ISSN e: 2007-4018 / ISSN print: 2007-4018

English | Español

     

 
 
 
 
 
 
 
 

Vol. XXIII, issue 1 January - April 2017

ISSN: ppub: 2007-3828 epub: 2007-4018

Scientific note

Survival of plants of Pinus leiophylla Schiede ex Schltdl. & Cham., by adding water reservoirs at transplanting in a greenhouse

http://dx.doi.org/10.5154/r.rchscfa.2015.10.046

Palacios-Romero, Abraham 1 ; Rodríguez-Laguna, Rodrigo 2 * ; Razo-Zárate, Ramón 2 ; Meza-Rangel, Joel 2 ; Prieto-García, Francisco 1 ; Hernández-Flores, M. de la Luz 1

  • 1Universidad Autónoma del Estado de Hidalgo, Ciudad del Conocimiento. Carretera Pachuca-Tulancingo km 4.5. C. P. 42184. Mineral de la Reforma, Hidalgo. México.
  • 2Universidad Autónoma del Estado de Hidalgo, Instituto de Ciencias Agropecuarias. Av. Universidad km 1, Ex-hacienda de Aquetzalpa. A. P. 32 C. P. 43600. Tulancingo, Hidalgo. México.

Corresponding author. Email: rodris71@yahoo.com

Received: October 15, 2015; Accepted: October 04, 2016

This is an open-access article distributed under the terms of the Creative Commons Attribution License view the permissions of this license

Abstract

In Mexico, several reforestation programs have been launched; they generally fail to achieve good survival rates, mainly due to drought. To mitigate this, technologies that help plants survive in the early years should be generated. In light of this, the effect of adding water reservoirs at transplanting on survival, height, diameter and biomass of Pinus leiophylla plants, grown under simulated drought conditions in a greenhouse, was evaluated. Plants were arranged in a completely randomized design and four treatments were used: control, a 231-cc phenolic foam block, a 308-cc phenolic foam block and three grams of hydrogel, all hydrated with tap water. A survival analysis was performed, yielding significant difference between control and the other treatments (P = 0.000008). No statistically significant differences were found in height. Statistically significant differences were found in diameter among treatments at 8 (P = 0.013) and 12 weeks (P = 0.002). Statistically significant differences were detected in biomass among treatments (P = 0.0001). Adding hydrated open-cell phenolic foam at transplanting significantly increased survival time and diameter of P. leiophylla under drought conditions.

Keywords:phenolic foam; hydrogel; drought resistance; reforestation.

Introduction

Mexico is estimated to have lost more than 44 million hectares of forests over the past 60 years (Velázquez, Durán, Mas, Bray, & Bocco, 2005). Faced with this situation, several reforestation programs have been put in place, but they have generally failed to achieve the desired results because the plants used die from various causes such as: zero site preparation, grazing, competition with native vegetation, diseases and fires; however, the factors with the greatest impact are drought and inappropriate planting dates (Comisión Nacional Forestal [CONAFOR], Colegio de Postgraduados, & Secretaría de Medio Ambiente y Recursos Naturales [SEMARNAT], 2008).

Climate change has altered rainfall patterns, prolonging droughts, causing plants to be exposed to increased water stress and resulting in low survival in the field (Hanjra & Qureshi, 2010). Some technologies that help provide resistance to water stress in different species of commercial interest have been developed (Barón, Barrera, Boada, & Rodríguez, 2007). One of the technologies that has drawn the most attention is the use of hydrogel, a polymer capable of absorbing up to 400 mL of water per gram dry weight (Ahmed, 2013). However, it has been shown that soil texture can affect the performance of the hydrogel (Agaba et al., 2010), and water salinity can decrease its effectiveness (Akhter et al., 2004). Moreover, other authors state that applying the polymer does not provide benefits to plantations (Farrell, Ang, & Rayner, 2013).

