Sudden and sustained response of Acacia koa crop trees to crown release in stagnant stands

2008 ◽  
Vol 38 (4) ◽  
pp. 656-666 ◽  
Author(s):  
Patrick J. Baker ◽  
Andrew P. Robinson ◽  
John J. Ewel
Keyword(s):  
Water Stress ◽  
Leaf Area ◽  
Growth Response ◽  
Water Status ◽  
Control Treatment ◽  
Acacia Koa ◽  
Diameter Increment ◽  
Breast Height ◽  
Second Growth ◽  
And Control

We examined the growth response of Acacia koa Gray (koa) in dense (10 000 trees/ha), ~25-year-old, second-growth stands on Hawai‘i to crown release (thinning) and grass control. Koa diameter increment increased within 2 months of thinning across the range of residual densities (200–900 trees/ha). After 3 years, diameter increment in the most intense thinning treatment was 180% greater than in the control treatment (1.4 vs. 0.5 cm/year); in the least intense thinning treatment diameter increment was 100% greater than the control (1.0 vs. 0.5 cm/year). Koa’s growth response was independent of all measures of tree size (diameter at breast height, height, and leaf area) across the range of tree sizes sampled. A grass control treatment to determine if reduced competition for soil water would improve koa growth showed no improvement in growth response. Koa phyllode δ13C values, which represent an integrated measure of tree water status, showed no evidence of tree water stress (mean δ13C = –28.3‰) and were not significantly different between the grass removal and control treatments. These results demonstrate that koa is capable of responding quickly and positively to crown release despite years of suppressed growth and suggest that landowners interested in managing koa forests may have considerable flexibility in the timing and application of thinning treatments to koa stands.

Stomatal conductance and growth of five Alnusglutinosa clones in response to controlled water stress

1988 ◽  
Vol 18 (4) ◽  
pp. 421-426 ◽  
Author(s):  
T. C. Hennessey ◽  
E. M. Lorenzi ◽  
R. W. McNew
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Drought Tolerance ◽  
Leaf Area ◽  
Water Status ◽  
Height Growth ◽  
Plant Water ◽  
Black Alder ◽  
Severe Water Stress ◽  
Progressive Water Stress

An experiment to quantify the response of unnodulated, fertilized European black alder (Alnusglutinosa (L.) Gaertn.) seedlings to progressive water stress showed contrasting drought tolerance among five clones, using stomatal conductance, leaf area, and height as indices of drought sensitivity. In particular, one rapidly growing clone (AG 8022-14) showed the ability to moderate changes in water stress more efficiently than the more slowly growing clones. After 30 days of moderate levels of water stress, clones that had higher stomatal conductance also had greater leaf area and height growth. Leaf area and height were both sensitive to plant water status, although no threshold of stress associated with a cessation of leaf area or height expansion was found even though stomatal conductance decreased to 0.05 cm s−1 under severe water stress.

scholarly journals The Effect of a Hydrophilic Polymer on Plant Water Status and survival of Transplanted Pine Seedlings

1995 ◽  
Vol 5 (2) ◽  
pp. 141-143 ◽  
Author(s):  
R. Savé M. Pery ◽  
O. Marfà ◽  
L. Serrano
Keyword(s):  
Seedling Survival ◽  
Water Status ◽  
Control Treatment ◽  
Hydrophilic Polymer ◽  
Stress Injury ◽  
Pine Seedlings ◽  
Field Assay ◽  
Greenhouse Assay ◽  
And Control ◽  
Polymer Treatments

Two experiments were conducted to assess the ability of a water-absorbing synthetic polymer to reduce water stress injury of seedlings of Pinus pinea L. under greenhouse and field conditions. In both experiments, two rates of hydrated hydrogel, corresponding to 200 and 400 cm3 of stored water, and a control treatment without hydrophilic polymer were tested. Survival periods for the pine seedlings were 1.4 and 2.0 times longer for the 200- and 400-cm3 treatments, respectively, than for a control treatment in a greenhouse assay. In the field assay, only differences in seedling survival between both hydrogel treatments and control were measured. Leaf water potential values of control plants were significantly lower than hydrated polymer treatments in both experiments. From these results, we conclude that the use of hydrophilic polymers may be an important method of increasing the success of reforestation in semiarid regions.

scholarly journals Categorization of the water status of rice inoculated with arbuscular mycorrhizae and with water deficit

