scholarly journals RESPONSE OF ONION TO DIFFERENT LEVELS OF IRRIGATION WATER AND FERTILIZATION: (I) SOIL MOISTURE CONTENT, GROWTH PARAMETERS AND BULB YIELD

2013 ◽  
Vol 30 (3) ◽  
pp. 865-884
Author(s):  
Ahmed M. Hassan
Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1559
Author(s):  
Marija Đurić ◽  
Angelina Subotić ◽  
Ljiljana Prokić ◽  
Milana Trifunović-Momčilov ◽  
Aleksandar Cingel ◽  
...  

This study was carried out to examine the drought effect on development, physiological, biochemical and molecular parameters in Impatiens walleriana grown ex vitro. Experiment design included three treatments: Control plants—grown under optimal watering (35%–37% of soil moisture content), drought-stressed plants—non-irrigated to reach 15% and 5% of soil moisture content and recovery plants—rehydrated for four days to reach optimal soil moisture content. Drought reduced fresh weight, total leaf area, as well as dry weight of I. walleriana shoots. Drought up-regulated expression of abscisic acid (ABA) biosynthesis genes 9-cis-epoxycarotenoid dioxygenase 4 (NCED4) and abscisic aldehyde oxidase 2 (AAO2) and catabolic gene ABA 8′-hydroxylase 3 (ABA8ox3) which was followed by increased ABA content in the leaves. Decrement in water potential of shoots during the drought was not accompanied with increased amino acid proline content. We detected an increase in chlorophyll, carotenoid, total polyphenols and flavonols content under drought conditions, as well as malondialdehyde, hydrogen peroxide and DPPH (1,1′-diphenyl-2-picrylhydrazyl) activity. Increased antioxidant enzyme activities (superoxide dismutase, peroxidase and catalase) throughout drought were also determined. Recovery treatment was significant for neutralizing drought effect on growth parameters, shoot water potential, proline content and genes expression.


1984 ◽  
Vol 97 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Kiyokazu Suehiro ◽  
Kazuo Hozumi ◽  
Kichiro Shinozaki

2021 ◽  
Vol 12 ◽  
Author(s):  
Haowen Luo ◽  
Meiyang Duan ◽  
Leilei Kong ◽  
Longxin He ◽  
Yulin Chen ◽  
...  

2-acetyl-1-pyrroline (2-AP) is the key compound of rice aroma. However, the responses of 2-AP biosynthesis in fragrant rice under different soil moisture and the corresponding mechanism are little known. The present study evaluated the effects of different soil moisture on 2-AP biosynthesis through a pot experiment. Four soil moisture contents, that is, 50% (SM50), 40% (SM40), 30% (SM30), and 20% (SM20), were adopted, and SM50 treatment was taken as control. The pots were weighed and watered to maintain the corresponding soil moisture content. The results showed no significant difference in growth parameters (plant height, stem diameter, and plant dry weight) among all treatments. Compared with SM50, SM40, SM30, and SM20 treatments significantly (p<0.05) increased 2-AP content by 32.81, 23.18, and 53.12%, respectively. Between 20 to 90% higher proline content was observed in SM40, SM30, and SM20 treatments than in SM50. Enzymes including proline dehydrogenase, ornithine transaminase, and 1-pyrroline-5-carboxylate synthetase exhibited lower activities with soil moisture declined. Higher diamine oxidase activity was observed in SM40, SM30, and SM20 treatments compared with SM50, and real-time PCR analyses showed that transcript level of DAO1 was greatly increased under low soil moisture treatments, especially in SM20 treatment. Transcript levels of PRODH, DAO2, DAO4, DAO5, OAT, P5CS1, and P5CS2 decreased or maintained in SM40, SM30, and SM20 treatments compared with SM50. We deduced that low soil moisture content enhanced 2-AP biosynthesis mainly by upregulating the expression of DAO1 to promote the conversion from putrescine to 2-AP.


1954 ◽  
Vol 35 (2) ◽  
pp. 63-68 ◽  
Author(s):  
John R. Mather

A method of computing daily values of soil moisture from climatic data is described and comparisons with measured soil moisture values are given. Because the soil moisture values are obtained from climatic data only, past values of soil moisture content, unavailable otherwise, can be determined for any place for which climatic data are available. A long record of soil moisture is computed for one locality and estimates of the probabilities of occurrence of different levels of soil moisture are made. Such estimates are essential in any realistic long range planning.


2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.


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