In this regard, open-cell phenolic foam has been proposed as an alternative, being a thermosetting synthetic resin able to save more than 40 times its own weight in water without suffering deformation (Gardziella, Pilato, & Knop, 2000). Due to the foam’s physical structure, plant roots can pass through it and make use of the trapped water. This type of foam is used in hydroponic greenhouses and its effectiveness as a substrate is widely documented (Bezerra et al., 2010; Chugh, Guha, & Rao, 2009; da Silva, Kager, de Moraes, & Gonçalves, 2012).

Pinus leiophylla Schiede ex Schltdl. & Cham. is found in transition zones between natural Pinus and Quercus forests and agricultural areas, thus fulfilling the important role of forest protection and buffering. The species is valued for its use in the production of poles, furniture and wood pulp, as well as being a source of firewood and charcoal for rural communities and industries (Musálem & Martínez, 2003).

In light of the above, the aim of this study was to evaluate the effect of adding water reservoirs at transplanting on the survival, growth in height and diameter, and biomass of P. leiophylla plants grown under simulated drought conditions in a greenhouse.

Materials and methods

Experimental design

The trial was established in the Institute of Agricultural Sciences greenhouse at the Universidad Autónoma del Estado de Hidalgo, located at coordinates 20° 3’ 36.44” N and 98° 22’ 53.26” W. The one-year-old P. leiophylla plants were produced in a 77-cavity Styrofoam tray (170 cc per cavity). The substrate used was peat moss, perlite and vermiculite at a ratio of 3:1:1, with 6 g of Osmocote slow-release (eight months) fertilizer added per liter of mixture. Similar plants in height (25 to 30 cm) and diameter at the base (3.5 mm), disease-free, with . of the stem lignified and with fully developed fascicles and needles were selected. The treatments applied at transplanting are described in Table 1.

Table 1. Water reservoir treatments applied at transplanting of Pinus leiophylla in a greenhouse.

Treatment Description Placement
T1 Control. No phenolic foam blocks The plant was placed in a traditional way
T2 Hydrated phenolic foam block of 3.3 x 7 x 10 cm and 231 cc dry volume The block was placed on one side of the plant root ball, at a depth of 7 cm below the surface
T3 Hydrated phenolic foam block of 4.4 x 7 x 10 cm and 308 cc dry volume The block was placed on one side of the plant root ball, at a depth of 7 cm below the surface
T4 3 g of hydrated hydrogel The hydrogel was dispersed around the root ball, at a depth of 5-7 cm

Individual plants were transplanted into 40 x 40 x 40 cm plastic bags containing 30.6 L of agricultural soil (23 % initial moisture, 56.5 % total porosity, 10.2 % available water retention capacity and 89.7 % aeration porosity). Plants were placed in the center of the bags and treatments were applied around the root ball. Hydrated phenolic foam was deposited so as to have the largest possible contact surface with the root ball.

Subsequently, the filling of the pots was concluded and the soil was compacted slightly, removing lumps and large stones. The pots were placed in a plastic-covered 10 x 30 m greenhouse with an internal temperature ranging from 10 °C in the coldest time to 38 °C in the hottest time in November 2013. The pots were arranged in accordance with a completely randomized experimental design. Each treatment was formed by three replicates of 20 plants, resulting in a total of 60 individuals per treatment and 240 plants in the experiment. No water was added during the evaluation period, in order to assess the moisture contribution from the phenolic foams to the plant and evaluate survival and other variables under study.

Variables and analyses

The variables studied were survival, growth in height and diameter and increase in shoot and root biomass of the plant. Survival was evaluated visually each week for three months. The individual plant was considered dead when it lost turgor in the apical bud, the characteristic color of the species changed and it showed signs of wilting in the leaves, according to the methodology proposed by Barchuk and Díaz (2000). The increase in height was measured with a measuring tape (Trooper, Mexico) and that of diameter with a digital Vernier caliper (0.001 mm accuracy, Trooper, Mexico). Biomass was assessed using the methodology proposed by Schlegel, Gayoso, and Guerra (2000), which is to obtain, separately, the dry weight of the shoot and root of the plants that were dying in the course of the experiment; subsequently, the values were summed to obtain the total biomass.

