brown roots near the root base had at least three layers of phellem cells. Considering these results, oxygen transportation may occur between primary and secondary aerenchyma at the point where two or more layers of phellem cells are formed.

scholarly journals Aerenchyma Formation in Adventitious Roots of Tall Fescue and Cocksfoot under Waterlogged Conditions

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2487
Author(s):  
Nguyen Thi Mui ◽  
Meixue Zhou ◽  
David Parsons ◽  
Rowan William Smith
Keyword(s):  
Tall Fescue ◽  
Festuca Arundinacea ◽  
Adventitious Root ◽  
Adventitious Roots ◽  
Screening Program ◽  
Adventitious Root Formation ◽  
Shoot Biomass ◽  
Waterlogging Tolerance ◽  
Aerenchyma Formation ◽  
Dactylis Glomerata L

The formation of aerenchyma in adventitious roots is one of the most crucial adaptive traits for waterlogging tolerance in plants. Pasture grasses, like other crops, can be affected by waterlogging, and there is scope to improve tolerance through breeding. In this study, two summer-active cocksfoot (Dactylis glomerata L.) cultivars, Lazuly and Porto, and two summer-active tall fescue (Lolium arundinaceum Schreb., syn. Festuca arundinacea Schreb.) cultivars, Hummer and Quantum II MaxP, were selected to investigate the effects of waterlogging on root growth and morphological change. Cultivars were subjected to four periods of waterlogging treatments (7, 14, 21 and 28 days), while comparable plants were kept under free drained control conditions. The experiment was arranged as a split–split plot design, with waterlogging treatments (waterlogged, control) considered as main plots, time periods (days of waterlogging) as subplots and cultivars as sub-subplots. Plants began to show signs of waterlogging stress 14–21 days after the onset of waterlogging treatments. There were no significant differences in shoot biomass between the waterlogged and control plants of any cultivar. However, waterlogging significantly reduced root dry matter in all cultivars, with greater reduction in cocksfoot (56%) than in tall fescue (38%). Waterlogging also led to increased adventitious root and aerenchyma formation in both species. Cocksfoot cultivars showed a greater increase in adventitious roots, while tall fescue cultivars had a greater proportion of aerenchyma. Both cultivars within each species showed similar responses to waterlogging treatments. However, an extended screening program is needed to identify whether there are varietal differences within species, which could be used to discover genes related to aerenchyma or adventitious root formation (waterlogging tolerance) for use in breeding programs.

Flooding tolerance in five populations of Lotus glaber Mill. (Syn. Lotus tenuis Waldst. et. Kit.)

1999 ◽  
Vol 50 (4) ◽  
pp. 555 ◽  
Author(s):  
O. R. Vignolio ◽  
O. N. Fernández ◽  
N. O. Maceira
Keyword(s):  
Low Temperatures ◽  
Root Biomass ◽  
Adventitious Roots ◽  
Positive Relationship ◽  
Flooding Tolerance ◽  
Ecological Studies ◽  
Flooding Pampa ◽  
Morphological Adaptations ◽  
Stem Leaf ◽  
Lotus Glaber

Lotus glaber Mill. is a herbaceous legume, tolerant to flooding, that in a few decades has colonised the Flooding Pampa grasslands, an extensive wetland of 90 000 km in central-east Argentina. In this study, the growth and nodulation of flooded plants in 5 local populations were evaluated. Thirty-day-old seedlings, grown in pots, were flooded outdoors during 4 months. Stem, leaf, and root biomass, as well as the number of nodules per plant, were lower in flooded plants than in non-flooded ones. In flooded plants, the submerged portions of stems were hypertrophied and populations differed in the proportion of plants with adventitious roots. Flood tolerance was significantly related to the proportion of plants with adventitious roots in stems of each population. A positive relationship was shown between the proportion of plants with adventitious root and number of nodules per plant. The plants were also tolerant of low temperatures and ice-sheeting of water. These results underline the importance of morphological adaptations related to the maintenance of plant functionality under flooding conditions. The results provide evidence of the existence of characters related to flooding tolerance, which should be taken into account in ecological studies and agronomic selection programs

