Aloes

A native of Bruges (now part of Belgium), Jacques de Coutre was a gem trader who spent nearly a decade in Southeast Asia in the early 17th century. In addition to a substantial autobiography written in Spanish and preserved in the National Library of Spain in Madrid, he wrote a series of memorials to the united crown of Spain and Portugal that contain recommendations designed to reverse the decline in the fortunes of the Iberian powers in Southeast Asia, particularly against the backdrop of early Dutch political and commercial penetration into the region. Translated into English for the first time, these materials provide a valuable first-hand account of the bigger issues confronting the early colonial powers in Southeast Asia, and deep insights into the societies De Coutre encountered in the territory that today makes up Singapore, Malaysia, Thailand and the Philippines.

Leaves of Aloe arborescens Mill. are a relevant source of secondary metabolites of pharmaceutical relevance. Notwithstanding, specialized cultivations of A. arborescens are still rather limited, and a straightforward agro-nomical research addressed to the obtainment of high-quality material is lacking. With the purpose to fill this gap, from 2016 to 2018, a trial was arranged to evaluate the growth and development of A. arborescens, along with the production of four active metabolites (aloin A and B, aloenin A, and isoaloeresin D) with varying some growth conditions. Two growth substrates ("A"-a commercial substrate, and "B"-the same substrate + 20 % perlite), two durations of pre-transplant open-air storage ("stress", 7 and 14 days), and 3 illumination levels obtained by means of shadow nets with different mesh dimensions (SL: full sunlight; T50: 50 % shading; T70: 70 % shading) were tested, combined in a factorial experimental layout with 3 repetitions. In general, light intensity was the most crucial experimental factor, whereas the effects of growth substrate and pre-transplant stress were scarce and limited in time. The addition of perlite to the growth substrate gave the best results in terms of leaf size and root growth, without any significant effect on the yield of active metabolites. The increasing shading level caused a parallel increase of several biometrical characters of plants (height, number of leaves per plant and mean diameter of the stem), whereas the number of suckers per plant was positively affected by the increase of illumination level. The illumination level was also responsible for significant variations in the content of all secondary metabolites, except for aloin A, that resulted statistically not different among the illumination treatments (from 0.80 to 0.98 % in dry matter). The content of aloenin A and aloin B was higher in the plants exposed in full sun, statistically well differentiated from those exposed to 70 % shadow (2.0 vs. 1.4 % d.m. aloenin A, and 1.12 vs 0.86 % d.m. aloin B, in full sun and 70 % shadow, respectively). Contrastingly, the highest levels of isoaloeresin D were reached in the two shaded treatments (4.98 % in 50 % shadow and 4.89 % in 70 % shadow), whereas the full sun treatment reached the lowest value. The higher number of leaves in plants exposed at reduced illumination, however, brought to increased total amounts per plant of aloin (A and B) and aloenin A with increasing shadow levels.

Aloe arborescens is a widespread and variable species, characterized as a much branched shrub 2–5m high by most authors. The remarkable single-stemmed, arborescent form endemic to Mount Mulanje (Malawi) has been largely ignored previously and is here described and illustrated in detail. In its vegetative and reproductive morphology, the arborescent form falls within the known range of variation, and is connected with the typical shrubby growth form by intermediates; it is considered a mere  variant not worthy of formal taxonomic recognition but unique in its deviating growth form. The arborescent form is mostly unbranched or sparsely branched, but may also form specimens with thick stems and a huge crown. Within the revised classification of Aloe based on molecular data, the tree-like species with massive stems and crowns such as A. dichotoma were classified in the segregate genera Kumara and Aloidendron, so that the tree-like specimens of A. arborescens as well as some specimens of the Tanzanian A. volkensii ssp. volkensii represent the sole truly tree-like specimens with massive stems and crowns within the genus Aloe as now circumscribed (Aloe s. str.). The arborescent form occurs mostly between huge boulders which give some shade to the plants, which might discourage stem branching due to a lack of strong light for part of the daytime, and it might cause a micro-climate of cold air to accumulate between the rocks which might inhibit growth, in addition to protection from strong winds and frost.

