**3.5 Assessing the growth performance of the** *Bothriocline auriculata* **species, and its response to abiotic stress under different conservation management schemes and environments**

Availability of high-quality seedlings that are disease-free, fast-growing, biotic and abiotic stress-tolerant and are genetically identical to the parent species is one of the primary challenges facing the conservation biologists and forest nursery operators in Uganda. As such, the lack of a reliable supply of quality seedlings for the threatened and most critically endangered species such as *Bothriocline auriculata* species makes them get excluded from the local species restoration, conservation and adaptive management programs such as agroforestry, forest nurseries, parks, plant genetic resources, gene banks and forest ecosystems.

In response, quality seedlings of the critically-endangered *Bothriocline auriculata* species were produced in an aseptic (disease-free environment in the lab) using micro-propagation and tissue culture protocols at Makerere University (**Figure 4**). After tissue culture and micropropagation, the juvenile *Bothriocline auriculata* species seedlings were transplanted into PE-plastic pots for hardening. During hardening, the potted seedlings were irrigated with distilled water for about 5 weeks under culture room conditions in a screen house. The growth performance parameters were root collar diameter and shoot height.

The growth performance of the seedlings was studied in the screen house under artificial conditions namely, lighting, watering and growth media. **Table 2** shows a summary of the growth performance of the seedlings in response to the abiotic conditions of the growth media.

The growth performance parameters, namely shoot height, root collar diameter and number of leaves per seedlings increase with increasing duration as well as bulk density of the soil media and soil moisture level (**Table 2**).

The results suggest a normal seedling growth rate of the *Bothriocline auriculata* species under favorable growth media soil biophysical conditions; as represented by soil moisture and artificial lighting) in the screen house. Out planting success of plant


#### **Table 2.**

*Growth rate of the* Bothriocline auriculata *species seedlings.*

#### **Figure 5.**

*Variations in the growth rate of the seedlings (shoot height) for the Bothriocline auriculata species seedlings under screen house conditions with: i) normal soil moisture and ii) moisture deficient.*

species depends on several species' interaction between light, soil moisture other ecological conditions [13]. It has also been argued that the phenotypes of different plant species are characterized by morphological and physiological attributes, and are hence more important in predicting species-specific survival and growth during ex-situ conservation [15].

Conversely, the *Bothriocline auriculata* species seedlings were also subjected to stressful conditions to ascertain their growth response under soil moisture deficient conditions. The growth response of the species seedlings under both normal soil moisture and soil moisture deficient conditions were analyzed. The results describing the growth of the seedlings in terms of shoot length and root collar diameter are given, by a comparative approach (**Figure 5**).

Under optimum light and soil moisture conditions in a screen house, the growth rate (shoot height) of the *Bothriocline auriculata* species seedlings exponentially increases with time from the 1st week and attains a peak growth rate after the 5th week. The results suggest that the *Bothriocline auriculata* species complete the juvenile seedling growth cycle just after 1 month from sowing in appropriate soil media. On the contrary, the growth rate of the *Bothriocline auriculata* species seedlings declines rapidly with increasing deficiency of the soil moisture in the growth media. The data/results further confirm the high susceptibility of the *Bothriocline auriculata* species seedlings to abiotic stress conditions in the soil ecosystems. The results are consistent with the findings of IUCN [7] and [17]; who also reported positive correlational relationships between growth rate, soil moisture, temperature and other abiotic ecological conditions.

Nonetheless, the growth performance of the *Bothriocline auriculata* species was only assessed at the screen house level. Performance at the greenhouse and field level in the different ecosystems was NOT done due to a gap in funding. To this end, only 150 seedlings were regenerated enough for only replicate trials in the screen house. The data collected for the species growth performance was inconclusive because it did NOT include greenhouse conditions and under natural ambient weather and other environmental conditions in the fields. Therefore, future studies and efforts should focus on assessing the growth performance of the *Bothriocline auriculata* species seedlings beyond the artificial screen house conditions but rather under the natural ecological conditions; where the species will undergo ex-situ conservation in protected ecosystems and/or adaptive management in the agro-ecosystems.

*Integrated Conservation Approaches for Rescuing, Regeneration and Adaptive Management… DOI: http://dx.doi.org/10.5772/intechopen.106893*
