Seasonal variation in standing crop, density and leaf growth rate of the seagrass, Heterozostera tasmanica, in western Port and Port Phillip Bay, Victoria, Australia

1983 ◽  
Vol 16 (2) ◽  
pp. 111-136 ◽  
Author(s):  
Douglas A. Bulthuis ◽  
Wm.J. Woelkerling
Keyword(s):  
Growth Rate ◽  
Seasonal Variation ◽  
Standing Crop ◽  
Leaf Growth ◽  
Crop Density

scholarly journals Morphogenesis and forage accumulation of Urochloa ruziziensis under nitrogen and potassium fertilization management

2019 ◽  
Vol 40 (4) ◽  
pp. 1605
Author(s):  
Karla Rodrigues de Lima ◽  
Carlos Augusto Brandão de Carvalho ◽  
Flavio Henrique Vidal Azevedo ◽  
Fabio Prudêncio de Campos ◽  
Aline Barros da Silva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Accumulation Rate ◽  
Leaf Growth ◽  
Stem Elongation ◽  
Block Design ◽  
Elongation Rate ◽  
Repeated Measurements ◽  
Positive Form ◽  
Potassium Fertilization ◽  
Appearance Rate

The objective of this study was to evaluate the effect of nitrogen and potassium fertilization on the morphogenetic and structural characteristics and production of Urochloa ruziziensis in two summer seasons (summer 1, 2010–2011and summer 2, 2011–2012) and the autumn and spring of 2011. A randomized complete block design with four treatments (0, 120, 240, and 360 kg ha-1 year-1 of N and K2O) and five replications was used, with repeated measurements in each season, in a split plot arrangement. The treatments were allocated to the plots and the seasons of the year to the subplots. The phyllochron (PHY),leaf appearance rate (LAR), leaf elongation rate (LER), stem elongation rate (SER), tiller population density (TPD), tiller appearance rate (TAR), tiller mortality rate (TMR), leaf growth rate (LGR), stem growth rate (SGR), senescence rate (SR), forage accumulation rate (FAR), and leaf accumulation rate (LAR) of Urochloa ruziziensis were evaluated. There was a positive quadratic effect for the PHY and ELR, with maximum values of 4.3 days leaf-1 and 0.43 cm tiller-1 day-1, respectively. While the SER increased linearly (0.0012 cm day-1 kg-1 of N and K2O) during summer 2. The TPD, TAR, and TMR increased linearly (averages of 1.53 tillers m-2, 0.04% and 0.02% per kg of N and K2O, respectively) with nitrogen and potassium fertilization during spring and both summer seasons. The LGR, SGR, and SR also increased linearly with N and K2O application rates during summer 2 (0.2809, 0.0082, and 0.0411 kg DM ha-1 day-1, per kg of N and K2O, respectively), while the FAR and LAR increased in a quadratic positive form (maximum values of 175 and 129 kg dry matter (DM) ha-1, corresponding to 294 and 237 kg ha-1 of N and K2O, respectively) during summer 2. Urochloa ruziziensis is a forage plant with a high DM production capacity during the summer and a high seasonal forage production.

Water Stressed Nodal Roots of Wheat: Effects on Leaf Growth

1997 ◽  
Vol 24 (1) ◽  
pp. 49 ◽  
Author(s):  
K. M. Volkmar
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Growth ◽  
Seminal Root ◽  
Nodal Roots ◽  
Nodal Root ◽  
Relative Water ◽  
Seminal Roots ◽  
Leaf Relative Water Content

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.

Effect of root zone aeration on the growth and bioactivity of cucumber plants cultured in perlite substrate

Biologia ◽  
2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Jong Lee ◽  
Beom Lee ◽  
Jong Kang ◽  
Jong Bae ◽  
Yang Ku ◽  
...  
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Bioactive Compounds ◽  
Root Zone ◽  
Antioxidant Activities ◽  
Leaf Growth ◽  
Co2 Concentration ◽  
Fruit Yield ◽  
Area Index ◽  
Antioxidant Power

