Arbuscular mycorrhizal fungi improve photosynthetic energy use efficiency and decrease foliar construction cost under recurrent water deficit in woody evergreen species

Plants suffer recurrent cycles of water deficit in semiarid regions and have several mechanisms to tolerate low water availability. Thus, arbuscular mycorrhizal fungi (AMF) can alleviate deleterious effects of stress. In this study, Cynophalla flexuosa plants, a woody evergreen species from semiarid, when associated with AMF were exposed to two consecutive cycles of water deficit. Leaf primary metabolism, specific leaf area (SLA), leaf construction cost (CC) and photosynthetic energy use efficiency (PEUE) were measured. The maximum stress occurred on seven days (cycle 1) and ten days (cycle 2) after suspending irrigation (photosynthesis close to zero). The rehydration was performed for three days after each maximum stress. In both cycles, plants submitted to water deficit showed reduced gas exchange and leaf relative water content. However, Drought + AMF plants had significantly larger leaf relative water content in cycle 2. At cycle 1, the SLA was larger in non-inoculated plants, while CC was higher in inoculated plants. At cycle 2, Drought + AMF treatment had lower CC and large SLA compared to control, and high PEUE compared to Drought plants. These responses suggest AMFs increase tolerance of C. flexuosa to recurrent water deficit, mainly in cycle 2, reducing the CC, promoting the improvement of SLA and PEUE, leading to higher photosynthetic area. Thus, our result emphasizes the importance of studies on recurrence of water deficit, a common condition in semiarid environments.

Protective action of Crateva nurvala Buch. Ham extracts against renal ischaemia reperfusion injury in rats via antioxidant and anti-inflammatory activities

ETHNOPHARMACOLOGICAL RELEVANCE

Crateva nurvala stem bark is commonly used in Ayruveda in treatment of many renal injuries, e.g., urinary lithiasis, diuretic and nephroprotective. However, its protective effect against renal ischaemia/reperfusion, the major cause of acute kidney injury, has never been studied. Moreover, no comprehensive chemical profiling of its extracts was recorded.

AIM OF THE STUDY

Assessment of the protective effect of the plant extracts against renal ischaemia/reperfusion and elucidation of the possible mechanism of action. Then, to determine its bioactive constituents using modern UPLC-HRMS technique.

MATERIAL AND METHODS

Unilateral ischaemia was induced by clamping the left renal artery for 1h then reperfusion for 24h. Rats were divided in 4 groups: i) sham-operated group, ii) ischaemia/reperfusion, I/R group, iii) I/R protected by previous administration of Crateva leaves extract, CLE group and iv) I/R protected by previous administration of Crateva bark extract, CBE group. At the end of reperfusion, blood samples were analyzed for renal function biomarkers. Kidneys were examined histopathologically and their homogenates were used in determining the intracellular levels of oxidative stress, inflammatory, and apoptosis markers.

RESULTS

Leaves and bark extracts attenuated the deleterious effects of I/R apparent in reducing LDH, creatinine and blood urea nitrogen levels. The extracts reduced the oxidative stress by replenishing the glutathione levels and Nrf2 factor levels. Moreover, extracts decreased levels of pro-inflammatory TNF-α, NF-κβ and IL-6; which ultimately resulted in reducing the pro-apoptotic caspase-3. Bark and leave extracts have quite similar chemical profile where 42 compounds of various chemical classes were identified. Flavonoids are the major class of the bioactive phytochemicals CONCLUSION: C. nurvala extracts had effectively ameliorated the deleterious effects of renal I/R by mainly counteracting oxidative stress and presumably inflammation. Consequently, it can be used as a complementary treatment with other agents. In this aspect, leaves stand as a sustainable alternative to bark. The presented chemical profiling can be used in future standardization and quality control of the drug.

Establishment of an in vitro micropropagation protocol for Boscia senegalensis (Pers.) Lam. ex Poir

This report describes in vitro micropropagation of Boscia senegalensis, so-called famine foods, that helped the people in Darfur and Kordofan, Sudan survive during the 1984-1985 famine. Four types of explants prepared from green mature zygotic embryos were cultured on Murashige and Skoog (MS) medium augmented with 1-5 mg/L 6-benzyladenine (BA). The highest number of shoots per explant (14.3±0.9) was achieved on MS medium supplemented with 3 mg/L BA, while the highest shoot length [(3.5±0.4) cm] was obtained with 1 mg/L BA. The shoot cluster, when subcultured to its same medium, significantly increased the rate of shoot multiplication by the end of the third subculture. The maximum mean number of shoots per explant (86.5±3.6) was produced after three multiplication cycles on 3 mg/L BA-supplemented medium. In vitro induced shoots were excised and rooted on half strength MS medium fortified with 0.25 mg/L indole-3-butyric acid (IBA) to obtain complete plantlets. B. senegalensis-regenerated plantlets obtained in vitro for the first time, were hardened and 95% survived under greenhouse conditions.

Large-scale in vitro multiplication of Crataeva nurvala

Conservation and propagation of species using biotechnologic tools-such as plant tissue culture-are relevant when natural propagation is hampered for various reasons. In vitro techniques allow mass multiplication and propagation under pathogen-free conditions but also override dependence on season for availability of plant material. Moreover, in vitro genetic manipulation of a species, invariably, requires a prestandardized tissue culture protocol for its multiplication.To fulfill these requirements, efficient, cyclic, two-step protocols for micropropagation of the medicinal tree-Crataeva nurvala-employing juvenile explants and those from mature trees, were developed. Both protocols can be employed at commercial scale. The seedling-derived explants (e.g., cotyledonary nodes, epicotyl nodes, hypocotyl segments, first pair of leaves, cotyledons, and root segments) developed shoots on Murashige and Skoog's (MS) or the same supplemented with different concentrations of 6-benzylaminopurine (BAP). The epicotyl and cotyledonary nodal explants developed shoots on MS basal medium. Other explants exhibited caulogenesis on BAP (0-2.0 mg/L) adjuvated media. The explants from in vitro regenerated shoots too exhibited a similar caulogenic capability. Nodal explants from a 30-yr-old-tree, when cultured on MS medium supplemented with 0.5 mg/L BAP, produced multiple shoots which elongated satisfactorily on the same medium. Similar to the microshoots developed from the seedling derived explants, nodal and leaf explants from the microshoots regenerated from the mature explants too developed shoots, thus making the process recurrent. Due to the recurrent nature of the protocol, over 5400 shoots may be produced from a single nodal explant of an adult tree over a period of six months. The addition of casein hydrolysate significantly increased the average number of shoots per explant. The regenerated shoots could be rooted on the medium supplemented with 0.02 mg/L or 0.1 mg/L NAA (alpha-naphthalene acetic acid). Regenerated plantlets were acclimatized and successfully transplanted to soil.