2021 ◽  
pp. 339-355
Author(s):  
Michel Ruiz Sánchez ◽  
Juan Adriano Cabrera Rodríguez ◽  
José M. Del'Anico Rodríguez ◽  
Yaumara Muñoz Hernández ◽  
Ricardo Aroca Álvarez ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Mycorrhizal Fungi ◽  
Water Status ◽  
Light Stress ◽  
Arbuscular Mycorrhizal ◽  
Arbuscular Mycorrhizal Symbiosis ◽  
Control Treatment ◽  
Mycorrhizal Symbiosis ◽  
Rice Plants

Introduction. The water deficit negatively affects rice plants and limits their productivity. Arbuscular mycorrhizal symbiosis has been shown to improve rice productivity in drought conditions. Objective. To propose a new categorization for the state of water stress of rice plants inoculated (AM) or not with arbuscular mycorrhizal fungi (nonAM) and exposed to water deficit (D) during the vegetative phase. Materials and methods. The experiment was carried out under controlled greenhouse conditions during the years 2009 and 2010 at the Zaidín Experimental Station, Granada, Spain. The rice transplantation was carried out fourteen days after germination to pots with a 5 cm water sheet and at 30, 40, or 50 days after transplantation (DAT) they were subjected to water deficit during a period of 15 days, at which time the water sheet was restored. The control treatment was maintained throughout the cycle under flood conditions (ww). Evaluations were performed at 45, 55, 65 DAT and after recovery at 122 DAT. The harvest was carried out at 147 DAT. Results. The reduction in water supply demonstrated water stress in the plants, manifested by the decrease in the water potential of the leaves. Arbuscular mycorrhizal symbiosis always favored the water status of the plant. Four categories of water status of plants were proposed taking into account water potentials and agricultural yield: no stress (≥-0.67 MPa); light stress (<-0.67 to -1.20 MPa); moderate stress (<-1.20 to -1.60 MPa), and severe stress (<-1.60 MPa). Conclusion. The categorization of stress due to the water deficit is a tool of high scientific value for the specific case of rice, since this plant has the capacity to adapt to tolerate the presence of a sheet of water throughout its biological cycle and is highly susceptible to water deficit.

SIMULATION OF GROWTH AND MORPHOLOGICAL DEVELOPMENT OF MAIZE UNDER CONTRASTING WATER REGIMES

1989 ◽  
Vol 69 (2) ◽  
pp. 401-418 ◽  
Author(s):  
R. F. GRANT ◽  
J. R. FREDERICK ◽  
J. D. HESKETH ◽  
M. G. HUCK
Keyword(s):  
Leaf Area ◽  
Growth Models ◽  
Water Status ◽  
Leaf Sheath ◽  
Crop Growth ◽  
Control Treatment ◽  
Morphological Development ◽  
Shallow Water Table ◽  
Maize Crop ◽  
Node Number

The use of crop growth models for resource management decisions such as weed control will require the detailed simulation of plant structures and functions in order to determine crop response to resources. A crop growth model was constructed on the computing facility at the National Center for Supercomputing Applications which was intended to simulate the effect of changing water status on plant growth processes. The model was tested against field data collected during an experiment in which the morphology of a maize crop growing under an imposed water deficit over a shallow water table was compared to that of an irrigated control treatment. The effects of this deficit on soil and canopy water status, leaf tip appearance, and on the distribution of growth with node number were compared for the simulated and recorded data. The use of simple equations describing the partitioning of growth to successive nodes enabled reasonably accurate estimates to be made of the distribution of leaf, sheath and internode mass with node number during both deficit and irrigated treatments. Consequently, realistic estimates of the vertical distribution of leaf area could be made for use in subsequent studies of inter-specific competition for irradiance interception.Key words: Simulation modelling, water stress, leaf area, canopy, maize growth

RESPONSE OF DIFFERENT VARIETIES OF FABA BEAN TO PLANT SOURCE ORGANIC FERTILIZERS

2017 ◽  
Vol 48 (4) ◽  
Author(s):  
Dhary & Al-Baldawi
Keyword(s):  
Leaf Area ◽  
Seed Yield ◽  
Block Design ◽  
Winter Season ◽  
Chemical Fertilizer ◽  
Glycyrrhiza Glabra ◽  
Organic Fertilizers ◽  
Control Treatment ◽  
Heliotropium Europaeum ◽  
And Control