Survival was analyzed using the Kaplan-Meier estimator (Sigala, González, & Jiménez, 2015), while height and diameter data were subjected to an analysis of covariance, using the individual value of initial height as a covariate (Palacios et al., 2015). The shoot, root and total biomass data were subjected to traditional analysis of variance. Variables that showed statistically significant differences (P ≤ 0.05) were subjected to Tukey’s range test

Results and discussion

Survival of P. leiophylla

Survival analysis, using the Kaplan-Meier estimator, showed a highly significant difference between control and the other treatments (P = 0.000008) (Figure 1). These results are similar to those reported by Agaba et al. (2010) and Orikiriza et al. (2013), who added hydrogel as a water reservoir in other tree species and concluded that the survival time increased. Table 2 shows a comparison between these studies.

Figure 1. Survival of Pinus leiophylla plants with different water reservoir treatments.

Table 2. Survival of different tree species by applying water reservoirs at transplanting.

Authors Species studied Days of survival
Control Hydrogel Phenolic foam
Agaba et al. (2010) Eucalyptus grandis W. Mill ex Maiden 24 40 -
Grevillea robusta A. Cunn. ex R. Br. 27 74 -
Maesopsis eminii Engl. 21 91 -
Melia volkensii Gürke 50 90 -
Pinus caribaea Morelet 32 59 -
Terminalia superba Engl. & Diels 21 76 -
Azadirachta indica A. Juss. 23 65 -
Araucaria cunninghamii Aiton ex D. Don 84 145 -
E. citriodora Hook. 42 50 -
Orikiriza et al. (2013) P. sylvestris L. 34 51 -
Picea abies (L.) H. Karst. 32 40 -
Fagus sylvatica L. 30 33 -
Present study Pinus leiophylla Schiede ex Schltdl. & Cham. 35 56 56

Figure 2 shows the survival rate of P. leiophylla under various treatments over a 12-week period. The figure shows that all the plants (100 %) of the four treatments survived during the first three weeks, so that errors during transplanting can be discarded. From the fourth week, plant survival decreased by 23 % in the control treatment and by 8 % in the phenolic foam treatments, while the treatment with hydrogel maintained 100 % of the plants until the fifth week. In this week, plant survival in the control treatment was 50 %, while the other groups recorded a rapid decline in the survival curve after the sixth week.

Figure 2. Survival of Pinus leiophylla plants with different water reservoir treatments.

At two months after the start of the experiment, the control was statistically different (P = 0.000008) from the other treatments by having only 8 % survival, while the hydrogel had 45 % and the 231-cc and 308-cc phenolic foam treatments had 52 and 62 %, respectively (Table 3).

Table 3. Weekly survival of Pinus leiophylla under different water reservoir treatments.

Treatment Weekly survival (%)
1 2 3 4 5 6 7 8 9 10 11 12
Control 100.0 a 100.0 a 100.0 a 76.7 a 51.7 b 43.3 b 19.7 b 8.3 b 3.3 a 3.3 a 3.3 a 1.7 a
Phenolic foam (231 cc) 100.0 a 100.0 a 100.0 a 92.0 a 88.0 a 88.0 a 75.0 a 52.0 a 32.0 a 15.0 a 10.0 a 5.0 a
Phenolic foam (308 cc) 100.0 a 100.0 a 100.0 a 92.0 a 90.0 a 87.0 a 78.0 a 62.0 a 40.0 a 20.0 a 17.0 a 13.0 a
Hydrated hydrogel (3 g) 100.0 a 100.0 a 100.0 a 100.0 a 100.0 a 91.7 a 45.0 a 45.0 a 20.0 a 13.3 a 11.6 a 8.3 a
*Values in the same column followed by a different letter indicate statistically significant differences according to the Kaplan-Meier estimator (P = 0.000008).

Survival time was extended 30 days by using a 308-c hydrated phenolic foam block. In an open field planting, there is a possibility of rain in that period, so that the plant recovers turgidity and the phenolic foam block is hydrated again. Al-Humaid and Moftah (2007) also reported that adding hydrogel increased survival to two months in Conocarpus erectus L individuals. In the present study, the 308-c phenolic foam kept 62 % of the P. leiophylla plants alive until 60 days after transplantation, while the hydrogel maintained 45 %; therefore, phenolic foam is another option to mitigate the effects of prolonged drought in the first months after transplantation.

