scholarly journals Drought Response of Young Apple Trees on Three Rootstocks: Growth and Development

1997 ◽  
Vol 122 (1) ◽  
pp. 14-19 ◽  
Author(s):  
R. Thomas Fernandez ◽  
Ronald L. Perry ◽  
James A. Flore

`Imperial Gala' apple (Malus domestica Borkh.) trees, trained to two shoots, on M.9 EMLA, MM.111, and Mark rootstocks were subjected to two drought-stress and recovery periods in a rainshelter. Leaf growth rate, leaf area, leaf emergence, shoot length, and trunk cross-sectional area were measured during each stress and recovery period. Leaf growth rate was reduced during both stress periods but most consistently during the second drought stress. Length of the less-vigorous shoot was reduced most consistently due to drought stress but did not recover upon irrigation. Leaf emergence and trunk cross-sectional area increment were inconsistent in response to stress. Tree growth was reduced by drought stress to the greatest extent for trees on Mark, with MM.111 intermediate and M.9 EMLA least affected. At termination, the plants were separated into roots, current-season shoot growth, previous-season shoot growth, and rootstock, and dry weights were measured. Dry weights confirmed the growth measurements taken during the experiment with a 16%, 27%, and 34% reduction in total plant dry weight for drought-stressed trees on M.9 EMLA, MM.111, and Mark, respectively, compared to corresponding controls. It was concluded that Mark was the most sensitive of the three rootstocks followed by MM.111; M.9 EMLA was the most drought resistant.

2019 ◽  
Vol 29 (2) ◽  
pp. 210-212
Author(s):  
Haijun Zhu ◽  
Eric T. Stafne

Paclobutrazol (PBZ) was applied to 6-year-old pecan (Carya illinoinensis) trees as a basal trunk drench (0, 30, 90, and 150 mg·cm−2 trunk cross-sectional area) in Dec. 2012. Terminal shoot growth was retarded for 1 year after a single application of PBZ. The total number of current season shoots showed a significant increase with 30- and 90-mg·cm−2 PBZ treatments. After PBZ application at 30, 60, and 90 mg·cm−2, the percentage of very short shoots (<5 cm) was 32.3%, 36.3%, and 32.3%, respectively, compared with 22.4% on control trees; the percentage of short shoots (5–15 cm) increased to 36.0%, 38.1%, and 43.5%, respectively. The percent of long shoots (>30 cm) was decreased to 7.4%, 5.1%, and 7.6%, respectively, after PBZ application, compared with 18.7% with control. Shoots varying from 5 to 30 cm in length accounted for at least 63.3% of all pistillate inflorescences the following spring.


AoB Plants ◽  
2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Jun Sun ◽  
Mantang Wang ◽  
Min Lyu ◽  
Karl J Niklas ◽  
Quanlin Zhong ◽  
...  

Abstract The trade-off between leaf number and individual leaf size on current-year shoots (twigs) is crucial to light interception and thus net carbon gain. However, a theoretical basis for understanding this trade-off remains elusive. Here, we argue that this trade-off emerges directly from the relationship between annual growth in leaf and stem mass, a hypothesis that predicts that maximum individual leaf size (i.e. leaf mass, Mmax, or leaf area, Amax) will scale negatively and isometrically with leafing intensity (i.e. leaf number per unit stem mass, per unit stem volume or per stem cross-sectional area). We tested this hypothesis by analysing the twigs of 64 species inhabiting three different forest communities along an elevation gradient using standardized major axis (SMA) analyses. Across species, maximum individual leaf size (Mmax, Amax) scaled isometrically with respect to leafing intensity; the scaling constants between maximum leaf size and leafing intensity (based on stem cross-sectional area) differed significantly among the three forests. Therefore, our hypothesis successfully predicts a scaling relationship between maximum individual leaf size and leafing intensity, and provides a general explanation for the leaf size-number trade-off as a consequence of mechanical-hydraulic constraints on stem and leaf growth per year.


2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Jesse J. Rohr ◽  
Stuart Sater ◽  
Austin M. Sass ◽  
Karina Marshall-Goebel ◽  
Robert J. Ploutz-Snyder ◽  
...  

