When the great pandemic caged us inside the walls, hunkering down indoors made good sense whereas in global scenario no one has escaped from the impact of pandemic also it has triggered 25 per cent increase in the prevalence of anxiety and depression among human beings (
WHO, 2022). This fact is considered as a wake-up call to all countries to set up better mental health services and human welfare. The pandemic COVID-19 had generated some interest in and concern for the mental health. Also, it has revealed the world about the historical under-investment in the mental health services, thus it is the high time for countries to act urgently to ensure the mental health of their citizens.
The renowned psychologist Erich Fromm introduced the term ‘Biophilia’ which means ‘attraction towards the nature’ yes, the genetically predetermined habit of gazing the nature automatically pacifies the soul and mind of human beings as because the mankind was born and bonded with the nature. The solution to reduce the anxiety and stress cannot be achieved by eliminating nature or by isolating our lives from nature (
Koay and Dillion, 2020). Opening the windows and allowing the nature to extend its branches from outdoor to indoor may be one of the best options to be considered for calming our soul. Here comes the concept of ‘Bio-walls’ which is otherwise called as ‘living walls’ the simplest and versatile component in gardening which requires minimal space and less maintenance that reinforce eco-friendly interiors, reduces CO
2 emission, improves air quality and soothes human mind (
Dedhia, 2022 and
Rodiek, 2022).
The plant
Vernonia elaeagnifolia DC is considered as the best suited plant for Bio walls. It is an extensive perennial, woody, ornamental climber. The plant is grown as an ornamental plant in houses and gardens especially on fencing compound walls and buildings which reaches up to 7-8 m in height. It is a popular climber for screening. As the slender stems finds it difficult to climb without support, they climb up and then fall beautifully over a wall or railing forming a curtain hence the name curtain creeper. It is a foliage plant grown primarily for its habit of forming green curtain. The plants are evergreen and prefers full sunlight and water requirement is little and the growth rate of the plant is fast. The plant is propagated by stem cuttings and as the plant matures it changes its colour from green, silver and grey.
The stems are observed to be very tender; the propagation and maintenance of this creeper seems to be difficult and the research on this creeper is scarce. In view of the above, present study entitled ‘Clonal propagation of
Vernonia elaeagnifolia DC’ was attempted to find out the best propagating technique for the creeper which may help in improving the maintenance of the plant, also by standardizing the techniques, the use of this creeper in the bio walls can be improved which may help us in creating an eco-friendly building and adds aesthetic sense to the surroundings.
A study entitled ‘Clonal propagation of
Vernonia elaeagnifolia DC was carried out to develop a suitable propagation technology for the large-scale production through stem cuttings in Vernonia under mist chamber condition at SRM UFC, SRMIST, Kattankulathur during the period 2021-2022 (Fig 1).
Treatment details
The softwood cuttings of Vernonia were collected from three-year-old plant and the experiment was tried to elucidate the impact of various cutting diameter as 1 to 1.5 cm, 2 to 2.5 cm and 3 to 3.5 cm in the mist chamber as T
1, T
2 and T
3, respectively. Shoot sprouting and rooting with uniform exogenous application of growth regulator were analyzed. The rooting media, sandy soil and Farmyard manure were mixed thoroughly and cleaned for stones and grasses and the mixture was filled in the beds. The basal ends of the cuttings were dusted with rootex powder as quick dip method for 10 seconds before planting in the rooting medium. The treated cuttings were planted carefully in the beds with a depth of 5 cm in the medium. The completely randomized design (CRD) is imposed with ten replications and the data were recorded for four different growth parameters of Vernonia.
Field observations and statistical analysis
The softwood cuttings of Vernonia plant with different diameter in size collected, were propagated and different observations like stem thickness (cm), stem length (cm), number of roots, maximum root length (cm), minimal root length (cm), number of leaf branches from nodes were recorded after 30th day of planting and the all the data obtained from the experiment were statistically analyzed by following standard ANOVA procedures.
The results pertaining to stem characters
viz., stem thickness, stem length and number of leaf branches were recorded from the study (Fig 2). The data related to stem thickness reveals that, the highest mean was observed as 3.2 cm in the T
3 followed by T
2 and T
1 which showed the mean values as 2.15 and 1.3 cm, respectively. The mean stem length of 20 cm was recorded in the T
1 followed by T
2 and T
3 in which, the mean value was 16.7 and 14 cm, respectively. The number of branches in the softwood cuttings of Vernonia showed the mean values as 2.8, 2.4, 2.4 in the treatments T
2, T
3 and T
1, respectively (Fig 3 and 4).
Various root parameters like number of roots, maximum root length and minimum root length were recorded in the study in which the highest mean value of number of roots as 34, 14, 7 and maximum root length as 10.1, 8.3, 5.8 cm was recorded in the T
3 followed by T
2 and T
1, respectively. In the three treatments, the mean value for minimum root length was recorded as 1.35, 3.1 and 3.65 cm in the treatments as T
1, T
3 and T
2, respectively (Fig 3 and 4). It is evident that the softwood cuttings with T
3 significantly recorded higher values of different growth parameters of Vernonia followed by the T
2 and T
1.
Chaturvedi (2001) recorded that the presence of increased levels of auxins, higher levels of carbohydrates, higher C:N ratio and reduced levels of the inhibitory substances were observed in the thicker cuttings of different plants in comparison to the thinner cuttings and these attributes in the thicker cuttings recorded significantly higher rooting characters in the thicker cuttings and similar findings were reported by
Singh et al., (2011); Damar et al., (2014); Mehta et al., (2018) and
Singh et al., (2021).
In tree species, significantly more leaves were observed in matured basal cuttings than the tender apical cuttings
(Soundy et al., 2008). Kesari et al., (2009) recorded that in which they have recorded that the in the mature stem cuttings of
Pongamia pinnata, presence of higher levels of auxins and carbohydrates influenced the adventious.
Dvin et al., (2011) observed that in the matured cuttings of apple clonal rootstocks, the maximum root length was recorded by treating it with IBA.
Similar results were reported by
Mishra and Kumar (2014) where the mature cuttings of
Commiphora wightii showed better results by placing in the mist chamber. It may be due to the maintenance of humidity levels that is been maintained in the area surrounding to the plants greatly influenced the different plant growth traits through balancing the transpiration, water level and cooling of plants. Better results were observed by placing the plants in mist chamber where the plants are exposed to lower radiation and higher humidity.
A significant influence of rooting of cuttings was observed in the stem cuttings with higher diameter in the apple clonal rootstock by
Verma et al., (2015). The presumably increased number of nodes, development of additional leaves and shoot growth development in the thicker cuttings were recorded by the influence of higher IBA level in plants which might have enhanced the cell division and elongation in plants (
Singh and Negi, 2014,
Debi, 2022 and
Rao et al., 2022).
The data recorded in this study reveals that the presence of different growth promoting parameters in the softwood cuttings
viz., IAA, IBA, carbohydrates, C:N ratio, lesser inhibitory substances
etc., were significantly higher in the cuttings of higher diameter when compared with lower diameter and this might influence the better rooting patterns and shoot growth parameters in the Vernonia plants with softwood cutting diameter of 3 to 3.5 cm.
