Early Pinus caribaea var. hondurensis root development. 2. Influence of soil strength

The influence of penetration resistance (PR), an easily measured indicator of soil strength, on the growth of Pinus caribaea var. hondurensis radicles and seedlings was investigated. Negative exponential relationships between PR and both radicle and primary root elongation were observed. All root elongation ceased at PR levels of 3.25 MPa. Tip diameters of radicles and primary roots were positively correlated with PR values up to 2.4 MPa, whilst numbers of primary roots, total root lengths and lengths of longest roots were all negatively correlated with PR. Hypocotyl elongation was also reduced by increasing PR, although the reductions occurred at higher PRs than those which inhibited root development. In contrast, primary shoot development was unaffected by PR levels which were sufficient to stop root elongation, but was reduced in soil with a PR of 4.8 MPa. There were significant family x soil type and family x PR interactions for radicle, hypocotyl, primary root and primary shoot development. 1f these interactions are correlated with performance in the field, then they may serve as useful indicators of family suitability to both soil type and high strength soils.

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Brassinolide Increases Potato Root GrowthIn Vitroin a Dose-Dependent Way and Alleviates Salinity Stress

BioMed Research International ◽

10.1155/2016/8231873 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 11

Author(s):

Yueqing Hu ◽

Shitou Xia ◽

Yi Su ◽

Huiqun Wang ◽

Weigui Luo ◽

...

Keyword(s):

Salt Stress ◽

Stress Tolerance ◽

Root Development ◽

Root Elongation ◽

Primary Root ◽

Root Activity ◽

Dependent Manner ◽

Potato Root ◽

Dose Dependent

Brassinosteroids (BRs) are steroidal phytohormones that regulate various physiological processes, such as root development and stress tolerance. In the present study, we showed that brassinolide (BL) affects potato rootin vitrogrowth in a dose-dependent manner. Low BL concentrations (0.1 and 0.01 μg/L) promoted root elongation and lateral root development, whereas high BL concentrations (1–100 μg/L) inhibited root elongation. There was a significant (P<0.05) positive correlation between root activity and BL concentrations within a range from 0.01 to 100 μg/L, with the peak activity of 8.238 mg TTC·g−1FW·h−1at a BL concentration of 100 μg/L. Furthermore, plants treated with 50 μg/L BL showed enhanced salt stress tolerance throughin vitrogrowth. Under this scenario, BL treatment enhanced the proline content and antioxidant enzymes’ (superoxide dismutase, peroxidase, and catalase) activity and reduced malondialdehyde content in potato shoots. Application of BL maintain K+and Na+homeostasis by improving tissue K+/Na+ratio. Therefore, we suggested that the effects of BL on root development from stem fragments explants as well as on primary root development are dose-dependent and that BL application alleviates salt stress on potato by improving root activity, root/shoot ratio, and antioxidative capacity in shoots and maintaining K+/Na+homeostasis in potato shoots and roots.

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Site preparation for Pinus establishment in south-eastern Queensland. 2. Effect of cultivation and cultivation width on growth

Australian Journal of Experimental Agriculture ◽

10.1071/ea9951159 ◽

1995 ◽

Vol 35 (8) ◽

pp. 1159 ◽

Cited By ~ 2

Author(s):

A Costantini ◽

M Podberscek ◽

MR Nester

Keyword(s):

Soil Type ◽

Growth Response ◽

High Strength ◽

Penetration Resistance ◽

Site Preparation ◽

Plantation Establishment ◽

Growth Responses ◽

Pinus Caribaea ◽

South Eastern ◽

Soil Penetration Resistance

The standard site preparation practice used for Pinus plantation establishment on well-drained soils in south-eastern Queensland is blade (subsurface, wing rip) cultivation to a width of 2.0 m and a depth of 0.2 m. This operation requires high drawbar power and is difficult to achieve in high strength soils, or in soils where roots and stumps hinder progress of the blade through the soil. The aim of the study reported in this paper was to better define cultivation growth relationships for Pinus caribaea var. hondurensis plantations in order to determine if site preparation objectives could be achieved with a reduced cultivation effort. A highly significant 'soil type x cultivation' interaction was observed. In contrast to the growth responses observed on hardsetting soils, cultivation did not improve growth on non-hardsetting soils. There is an opportunity therefore to reduce reforestation site preparation costs by only cultivating soils that show a growth response. The cultivation response on hardsetting soils has increased throughout the study period, and is attributed to a reduction in soil penetration resistance. The response however shows diminishing gains with increasing cultivation widths. Blade cultivation widths of 1.2 m were found to capture 97% of the gains that could be expected from widths of 2.0 m. A significant 'family x soil penetration resistance' interaction was observed. An opportunity to increase plantation productivity by targeting better performing families to hardsetting soils is suggested.