Abstract A subset of long-duration spaceflight astronauts have experienced ophthalmic abnormalities, collectively termed spaceflight-associated neuro-ocular syndrome (SANS). Little is understood about the pathophysiology of SANS; however, microgravity-induced alterations in intracranial pressure (ICP) due to headward fluid shifts is the primary hypothesized contributor. In particular, potential changes in optic nerve (ON) tortuosity and ON sheath (ONS) distension may indicate altered cerebrospinal fluid dynamics during weightlessness. The present longitudinal study aims to provide a quantitative analysis of ON and ONS cross-sectional areas, and ON deviation, an indication of tortuosity, before and after spaceflight. Ten astronauts undergoing ~6-month missions on the International Space Station (ISS) underwent high-resolution magnetic resonance imaging (MRI) preflight and at five recovery time points extending to 1 year after return from the ISS. The mean changes in ON deviation, ON cross-sectional area, and ONS cross-sectional area immediately post flight were −0.14 mm (95% CI: −0.36 to 0.08, Bonferroni-adjusted P = 1.00), 0.13 mm2 (95% CI −0.66 to 0.91, Bonferroni-adjusted P = 1.00), and −0.22 mm2 (95% CI: −1.78 to 1.34, Bonferroni-adjusted P = 1.00), respectively, and remained consistent during the recovery period. Terrestrially, ONS distension is associated with increased ICP; therefore, these results suggest that, on average, ICP was not pathologically elevated immediately after spaceflight. However, a subject diagnosed with optic disc edema (Frisen Grade 1, right eye) displayed increased ONS area post flight, although this increase is relatively small compared to clinical populations with increased ICP. Advanced quantitative MRI-based assessment of the ON and ONS could help our understanding of SANS and the role of ICP.


1990 ◽  
Vol 68 (2) ◽  
pp. 533-539 ◽  
Author(s):  
C. E. Kasper ◽  
T. P. White ◽  
L. C. Maxwell

The objectives were to study morphological adaptations of soleus muscle to decreased loading induced by hindlimb suspension and the effect of run training during the subsequent recovery period. Adult female Wistar rats were kept for 28 days with hindlimbs suspended. For the next 28 days, rats were assigned to a cage-sedentary or daily running group. Compared with control soleus muscles, 28 days of hindlimb suspension reduced the mass and fiber cross-sectional area to 58 and 53% of control values, respectively, and decreased type I fibers from 92 +/- 2 to 81 +/- 2%. During recovery, clusters of damaged fibers were observed in the soleus muscle, and this observation was more pronounced in trained animals. Type IIc fibers appeared transiently during recovery, and their presence was exacerbated with training, as IIc fibers increased to approximately 20% of the total by day 14 of recovery and were no longer evident at day 28. Although muscle wet mass does not differ as a result of mode of recovery at day 14, training transiently decreased the overall fiber area compared with sedentary recovery at this point. By day 28 of recovery the morphological characteristics of soleus muscle in the trained group did not differ from control muscle, whereas in the sedentary group muscle mass and overall fiber cross-sectional area were approximately 14% less than control values.


2001 ◽  
Vol 28 (2) ◽  
pp. 165 ◽  
Author(s):  
Yuncai Hu ◽  
Urs Schmidhalter

Expansion and dry weight (DW) of wheat leaves are spatially distributed along the axis and affected by salinity. The objective of this study was to evaluate the effect of salinity on the spatial distribution of cellular cross-sectional area and DW in the elongating and mature leaf zones of leaf 4 of the main stem of spring wheat (Triticum aestivum L. cv. Lona) during its linear growth phase. Plants were grown in illitic–chloritic silt loam with 0 and 120 mM NaCl in a growth chamber. Cellular cross-sectional area and DW contents of leaves were determined on the 5–20-mm scale along the leaf axis. Spatial distribution of cellular cross-sectional area changed slightly with distance within the elongation zone in both treatments. The cellular cross-sectional area of the leaf at 120 mM NaCl was reduced by 32% at 5 mm, as compared with about 36% averaged from the region between 5 and 30 mm from the leaf base, indicating that the reduction in the cellular cross-sectional area by salinity occurred mainly at the leaf base when the leaf initiates. A slight decrease in the DW per leaf length at a given location in the elongation zone may be due to the strongly decreased cellular cross-sectional area by salinity. This suggests that the limitation of leaf growth by salinity may be due mainly to the effect of salinity on leaf expansion, but not due to the effect on the synthesis of dry matter.