Survival times are similar to those reported by Agaba et al. (2010) and Orikiriza et al. (2013) in other tree species (Table 2). It should be noted that they watered plants to field capacity before subjecting them to drought conditions and they applied irrigation to ensure establishment. Another study by da Silva et al. (2012) of the phenolic foam block is increased, survival in hybrid seedlings of Eucalyptus urophylla S.T. Blake and E. resinifera Sm. also increases. This is consistent with what was found in this study, since the 308-cc phenolic foam treatment showed 10 % more survival more than the 231-cc one.

Increase in height, diameter and biomass of Pinus leiophylla

The analysis of covariance showed no significant differences among treatments with respect to the increase in height at eight (P = 0.250) and 12 weeks (P = 0.135) (Table 4). Chirino, Vilagrosa, and Vallejo (2011) and Maldonado-Benitez, Aldrete, López-Upton, Vaquera- Huerta, and Cetina-Alcalá (2011) reported similar results and attributed them to drought conditions. Evaluation was made at week eight, because most of the plants of the different treatments maintained around 50 % survival, and at week 12, because almost all of the plants had died.

Table 4. Analysis of covariance for the variables height and diameter with water reservoir treatments in Pinus leiophylla.

Variable Week after transplanting Mean squares Pr > F
Treatment (3)* Error (235)*
Height 8 7.77 5.63 0.250
Height 12 10.44 5.58 0.135
Diameter 8 1.68 0.45 0.013
Diameter 12 2.33 0.46 0.002
*Degrees of freedom for each source of variation are shown in parentheses.

Regarding diameter, the analysis of covariance showed significant differences among treatments at eight (P = 0.013) and 12 weeks (P = 0.002). Table 5 shows the diameter growth of P. leiophylla plants under the four evaluated treatments. The control treatment had the smallest diameter (3.9 mm), while the increase of this variable in the phenolic foam and hydrogel treatments was similar. These results agree with those reported by De la O-Quezada, Ojeda-Barrios, Hernández-Rodríguez, Sánchez-Chávez, and Martínez-Tellez (2011), who indicate that, under water stress conditions, walnut seedlings are mainly affected in increase of diameter.

Table 5. Variation in diameter of Pinus leiophylla in different weeks of evaluation.

Treatment Average diameter in week 8 (mm) Average diameter in week 12 (mm)
Control 3.92 b 3.96 b
Phenolic foam (231 cc) 4.21 a 4.31 a
Phenolic foam (308 cc) 4.04 a 4.20 a
Hydrated hydrogel (3 g) 4.29 a 4.44 a
Values in the same column followed by a different letter indicate statistically significant differences according to the Tukey test (P ≤ 0.05).

Table 6 shows the analysis of variance of the shoot, root and total biomass with statistically significant differences (P ≤ 0.05) among the treatments. On the other hand, Figure 3 shows a graphical comparison of the biomass of P. leiophylla under the different treatments. The control treatment had the highest root biomass (0.99 g). In total biomass, the difference between the extreme values was 0.78 g, corresponding to the control and hydrogel treatments. In plants with phenolic foam, part of the roots was lost when removing the root system, because they went through the foam and it was impossible to separate them from it, an error that was not considered in the weighing. It is also important to mention that, according to Cornejo and Emmingham (2003), the results can be attributed to the fact that the evaluations were conducted during the cold season and in a short period (12 weeks), as the increase in biomass during the cold season under greenhouse conditions is not affected by water stress.

Table 6. Analysis of variance for the variables root, shoot and total biomass of Pinus leiophylla with water reservoir treatments.

Variable Mean squares Pr > F
Treatment (3)* Error (236)*
Root biomass 0.857 0.100 0.0001
Shoot biomass 3.954 0.625 0.0004
Total biomass 8.035 1.016 0.0001
*Degrees of freedom for each source of variation are shown in parentheses.