AbstractThis study was aimed at investigating the growth and nutrient uptake of cucumber plants affected by forced aeration of supplying oxygen and stimulating gas exchange rate in root zone in a substrate. Five aeration levels during the growth (0, 0.5, 1.0, 1.5 and 2.0 L/min) were applied. Maximum leaf area and leaf fresh and dry weights were obtained at an aeration level of 0.5 L/min. Excessive aeration in root zone inhibited leaf area expansion, relative leaf growth rate and crop growth rate. An optimum leaf area index of 3.0 to 3.5 was estimated in range of 0 and 0.5 L/min. The highest fruit yield was measured of 1.13 kg/plant at 0.5 L/min, whereas at 2.0 L/min it was 0.62 kg/plant. Potassium concentration in petiole sap was lower at 63 days after transplanting than that at 32 days after transplanting. Ethylene concentrations increased with higher aeration values, however, CO2 concentration reduced with increased aeration. All bioactive compounds (polyphenols, flavonoids, flavanols, tannins and ascorbic acid) and the levels of antioxidant activities by ferric-reducing/antioxidant power and cupric reducing antioxidant capacity in ethanol extracts of cucumbers differed significantly in the investigated samples and were the highest at aeration level of 0.5 L/min in comparison with other samples (P <0.05). In conclusion, antioxidant status (bioactive compounds and antioxidant activities) improved with the appropriate aeration, which is effective for higher fruit yield and bioactivity. Excessive aeration inhibited root respiration, nutrients, bioactivity, and water uptake, and it resulted in the reduction of plant growth and fruit yield.

scholarly journals Development and Abortion of Flowers in Capsicum annuum Exposed to High Temperatures

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 476A-476
Author(s):  
Ami N. Erickson ◽  
Albert H. Markhart
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Capsicum Annuum ◽  
High Temperatures ◽  
Floral Development ◽  
Leaf Growth ◽  
Flower Initiation ◽  
Treatment Rate ◽  
Flower Bud ◽  
Stage Of Development

Reduction of floral number in Capsicum annuum has been observed during growth at high temperature. To determine whether decreased flower production or increased flower abscission is a direct response to high temperatures or a response to water stress induced by high temperatures, we compared flowers and fruit produced and flowers aborted to leaf growth rate, osmotic potential, stomatal conductance, and chlorophyll fluorescence of two cultivars. To determine the stage(s) of floral development that are most sensitive to high temperatures, flower buds were wax-embedded and examined at each stage of development during heat treatment. Rate of floral development also was examined. At first visible floral bud initiation, plants were transferred to each of three controlled environment growth chambers with set temperatures and vapor pressure deficits (VPD) of 25°C, 1.1 kPa; 33°C, 1.1 kPa; and 33°C, 2.1 kPa. Flower bud production and leaf growth rate were not significantly affected by high temperatures. Pepper fruit set, however, was inhibited at 33°C at either VPD. Preliminary water relations data suggested that water potentials were more negative under high temperature conditions. Differences in leaf fluorescence were statistically significant for temperature treatments, but not for VPD. Temperature is the primary factor in the decrease of fruit production in pepper. Decreased production is due to flower abortion and not to decreased flower initiation or plant growth.

scholarly journals Conformal growth of Arabidopsis leaves

2016 ◽  
Author(s):  
Graeme Mitchison
Keyword(s):  
Growth Rate ◽  
Leaf Growth ◽  
Good Precision ◽  
Conformal Map ◽  
Linear Gradient ◽  
Moebius Transformation ◽  
Position Data ◽  
Changes Over Time ◽  
Over Time

AbstractI show that Arabidopsis leaf growth can be described with good precision by a conformal map, where expansion is locally isotropic (the same in all directions) but the amount of expansion can vary with position. Data obtained by tracking leaf growth over time can be reproduced with almost 90% accuracy by such a map. The growth follows a Moebius transformation, which is a type of conformal map that would arise if there were an underlying linear gradient of growth rate. From the data one can derive the parameters that describe this linear gradient and show how it changes over time. Growth according to a conformal map has the property of maintaining the flatness of a leaf.

scholarly journals Growth analysis in relation to sowing dates in four varieties of wheat: a functional approach

1970 ◽  
Vol 2 (2) ◽  
pp. 17-25
Author(s):  
SA Haider
Keyword(s):  
Growth Rate ◽  
Leaf Growth ◽  
Weight Ratio ◽  
Sowing Date ◽  
Functional Approach ◽  
Crop Growth Rate ◽  
Stages Of Growth ◽  
Key Words Wheat ◽  
Sowing Dates ◽  
Net Assimilation

Effect of three different sowing dates on growth of four varieties of wheat was analyzed using functional techniques. Crop growth rate (CGR), relative leaf growth rate (RLGR) and specific leaf area (SLA) were higher in the early sown plants compared to late sown plants. Net assimilation rate (NAR) in all the varieties increased slowly at the early stages of growth while it increased sharply at the later stages with fluctuations in most cases. The declining tendency was found in SLA at the middle stage of growth except variety C 306. Higher values of CGR were found in the early sown Protiva, leaf weight ratio (LWR) in the late sown C 306 and early sown Opata, RLGR in the early sown Opata and C 306, SLA in the late sown Opata and Protiva and NAR in all the four varieties when they were sown late. Key words: Wheat; sowing date; growth; functional technique DOI: 10.3329/jles.v2i2.7492 J. Life Earth Sci., Vol. 2(2) 17-25, 2007  

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