A  Field experiment was conducted during winter season at 2015 – 2016 at the experimental farm, department of Field Crop, College of Agriculture, University of Baghdad / Jadriyah to investigate effect of Organic Fertilizers preparation from weed plants on various broad bean varieties behavior and relationships with seed yield and its components. A randomized complete block design (RCBD) arranged according to split-plots used with three replicates including four organic fertilizers prepared from weeds Licorice (Glycyrrhiza glabra), Mallow (Malva rotundifolia), Purslane (Portulaca oleracea), European Heliotropic (Heliotropium europaeum), chemical fertilizer and control (without fertilizer) treatments, main plots included three varieties of Bean (Netherlands, Spanish and Locality ). The results showed that application of fertilizers significantly effect on studied characters, the treatment of Glycyrrhiza glabra gave higher rate of yield 3417 Kg ha-1, and There were no significant differences between Glycyrrhiza glabra and chemical fertilizer (NPK) at seed yield. Application of NPK showed highest No. of branches per plant, leaf area, thus reduction the flower portion percentage (4.02%) and increase pod numbers per plant and seed number per pod compared to control treatment. The results showed significant differences between varieties. The Spanish variety gave highest means of No. of branches per plant and leaf area per plant, thus reducing the flower portion and increase the number of pods per plant, number of seeds per pod and seed yield 3231 Kg ha-1. The Netherland variety gave higher weight of 100 seeds 47.94 g than the other varieties. Also, the most of characters were significantly influenced by interaction between varieties and fertilizers.

Influence of fertilization on the allometric relations for two pines in contrasting environments

1993 ◽  
Vol 23 (8) ◽  
pp. 1704-1711 ◽  
Author(s):  
Stith T. Gower ◽  
Brent E. Haynes ◽  
Karin S. Fassnacht ◽  
Steve W. Running ◽  
E. Raymond Hunt Jr.
Keyword(s):  
Leaf Area ◽  
Ponderosa Pine ◽  
Cross Sectional Area ◽  
Red Pine ◽  
Stem Diameter ◽  
Sectional Area ◽  
Cross Sectional ◽  
Breast Height ◽  
Allometric Relations ◽  
And Control

The objective of this study was to examine the effect of fertilization on the allometric relations for red pine (Pinusresinosa Ait.) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) growing in contrasting climates. After 2 years of treatment, fertilization did not significantly affect the allometric relations between stem or branch mass and stem diameter for either species. For a similar-diameter tree, current foliage mass and area and new twig mass were significantly greater for fertilized than for control red pine and ponderosa pine. The significant increase in new foliage mass and area occurred in the upper and middle canopy for red pine and middle and lower canopy for ponderosa pine. For a similar-diameter tree, projected (one-sided) leaf area and total foliage mass were significantly greater for fertilized than for control red pine. However, leaf area and total foliage mass did not differ between similar-diameter fertilized and control ponderosa pine because fertilization decreased leaf longevity. The ratios of leaf area/sapwood cross-sectional area measured at breast height (1.37 m) were 0.14 and 0.11 for control plus fertilized red pine and ponderosa pine, respectively, and were greater (but not significantly) for fertilized than for control trees, while the ratios of leaf area/sapwood cross-sectional area measured at the base of live crown were significantly greater for fertilized than for control red pine and ponderosa pine.

scholarly journals Assessing shaded-leaf effects on photochemical reflectance index (PRI) for water stress detection in winter wheat

2019 ◽  
Vol 16 (15) ◽  
pp. 2937-2947 ◽  
Author(s):  
Xin Yang ◽  
Shishi Liu ◽  
Yinuo Liu ◽  
Xifeng Ren ◽  
Hang Su
Keyword(s):  
Water Stress ◽  
Winter Wheat ◽  
Water Status ◽  
Control Treatment ◽  
Growth Stages ◽  
Linear Regression Models ◽  
Photochemical Reflectance Index ◽  
Crop Density ◽  
The Difference ◽  
The Impact