Figure 3. Biomass of P. leiophylla under different water reservoir treatments. Bars with the same pattern and a different letter indicate statistically significant differences according to the Tukey test (P ≤ 0.05).

Conclusions

Adding hydrated open-cell phenolic foam, at the time of transplanting P. leiophylla plants, significantly increased survival time under simulated drought conditions in a greenhouse to 63 days, compared to 35 days for the control and 49 days for the hydrated hydrogel treatment. A significant increase in diameter of up to 0.35 mm relative to the control was also observed; differences in the variable height were negligible. This type of study provides guidelines for further research and possible application of a new water reservoir system under conditions different from those of a greenhouse to help mitigate the effects of drought, increase survival and improve the establishment of pine plants.

References

Agaba, H., Baguma, O. L. J., Osoto, E. J. F., Obua, J., Kabasa, J. D., & Hüttermann, A. (2010). Effects of hydrogel amendment to different soils on plant available water and survival of trees under drought conditions. CLEAN - Soil, Air, Water, 38(4), 328-335. doi: 10.1002/clen.20090024510.1002/clen.200900245

Ahmed, E. M. (2013). Hydrogel: Preparation, characterization, and applications. Journal of Advanced Research, 6(2), 105- 121. doi: 10.1016/j.jare.2013.07.006

Akhter, J., Mahmood, K., Malik, K. A., Mardan, A., Ahmad, M., & Iqbal, M. M. (2004). Effects of hydrogel amendment on water storage of sandy loam and loam soils and seedling growth of barley, wheat and chickpea. Plant Soil Environment, 50(10), 463-469. Retrieved from http://www.agriculturejournals.cz/publicFiles/52788.pdf

Al-Humaid, A. I., & Moftah, A. E. (2007). Effects of hydrophilic polymer on the survival of buttonwood seedlings grown under drought stress. Journal of Plant Nutrition, 30(1), 53-66. doi: 10.1080/01904160601054973

Barchuk, A. H., & Díaz, M. P. (2000). Vigor de crecimiento y supervivencia de plantaciones de Aspidosperma quebracho-blanco y de Prosopis chilensis en el Chaco árido. Quebracho, 8, 17-29. Retrieved from http://fcf.unse.edu.ar/archivos/quebracho/q8_02-Barchuk.pdf

Barón, C. A., Barrera, R. I. X., Boada, E. L. F., & Rodríguez, N. G. (2007). Evaluación de hidrogeles para aplicaciones agroforestales. Ingeniería e Investigación, 27(3), 35-44. Retrieved from http://www.redalyc.org/articulo.oa?id=64327305

Bezerra, N. E., Santos, R., Pessoa, P., Andrade, P., Oliveira, S., & Mendonça, I. (2010). Tratamento de espuma fenólica para produção de mudas de alface. Revista Brasileira de Ciências Agrárias, 5(3), 418-422. Retrieved from http://www.redalyc.org/articulo.oa?id=119016971022

Chirino, E., Vilagrosa, A., & Vallejo, V. R. (2011). Using hydrogel and clay to improve the water status of seedlings for dryland restoration. Plant and Soil, 344(1- 2), 99-110. doi: 10.1007/s11104-011-0730-1

Chugh, S., Guha, S., & Rao, I. U. (2009). Micropropagation of orchids: A review on the potential of different explants. Scientia Horticulturae, 122(4), 507-520. doi: 10.1016/j.scienta.2009.07.016

Comisión Nacional Forestal (CONAFOR), Colegio de Postgraduados (COLPOS), & Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT). (2008). Reforestación. Evaluación externa ejercicio fiscal 2007. Retrieved from http://www.era-mx.org/biblio/Evaluacion_Colpos_Reforestacion_2007.pdf

Cornejo, O. D. H., & Emmingham, W. (2003). Effects of water stress on seedling growth, water potential and stomatal conductance of four Pinus species. Crop Research & Research on crops, 25(1), 159-190. Retrieved from http://cropresearch.org/volume-25-number-1-january-2003/

da Silva, M. P. H., Kager, D., de Moraes, G. J. L., & Gonçalves, A. N. (2012). Produção de mudas clonais de eucalipto em espuma fenólica: crescimento inicial e mortalidade. CERNE, 18(4), 639-649. Retrieved from http://www.redalyc.org/articulo.oa?id=74424807014