Ethylene and programmed cell death in plants

Botany ◽  
2009 ◽  
Vol 87 (8) ◽  
pp. 757-769 ◽  
Author(s):  
Christopher P. Trobacher
Keyword(s):  
Signal Transduction ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Adventitious Roots ◽  
Future Research ◽  
Aerenchyma Formation ◽  
Gaseous Hydrocarbon ◽  
Reproductive Structures ◽  
Ethylene Signalling ◽  
Ethylene Signal

Plants produce and utilize the gaseous hydrocarbon ethylene as a phytohormone throughout their life cycle. Ethylene is notoriously associated with fruit ripening and this aspect of its biology, along with its biosynthesis and mechanisms of signal transduction, has received a great deal of study. Many plants also employ ethylene signalling during instances of programmed cell death (PCD), including aerenchyma formation, epidermal PCD above emerging adventitious roots, senescence of petals, leaves, and reproductive structures, and endosperm death in developing cereal seeds. Ethylene-signalling during PCD is both spatially and temporally regulated, and is selective in that it induces PCD only in sensitized cells or tissues. This review examines instances of ethylene-regulated plant PCD, proposes a general model, and suggests avenues for future research that might improve our understanding of both PCD and ethylene signal transduction.

scholarly journals Position of Source Leaf Affects Translocation and Distribution of C14 Photo-Assimilates in Tomato

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 759C-759
Author(s):  
Sang Gyu Lee* ◽  
Chiwon W. Lee
Keyword(s):  
Lycopersicon Esculentum ◽  
Leaf Position ◽  
Plant Parts ◽  
Root Tissues ◽  
The Relationship ◽  
Stem Leaf ◽  
Different Parts

The relationship between source leaf position and the photo-assimilate translocation and distribution was characterized for tomato (Lycopersicon esculentum Mill.) grown in the greenhouse. Three different positions of source leaf on the stem (first node above or below the first fruit cluster and fifth node above the first fruit cluster) were tested for their influence on 14CO2 assimilation and transfer to different parts of the plant. The leaves at the fifth node above the first fruit cluster transferred the highest (57%) proportion of C14 to other plant parts, followed by leaves borne on the first node below the first fruit cluster (50%), and the first node above the first fruit cluster (39%). In all treatments, fruits served as the strongest sink for C14, followed by stem, leaf, and root tissues. The leaf borne on the fifth node above the first fruit cluster transferred the largest amount of C14 to the second fruit cluster.

scholarly journals Edmund Goodwyn and the first description of diving bradycardia

2017 ◽  
Vol 123 (2) ◽  
pp. 275-277 ◽  
Author(s):  
Jose L. Vega
Keyword(s):  
Heart Rate ◽  
Water Immersion ◽  
Historical Context ◽  
Physiological Adaptations ◽  
University Of Edinburgh ◽  
Series Of Experiments ◽  
Original Observation ◽  
The University ◽  
Response To Water ◽  
British Physician

Diving bradycardia is a primordial oxygen-conserving reflex by which the heart rate of air-breathing vertebrates, including humans, slows down in response to water immersion. Its discovery is attributed to Paul Bert, whose seminal observation was published in 1870 as part of a series of experiments that examined physiological adaptations to asphyxia in ducks and other animals. However, Edmund Goodwyn, a British physician who studied medicine at the University of Edinburgh, had already described this reflex in his doctoral thesis, which was originally published in Latin in 1786 and again in English in 1788. Ironically, even though Goodwyn's work has yet to be recognized in the diving physiology literature, it was referenced in the very publication that contains Bert's original observation. Thus this article brings Goodwyn’s work and its historical context to light and argues that he should be credited with the first description of diving bradycardia.

scholarly journals Cortical Aerenchyma Formation in Hypocotyl and Adventitious Roots of Luffa cylindrica Subjected to Soil Flooding

2007 ◽  
Vol 100 (7) ◽  
pp. 1431-1439 ◽  
Author(s):  
Satoshi Shimamura ◽  
Satoshi Yoshida ◽  
Toshihiro Mochizuki
Keyword(s):  
Adventitious Roots ◽  
Luffa Cylindrica ◽  
Aerenchyma Formation ◽  
Soil Flooding
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