Evaluation of Growth Parameters on Carpobrotus edulis, Kalanchoe daigremontiana and Kalanchoe tubiflora in Relation to Different Seaweed Liquid Fertilizer (SLF) as a Biostimulant

The aim of this research was to evaluate the biofertilization capacity of five different species of algae, representative of the three main groups of macroalgae selected from Lake Ganzirri in Messina, Venice Lagoon and Norwegian coasts. The experiments, started in January 2021, were conducted in the greenhouses of CREA-OF in Pescia (Pt), Tuscany, Italy (43°54′N 10°41′E) on Carpobrotus edulis, Kalanchoe daigremontiana and Kalanchoe tubiflora from seed. The test showed a significant increase in the agronomic parameters analysed in plants treated with algae extracts on succulents cultivated. The test also showed increased control of the pathogen Pythium debaryanum in seedlings where the algae extracts were introduced and also an increase in the percentage of seed germination and a reduction in the average germination time. This research work has shown that algal species have great potential for use in the development of biofertilisers in sustainable agriculture in terms of cost-effectiveness, ecological role, possible reduction of synthetic fertilisers and plant protection products, increased soil fertility and microbiological diversity.

Impact of colchicine on leaf morphology and stomatics of Kalanchoe tubiflora (Harv.) Raym.-Hamet (Crassulaceae)

The demand of medicinal plants for consumption is greatly increasing worldwide. The conventional breeding programs are generally dependent on the environment prone to biotic and abiotic stresses. These added to the low content of secondary metabolites at harvest, bring the need for artificial development of polyploid individuals as an alternative to increase productivity. Consequently, the present study evaluated the effect of different colchicine concentrations and exposure time, on Kalanchoe tubiflora leaf morphology and stomata. Initially, K. tubiflora seedlings were harvested and submitted to colchicine concentrations of 0, 0.025, 0.05 and 0.1 % and at two exposure times (24 and 48 hours). Subsequently, morphological measurements such as plant height, leaf width, leaves number, leaf length, leaf thickness and leaf volume every 15 days were made for 16 weeks after planting. Then, the stomata were characterized, taking into account the width, length, stomatal index and the number of chloroplasts per stoma. A significant increase in leaf morphology was found in colchicine treatments of 0.025 % at 48 h and 0.1 % at 24 h. A significant increase in stomatal morphology with the treatment of 0.025 % at 24 h was also recorded. This shows that the correct application of colchicine in term of quantity and time could produce greater growth in a short period and increase the biomass of K. tubiflora medicinal plant.

Trichoderma viride inoculated in the growing medium for the vitamin C increase in the leaves of Kalanchoe spp. and defense against Pithyum sp.

The article presents the results of research on succulents such as Kalanchoe pinnata, Kalanchoe tubiflora and Kalanchoe gastonis-bonnieri, aimed at improving plant growth and defense against the pathogenic fungus Pythium sp., through the use of Trichoderma viride inoculated in the medium. Objectives of the work were: 1) use Trichoderma viride to assess whether the use of this endophytic fungus can increase the growth rate of Kalanchoe pinnata, Kalanchoe tubiflora and Kalanchoe gastonis-bonnieri, plants generally slow in their growth cycle; 2) evaluate if using Trichoderma viride can lead to an increase in vitamin C content in the leaves of Kalanchoe spp.; 3) assess and evaluate how the use of Trichoderma viride allows greater protection of the roots from Pithyum sp. which often affects the roots of these succulents. The two experimental groups in cultivation were: i) group without Trichoderma spp., irrigated with water and substrate previously fertilized; ii) group with Trichoderma viride, irrigated with water and substrate previously fertilized. The test showed a significant increase in agronomic parameters analyzed in plants treated with Trichoderma viride. In fact, all plants treated showed a significant increase in height and number of leaves per plant, vegetative and root weight of plants, number and weight of new shoots, total number of germinated seeds/ 100 seeds sown and a significant reduction in average germination time. In addition, plants treated with Trichoderma show an increase in leaf vitamin C content, dry mass and a reduction in plant mortality due to Pythium sp. Tricoderma can also optimize the use of fertilizers and water by facilitating the cultivation of plants in certain locations subject to biotic and abiotic stress.

Three Bufadienolides-Induced Human Lung Cancer CL1-5 Cell Death Mainly through Autophagy

Lung cancer is almost the most common cause of cancer death in the world. Clinically, the conventional therapy to eradicate the cancer cells is chemotherapy but a better drug remains required. In this study, the effects of three bufadienolides, kalantuboside B, kalantuboside A and bryotoxin C, isolated from Kalanchoe tubiflora (Harvey) were evaluated and characterized in CL1-5 highly metastatic human lung cancer cells. Contrary to the apoptosis-promoting activity in other cancer cells, these three bufadienolides did not induce apoptosis in CL1-5 cancer cells. Instead, they activated an autophagy pathway, as indicated by the increase of autophagosomes formation. The induction of autophagy by these three bufadienolides was demonstrated to link to down-regulation of p-mTOR as well as up-regulation of LC3-II, ATG5, ATG7, Beclin-1. Moreover, among these three compounds, kalantuboside B in which a monosaccharide is attached at the bufadienolide aglycon, exhibited a better autophagy induction. Our findings revealed an alternative mechanism of drug action by bufadienolides in lung cancer cells and provided evidence for the possibility of treating highly metastatic human lung cancer through an autophagy pathway.

Water loss prevention plays a greater role than ROS scavenging in dehydration tolerance of Kalanchoe tubiflora epiphyllous buds

Different plants and plant organs have various strategies to cope with drought stress.Kalanchoe tubifloraplants have a strong ability to prevent water loss and to scavenge reactive oxygen species. The epiphyllous bud of the plant serves as a reproduction unit and is able to generate plantlets even under conditions of extreme drought. The aim of this project was to study the antioxidant-stress response and osmoregulation ofK. tubifloraepiphyllous buds to dehydration and to compare the drought-tolerance mechanisms of the plant body and the epiphyllous buds. With the progression of bud dehydration, relative water content, seedling survival rate and dry weight per seedling decreased, and electrolyte leakage, hydrogen peroxide and malondialdehyde content and superoxide anion production rate increased. The activities of the antioxidant enzymes superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase decreased under dehydration. The content of proline, soluble sugars and soluble protein increased in dehydrated buds proportionally with the extent of water loss. These data indicate that the drought-tolerance mechanism of theK. tubiflorabud was different from that of its mother plant. The buds invest more energy to prevent water loss during drought stress, and their antioxidant defense weakens.