Abstract. The photochemical reflectance index (PRI) has emerged to be a pre-visual indicator of water stress. However, whether the varying shaded-leaf fractions, which may be caused by multiple view angles or the changing crop density in the field, affect the performance of PRI in detecting water stress of crops is still uncertain. This study evaluated the impact of the varying shaded-leaf fractions on estimating relative water content (RWC) across growth stages of winter wheat using seven formulations of PRI. Results demonstrated that for the control treatment the mean PRI of sunlit leaves was slightly higher than those of shaded leaves, but the difference between PRI of sunlit and shaded leaves increased as water resources became more limiting. Despite the difference between PRI of sunlit and shaded leaves, the significance of the linear relationship between RWC and most studied formulations of PRI did not show obvious variations with shadow fractions, except for the 100 % shaded-leaf condition. Among the studied formulations of PRI, PRI3 based on reflectance at 512 nm as the reference band provided the most accurate estimates of RWC with varying shaded-leaf fractions, except for the 100 % shaded-leaf condition. The slope and the intercept of linear regression models with PRI3 also showed minimized variations with shaded-leaf fractions. We then applied a uniform RWC prediction model to the data of varying shaded-leaf fractions and found that the accuracy of RWC predictions was not significantly affected in the mixture of sunlit and shaded leaves. However, RWC estimated with PRI of the 100 % shaded-leaf condition had the highest root mean square error (RMSE), implying that PRI of the pure shaded leaves may yield inaccurate estimates of plant water status.

scholarly journals Grazing winter wheat relieves plant water stress and transiently enhances photosynthesis

2010 ◽  
Vol 37 (8) ◽  
pp. 726 ◽  
Author(s):  
Matthew T. Harrison ◽  
Walter M. Kelman ◽  
Andrew D. Moore ◽  
John R. Evans
Keyword(s):  
Water Stress ◽  
Leaf Area ◽  
Water Status ◽  
Leaf Water ◽  
Plant Water ◽  
Rubisco Activity ◽  
Leaf Water Status ◽  
Area Index ◽  
Plant Water Stress ◽  
The Impact

To model the impact of grazing on the growth of wheat (Triticum aestivum L.), we measured photosynthesis in the field. Grazing may affect photosynthesis as a consequence of changes to leaf water status, nitrogen content per unit leaf area (Na) or photosynthetic enzyme activity. While light-saturated CO2 assimilation rates (Asat) of field-grown wheat were unchanged during grazing, Asat transiently increased by 33–68% compared with ungrazed leaves over a 2- to 4-week period after grazing ended. Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively. Grazing did not alter Na. Using a photosynthesis model, we demonstrated that the increase in Asat after grazing required an increase in Rubisco activity of up to 53%, whereas the increase in Ci could only increase Asat by up to 13%. Increased Rubisco activity was associated with a partial alleviation of leaf water stress. We observed a 68% increase in leaf water potential of grazed plants that could be attributed to reduced leaf area index and canopy evaporative demand, as well as to increased rainfall infiltration into soil. The grazing of rain-fed grain cereals may be tailored to relieve plant water stress and enhance leaf photosynthesis.

Response to water stress of Italian alder seedlings from diverse geographic origins

1989 ◽  
Vol 19 (8) ◽  
pp. 1071-1076 ◽  
Author(s):  
M. Borghetti ◽  
S. Cocco ◽  
M. Lambardi ◽  
S. Raddi
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Leaf Area ◽  
Water Status ◽  
Net Photosynthesis ◽  
Severe Drought ◽  
Xylem Water Potential ◽  
Drought Treatment ◽  
Internal Water ◽  
Response To Water

The morphological and physiological response to water stress was studied in 2-year-old potted Italian alder (Alnuscordata Loisel.) seedlings. Leaf area, transpiration, stomatal conductance, and xylem water potential were measured during May 1987 on seedlings from five geographic sources grown (i) with soil water content close to field capacity and (ii) with a severe drought. Significant differences in leaf area were found, at the end of the experiment, between drought-stressed and well-watered plants. As drought progressed, plants displayed a reduction of xylem water potentials and a decrease in stomatal conductance. However, transpiration did not stop completely, and seedlings were not able to maintain a favourable internal water status. Osmotic potentials for the undiluted cell sap, estimated from pressure–volume curves, were between −0.9 and −1.3 MPa. In June 1988, a similar experiment was carried out using seedlings from only one geographic source. A simultaneous decrease of transpiration, xylem potential, and net photosynthesis was observed in seedlings subjected to the drought treatment. During both experiments, a recovery of physiological parameters was observed, after rewatering. Some differences between provenances were detected. The provenance from Corsica showed the greatest sensitivity to water stress; a seed source from the province of Avellino (Campania, south Italy) was able to maintain a more favourable internal water status, as drought progressed.

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