2003 ◽  
Vol 128 (4) ◽  
pp. 463-471 ◽  
Author(s):  
Antonio Weibel ◽  
R. Scott Johnson ◽  
Theodore M. DeJong

Vegetative growth of two peach (Prunus persica L. Batsch) cultivars Flavorcrest and Loadel growing on six different rootstocks (`Nemaguard', `Hiawatha', K-146-43, K-146-44, P-30-135, and K-119-50) was analyzed during the third season of growth in an experimental orchard at the University of California Kearney Agricultural Center near Parlier, California. Seasonal trunk cross-sectional area, shoot and internode growth, diurnal stem extension growth rate and summer and dormant pruning weights were measured to determine extent of size-control imparted by the experimental rootstocks compared to the trees on the `Nemaguard' control and to characterize the nature of the sizecontrolling response. Trunk cross-sectional area growth of trees on the two smallest rootstocks (K-146-43 and K-146-44) was only 25% to 37% of the growth of trees on `Nemaguard', while trees on the other three rootstocks provided an intermediate level of size control. Generally, the seasonal patterns of shoot growth did not vary substantially among trees on the different rootstocks, but average shoot and internode lengths did correspond with tree size. Vigorous watersprout growth was decreased by more than 80% in the trees on the least vigorous rootstocks compared to trees on `Nemaguard' resulting in major reductions in the extent of summer and winter pruning weights. Variations in vegetative shoot growth appeared to correspond to variations in daily shoot extension growth rates but more research is needed to explore these relationships.


HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 219-221 ◽  
Author(s):  
G.E. Boyhan ◽  
J.D. Norton ◽  
J.A. Pitts

The dwarfing characteristics of St. Julien and Pixy rootstocks, measured by shoot growth, were evident with `AU-Amber' and `AU-Producer' plum (Prunus salicina Lindl.) scions. Dwarfing did not occur with `AU-Rubrum'. Trunk cross-sectional area (TCA) was reduced with `AU-Amber', `AU-Producer', and `AU-Rubrum' scions on St. Julien and Pixy rootstocks. After 3 years, tree survival was 94% for Lovell; 89%, Halford; 57%, Nemaguard; 75%, Nemared; 83%, St. Julien; and 47%, Pixy. Tree survivability was significantly lower on Nemaguard and Pixy rootstocks than on Lovell and Halford. Multiple regression of total shoot growth, TCA, and survivability against foliar nutrient content resulted in the following significant equations: 0.460Mg - 0.210Mn, 0.236B - 0.487Mn, and 0.359N + 0.398Ca - 0.267P - 0.360Fe for each, respectively. Growth, survivability, and foliar nutrient content are significantly affected by rootstock in plum production.


2020 ◽  
Author(s):  
Hannah M. Schneider ◽  
Jennifer T. Yang ◽  
Kathleen M. Brown ◽  
Jonathan P. Lynch

AbstractUnder nitrogen limitation, plants increase resource allocation to root growth relative to shoot growth. The utility of various root architectural and anatomical phenotypes for nitrogen acquisition are not well understood. Nodal root number and root cross-sectional area were evaluated in maize in field and greenhouse environments. Nodal root number and root cross-sectional area were inversely correlated under both high and low nitrogen conditions. Attenuated emergence of root nodes, as opposed to differences in the number of axial roots per node, was associated with substantially reduced root number. Greater root cross-sectional area was associated with a greater stele area and number of cortical cell files. Genotypes that produced few, thick nodal roots rather than many, thin nodal roots had deeper rooting and better shoot growth in low nitrogen environments. Fewer nodal roots offset the respiratory and nitrogen costs of thicker diameter roots, since total nodal root respiration and nitrogen content was similar for genotypes with many, thin and few, thick nodal roots. We propose that few, thick nodal roots may enable greater capture of deep soil nitrogen and improve plant performance under nitrogen stress. The interaction between an architectural and anatomical trait may be an important strategy for nitrogen acquisition. Understanding trait interactions among different root nodes has important implications in for improving crop nutrient uptake and stress tolerance.