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Primary Root Elongation Rate and Abscisic Acid Levels of Maize in Response to Water Stress

Crop Science ◽

10.2135/cropsci2009.12.0708 ◽

2011 ◽

Vol 51 (1) ◽

pp. 157-172 ◽

Cited By ~ 16

Author(s):

Kristen A. Leach ◽

Lindsey G. Hejlek ◽

Leonard B. Hearne ◽

Henry T. Nguyen ◽

Robert E. Sharp ◽

...

Keyword(s):

Abscisic Acid ◽

Water Stress ◽

Root Elongation ◽

Primary Root ◽

Elongation Rate ◽

Root Elongation Rate ◽

Response To Water

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Two Expansin Genes, AtEXPA4 and AtEXPB5, Are Redundantly Required for Pollen Tube Growth and AtEXPA4 Is Involved in Primary Root Elongation in Arabidopsis thaliana

Genes ◽

10.3390/genes12020249 ◽

2021 ◽

Vol 12 (2) ◽

pp. 249

Author(s):

Weimiao Liu ◽

Liai Xu ◽

Hui Lin ◽

Jiashu Cao

Keyword(s):

Arabidopsis Thaliana ◽

Pollen Tube ◽

Pollen Tube Growth ◽

Cell Walls ◽

Root Elongation ◽

Expression Patterns ◽

Primary Root ◽

Pollen Grains ◽

Tube Growth ◽

Cell Wall Binding

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.

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The bacterial volatile N,N-dimethyl-hexadecylamine promotes Arabidopsis primary root elongation through cytokinin signaling and the AHK2 receptor

Plant Signaling & Behavior ◽

10.1080/15592324.2021.1879542 ◽

2021 ◽

Vol 16 (4) ◽

pp. 1879542

Author(s):

Ernesto Vázquez-Chimalhua ◽

Salvador Barrera-Ortiz ◽

Eduardo Valencia-Cantero ◽

José López-Bucio ◽

León Francisco Ruiz-Herrera

Keyword(s):

Root Elongation ◽

Primary Root ◽

Cytokinin Signaling

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Involvement of calmodulin in regulation of primary root elongation by N-3-oxo-hexanoyl homoserine lactone in Arabidopsis thaliana

Frontiers in Plant Science ◽

10.3389/fpls.2014.00807 ◽

2015 ◽

Vol 5 ◽

Cited By ~ 17

Author(s):

Qian Zhao ◽

Chao Zhang ◽

Zhenhua Jia ◽

Yali Huang ◽

Haili Li ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Root Elongation ◽

Primary Root ◽

Homoserine Lactone

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Identification and characterization of novel QTL conferring internal detoxification of aluminum in soybean

Journal of Experimental Botany ◽

10.1093/jxb/erab168 ◽

2021 ◽

Author(s):

Yang Li ◽

Heng Ye ◽

Li Song ◽

Tri D Vuong ◽

Qijian Song ◽

...

Keyword(s):

Root Length ◽

Root Elongation ◽

Primary Root ◽

Pedigree Analysis ◽

Length Ratio ◽

Root Tip ◽

Root Initiation ◽

Al Tolerance ◽

Al Stress ◽

Root Length Ratio

Abstract Aluminum (Al) toxicity inhibits soybean root growth, leading to insufficient water and nutrient uptake. In this research, two soybean lines (Magellan and PI 567731) were identified differing in Al tolerance as determined by primary root length ratio (PRL_Ratio), total root length ratio (TRL_Ratio), and root tip number ratio (RTN_Ratio) under Al stress compared to unstressed controlled conditions. Serious root necrosis was observed in PI 567731, but not in Magellan under Al stress. An F8 recombinant inbred line population derived from a cross between Magellan and PI 567731 was used to map the quantitative trait loci (QTL) for Al-tolerance. Three QTL on chromosomes 3, 13, and 20, with tolerant-alleles from Magellan, were identified. qAl_Gm13 and qAl_Gm20, explained large phenotypic variations (13-27%) and played roles in maintaining root elongation. qAl_Gm03 was involved in maintaining root initiation under Al stress. These results suggested the importance of using the parameters of root elongation and root initiation in Al tolerance studies. In addition, qAl_Gm13 and qAl_Gm20 were confirmed in near-isogenic backgrounds and were identified to epistatically regulate Al tolerance in internal detoxification instead of Al 3+ exclusion. The candidate genes for qAl_Gm13 and qAl_Gm20 were suggested by analyzing a previous RNA-seq study. Phylogenetic and pedigree analysis identified the tolerant alleles of both loci derived from the US ancestor line, A.K.[FC30761], originally from China. Our results provide novel genetic resources for breeding Al-tolerant soybeans and suggest that the internal detoxification contributes to soybean tolerance to excessive soil Al.

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