De la O-Quezada, G. A., Ojeda-Barrios, D. L., Hernández- Rodríguez, O. A., Sánchez-Chávez, E., & Martínez- Tellez, J. (2011). Biomasa, prolina y parámetros nitrogenados en plántulas de nogal bajo estrés hídrico y fertilización nitrogenada. Revista Chapingo Serie Horticultura, 17(1), 13-18. Retrieved from http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1027-152X2011000400003

Farrell, C., Ang, X. Q., & Rayner, J. P. (2013). Water-retention additives increase plant available water in green roof substrates. Ecological Engineering, 52, 112-118. doi: 10.1016/j.ecoleng.2012.12.098

Gardziella, A., Pilato, L. A., & Knop, A. (2000). Phenolic resins: Chemistry, applications, standardization, safety and ecology. New York, USA: Springer.

Hanjra, M. A., & Qureshi, M. E. (2010). Global water crisis and future food security in an era of climate change. Food Policy, 35(5), 365-377. doi: 10.1016/j.foodpol.2010.05.006

Maldonado-Benitez, K., Aldrete, A., López-Upton, J., Vaquera- Huerta, H., & Cetina-Alcalá, V. M. (2011). Producción de Pinus greggii Engelm. en mezclas de sustrato con hidrogel y riego en vivero. Agrociencia, 45(3), 389-398. Retrieved from http://www.scielo.org.mx/pdf/agro/v45n3/v45n3a11.pdf

Musálem, M. Á., & Martínez, G. S. (2003). Monografía de Pinus leiophylla. Chapingo, México: Instituto de Investigaciones Forestales, Agrícolas y Pecuarias. Retrieved from http://biblioteca.inifap.gob.mx:8080/jspui/handle/123456789/1817

Orikiriza, L. J. B., Agaba, H., Eilu, G., Kabasa, J. D., Worbes, M., & Hüttermann, A. (2013). Effects of hydrogels on tree seedling performance in temperate soils before and after water stress. Journal of Environmental Protection, 04(07), 713-721. doi: 10.4236/jep.2013.47082

Palacios, R. A., Rodríguez, L. R., Prieto, G. F., Meza, R. J., Razo, Z. R., & Hernández, F. M. L. (2015). Supervivencia de Pinus leiophylla Schiede ex Schltdl. et Cham. en campo mediante la aplicación de espuma fenólica hidratada. Revista Mexicana de Ciencias Forestales, 6(32), 83-92. Retrieved from http://cienciasforestales.inifap.gob.mx/editorial/index.php/Forestales/article/view/4127/3477

Schlegel, B., Gayoso, J., & Guerra, J. (2000). Manual de procedimientos. Muestreos de biomasa forestal. Retrieved from http://www.uach.cl/procarbono/pdf/manuales/guia_destructivo.pdf

Sigala, R. J. Á., González, T. M. A., & Jiménez, P. J. (2015). Análisis de supervivencia para una reforestación con Pinus pseudostrobus Lindl . en el sur de Nuevo León. Ciencia UANL, 18(75), 61-66. Retrieved from http://cienciauanl.uanl.mx/wp-content/uploads/2015/10/art.-del-pino.pdf

Velázquez, A., Durán, E., Mas, J. F., Bray, D., & Bocco, G. (2005). Situación actual y prospectiva del cambio de la cubierta vegetal y usos del suelo en México. In Consejo Nacional de Población (CONAPO) (Ed.), México ante los desafíos de desarrollo del milenio (pp. 391-412). México: CONAPO.

Figures:

Figure 1. Survival of Pinus leiophylla plants with different water reservoir treatments.
Figure 2. Survival of Pinus leiophylla plants with different water reservoir treatments.
Figure 3. Biomass of P. leiophylla under different water reservoir treatments. Bars with the same pattern and a different letter indicate statistically significant differences according to the Tukey test (P ≤ 0.05).