Author(s):  
T.I. Kuznetsova

The aim of the paper is to study the effect of long-term feeding with finely ground food on the dynamics of cytometric hepatocyte parameters in white rats in postnatal ontogenesis. Materials and Methods. On the 21st day of postnatal ontogenesis, 100 male white rats were divided into a control group and two experimental groups (experiment 1 and experiment 2). The animals of the control group were fed with natural food, while the animals of the experimental groups similar food (in terms of quality and quantity), but after careful mechanical grinding. To assess the reversibility of the homogenized food feeding, animals of experimental group 2 were fed natural food, as the control animals (days 120–240). The authors studied the liver, using cell morphometry of standard histological staining. They measured cross-sectional area of the nuclei and hepatocyte cytoplasm, calculated nuclear-cytoplasmic ratio, and counted the number of hepatocytes on the standard cross-sectional area, including binuclear hepatocytes. Results. It was revealed that long-term consumption of homogenized food affects the postnatal morphogenesis of the liver parenchyma. From the 21st to the 120th day, the growth rate of hepatocytes and the number of binuclear cells in the experimental animals exceeded those of the control animals, and from the 120th up to the 240th day, the growth rate of hepatocytes in the experimental animals was significantly inferior to that of the control animals. As a result, the number of cells per standard cutting area increased. In case of transition to normal food with natural mechanical properties (120th–240th days of postnatal ontogenesis) there was a tendency to the restoration of cytometric hepatocyte parameters. However, the authors did not observe complete recovery. Keywords: liver, hepatocyte, homogenized food. Цель работы – изучить влияние длительного питания мелко измельченной пищей на динамику цитометрических параметров гепатоцитов белых крыс в постнатальном онтогенезе. Материалы и методы. На 21-е сут постнатального онтогенеза 100 самцов белых крыс были разделены на контрольную и две опытные группы (опыт I и опыт II). Животных контрольной группы содержали на естественном для грызунов корме, а животные опытных групп получали аналогичную по качественному и количественному составу пищу, но после тщательного механического измельчения. Для оценки обратимости воздействия питания диспергированной пищей животных II опытной группы со 120-х по 240-е сут переводили на питание кормом контрольных животных. Исследовали участки печени, морфометрию клеток которой проводили на стандартно окрашенных гистологических срезах. Измеряли площадь сечения ядер и цитоплазмы гепатоцитов, вычисляли ядерно-цитоплазматическое отношение, на стандартной площади среза подсчитывали количество гепатоцитов, в т.ч. двуядерных. Результаты. Выявлено, что длительное потребление диспергированной пищи оказывает воздействие на постнатальный морфогенез паренхимы печени. С 21-х по 120-е сут интенсивность роста гепатоцитов и количество двуядерных клеток опытных животных превышает таковые значения контрольных, а с 120-х по 240-е сут интенсивность роста гепатоцитов опытных животных существенно уступает показателям контрольных животных, вследствие чего количество клеток на стандартную площадь среза увеличивается. При переходе к питанию пищей с естественными механическими свойствами со 120-х по 240-е сут постнатального онтогенеза наблюдается тенденция к восстановлению цитометрических параметров гепатоцитов, однако полного восстановления не происходит. Ключевые слова: печень, гепатоцит, диспергированная пища.


HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 431d-431
Author(s):  
J.D. Norton ◽  
G.E. Boyhan ◽  
J.A. Pitts

The dwarfing characteristics of St. Julien and Pixy rootstocks as measured by shoot growth and trunk cross-sectional area (TCSA) was evident. Tree survival was significantly reduced after 3 years on Nemaguard and Pixy rootstocks. None of the elements measured by foliar nutrient analysis were below the minimum for plums; however, significant multiple regression equations for total shoot growth, TCSA, and survivability were evident with R2 of ≈0.30 in all three cases.


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