Effect of induced warming on seedling emergence of Tamaulipan thornscrub at Northeastern Mexico

Larval feeding by Phyllophaga crinita (Burmeister) and Anomala spp. (mixed populations of A. flavipennis Burmeister and A. foraminosa Bates) was studied under simulated field conditions in northern Tamaulipas, Mexico. Each month from July 1994 to February 1995, 50 field-collected larvae of P. crinita and Anomala spp. were placed individually in plastic pots with soil and corn seeds, and damage was evaluated 10 d after seedling emergence. Secondinstar P. crinita caused 41% root loss in July, whereas third instars caused most damage (66–88% root loss) during July–September. Feeding by P. crinita decreased gradually from October to December, and ceased in January–February. In contrast, feeding by Anomala spp. peaked in July and again in November (73 and 53% root loss, respectively), a result of the bivoltine life cycle of these species in this region. The relationship of these findings to similar studies is discussed.

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Ten Native Tree Species for potential use in Soil Bioengineering in northeastern Mexico

Botanical Sciences ◽

10.17129/botsci.2131 ◽

2019 ◽

Vol 97 (3) ◽

pp. 291

Author(s):

Rebeca Zavala González ◽

Israel Cantú-Silva ◽

Laura Sánchez-Castillo ◽

Humberto González-Rodríguez ◽

Tetsuya Kubota ◽

...

Keyword(s):

Tensile Strength ◽

Modulus Of Elasticity ◽

Oak Forest ◽

Nuevo Leon ◽

Acacia Berlandieri ◽

Soil Bioengineering ◽

Group I ◽

Nuevo León ◽

Northeastern Mexico ◽

Tamaulipan Thornscrub

Background: Due to causes such as small-scale earthquakes or the increasing amount of heavy rainfall extreme events, many slopes are potentially unstable. Soil bioengineering is an effective tool for treatment of a variety of unstable and/ or eroding sites.Question and hypothesis: Maximum force to breakage of the roots is influenced by diameter.Tensile strength and modulus of elasticity of roots is different between species of the two different ecosystems: Tamaulipan thornscrub and Pine-oak forest.Studied Species: Site 1: Acacia berlandieri, Cordia boissieri, Acacia rigidula, Havardia pallens, and Acacia farnesiana; Site 2: Quercus rysophylla, Pinus pseudostrobus, Quercus canbyi, Quercus polymorpha, and Arbutus xalapensis.Study area and dates: Tamaulipan thornscrub in Northeastern Mexico (Linares, Nuevo León), from May to July 2016; and Pine-Oak forest in Sierra Madre Oriental, Iturbide, Nuevo Leon, from September to October 2016.Methods: The species considered were selected based on their native characteristics (natural distribution, abundance in the area and widespread existence on slopes). The tests were conducted with the Universal Testing Machine Shimadzu type SLFL-100KN.Results: The relationships between tensile strength (Ts) and diameters of the studied species, and root diameters and modulus of elasticity (Eroot) were negative.The minimum and maximum values of tensile strength varied from 1.86 N / mm2 in C. boissieri to 44.65 N/mm2 in A. rigidula.Conclusions: Acacia berlandieri showed the highest tensile strength among all species of the two ecosystems, in the diametric group I (0.1 to 2.9 mm).

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Genetic variation for rate of establishment in caucasian clover

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1998.60.2282 ◽

1998 ◽

pp. 213-217

Author(s):

K.H. Widdup ◽

T.L. Knight ◽

C.J. Waters

Keyword(s):

Genetic Variation ◽

Root Growth ◽

Seedling Growth ◽

White Clover ◽

Seedling Emergence ◽

Red Clover ◽

Dry Weight ◽

Cool Season ◽

Trifolium Ambiguum ◽

Root Dry Weight

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum

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