Tables:

Table 1. Water reservoir treatments applied at transplanting of Pinus leiophylla in a greenhouse.
Treatment Description Placement
T1 Control. No phenolic foam blocks The plant was placed in a traditional way
T2 Hydrated phenolic foam block of 3.3 x 7 x 10 cm and 231 cc dry volume The block was placed on one side of the plant root ball, at a depth of 7 cm below the surface
T3 Hydrated phenolic foam block of 4.4 x 7 x 10 cm and 308 cc dry volume The block was placed on one side of the plant root ball, at a depth of 7 cm below the surface
T4 3 g of hydrated hydrogel The hydrogel was dispersed around the root ball, at a depth of 5-7 cm
Table 2. Survival of different tree species by applying water reservoirs at transplanting.
Authors Species studied Days of survival
Control Hydrogel Phenolic foam
Agaba et al. (2010) Eucalyptus grandis W. Mill ex Maiden 24 40 -
Grevillea robusta A. Cunn. ex R. Br. 27 74 -
Maesopsis eminii Engl. 21 91 -
Melia volkensii Gürke 50 90 -
Pinus caribaea Morelet 32 59 -
Terminalia superba Engl. & Diels 21 76 -
Azadirachta indica A. Juss. 23 65 -
Araucaria cunninghamii Aiton ex D. Don 84 145 -
E. citriodora Hook. 42 50 -
Orikiriza et al. (2013) P. sylvestris L. 34 51 -
Picea abies (L.) H. Karst. 32 40 -
Fagus sylvatica L. 30 33 -
Present study Pinus leiophylla Schiede ex Schltdl. & Cham. 35 56 56
Table 3. Weekly survival of Pinus leiophylla under different water reservoir treatments.
Treatment Weekly survival (%)
1 2 3 4 5 6 7 8 9 10 11 12
Control 100.0 a 100.0 a 100.0 a 76.7 a 51.7 b 43.3 b 19.7 b 8.3 b 3.3 a 3.3 a 3.3 a 1.7 a
Phenolic foam (231 cc) 100.0 a 100.0 a 100.0 a 92.0 a 88.0 a 88.0 a 75.0 a 52.0 a 32.0 a 15.0 a 10.0 a 5.0 a
Phenolic foam (308 cc) 100.0 a 100.0 a 100.0 a 92.0 a 90.0 a 87.0 a 78.0 a 62.0 a 40.0 a 20.0 a 17.0 a 13.0 a
Hydrated hydrogel (3 g) 100.0 a 100.0 a 100.0 a 100.0 a 100.0 a 91.7 a 45.0 a 45.0 a 20.0 a 13.3 a 11.6 a 8.3 a
*Values in the same column followed by a different letter indicate statistically significant differences according to the Kaplan-Meier estimator (P = 0.000008).
Table 4. Analysis of covariance for the variables height and diameter with water reservoir treatments in Pinus leiophylla.
Variable Week after transplanting Mean squares Pr > F
Treatment (3)* Error (235)*
Height 8 7.77 5.63 0.250
Height 12 10.44 5.58 0.135
Diameter 8 1.68 0.45 0.013
Diameter 12 2.33 0.46 0.002
*Degrees of freedom for each source of variation are shown in parentheses.
Table 5. Variation in diameter of Pinus leiophylla in different weeks of evaluation.
Treatment Average diameter in week 8 (mm) Average diameter in week 12 (mm)
Control 3.92 b 3.96 b
Phenolic foam (231 cc) 4.21 a 4.31 a
Phenolic foam (308 cc) 4.04 a 4.20 a
Hydrated hydrogel (3 g) 4.29 a 4.44 a
Values in the same column followed by a different letter indicate statistically significant differences according to the Tukey test (P ≤ 0.05).
Table 6. Analysis of variance for the variables root, shoot and total biomass of Pinus leiophylla with water reservoir treatments.
Variable Mean squares Pr > F
Treatment (3)* Error (236)*
Root biomass 0.857 0.100 0.0001
Shoot biomass 3.954 0.625 0.0004
Total biomass 8.035 1.016 0.0001
*Degrees of freedom for each source of variation are shown in parentheses.