Exploratory botanical expeditions to three remote and little-known regions of Madagascar have resulted in the discovery of three new species of Aloe, a diverse genus of leaf-succulent perennials with a rosulate habit, leaves typically armed with marginal teeth, and united (rarely completely free) perianth segments that are fleshy and brightly colored. The new species are: Aloe analavelonensis from humid forest on the Analavelona Massif northeast of Toliara; Aloe beankaensis from the Beanka Forest and Tsingy de Bemaraha, both dry forests on tsingy limestone in the west; and Aloe ivakoanyensis from humid forest on the Ivakoany Massif in the southeast. The sectional placement of A. analavelonensis is uncertain but the other two new species belong to section Lomatophyllum, an assemblage of some 19 species with fleshy semi-dehiscent fruits that is largely restricted to Madagascar and some Mascarene Islands. These new species are described, mapped, illustrated, and compared with presumed relatives. We also evaluate the conservation status of each species in the context of IUCN Red List guidelines and criteria

Nucleolar organizing region of eight species of Aloe was analyzed in somatic metaphases and interphase nuclei. All species showed a uniform 2n=14, with eight large chromosomes and six small chromosomes. Satellites were observed on the long arm of one or two pairs of large chromosomes and/or on the short arm of one of the small pairs. The silver-stained nucleolus organizing regions were located on the subtelomeric region of the long arm of one or two pairs of large chromosomes, except for Aloe dichotoma and Aloe maculata, which the AgNORs were located at a short arm of one of their small chromosomes. In most studied species, the active AgNOR number was four. However, this number changing from one to eight. For all species, the interphase number of nucleoli can be one or two, while, in Aloe excelsa, this number can be changing from one to eight. Polymorphism of active AgNORs and the number of interphase nucleoli were revealed, except for Aloe petricola, which active AgNORs were located only in the subtelomeric regions at the long arm of one of the L 2 chromosomes, as well as in the L 4 pair, which is agreement with the maximum number (three) of interphase nucleoli. Resumo A região organizadora nucléica de oito espécies de Aloe foi analisada em metáfases somáticas e núcleos interfásicos. Todas as espécies apresentaram um número uniforme de 2n = 14, com oito cromossomos grandes e seis pequenos. Satélites foram observados no braço longo de um ou dois pares de cromossomos grandes e/ou no braço curto de um dos pares pequenos. As regiões organizadoras del nucléolo coradas com prata estavam localizadas na região subtelomérica do braço longo de um ou dois pares dos cromossomos grandes, exceto en Aloe dichotoma e Aloe maculata, em que os AgNORs estavan localizados em um braço curto de um de seus cromossomos pequenos. Na maioria das espécies estudadas, o número ativo de AgNOR era quatro. No entanto, esse número muda de um para oito. Para todas as espécies, o número de nucléolos na interfase pode ser um ou dois, enquanto, em Aloe excelsa, esse número pode estar mudando de um a oito. Polimorfismo de AgNORs ativos e o número de nucléolos em interfase foram revelados, exceto Aloe petricola, cujos AgNORs ativos estavam localizados apenas nas regiões subteloméricas no braço longo um dos cromossomos L2, bem como no par L4, concordando com o número máximo (três) de nucléolos em interfase. Palavras-chave: Aloe, AgNORs, atividade nucleolar, bandeamento de prata.

In this study the possibility of using a biostimulant based on Glomus deserticola to improve the growth and quality of Gasteraloe plants and protection against Fusarium sp. was evaluated. Objectives of the work were: i) use Glomus deserticola to assess whether the use of this Arbuscular mycorrhizal fungi can increase the growth rate of Gasteraloe plants generally slow in their growth cycle; ii) consider if the use of Glomus deserticola can lead to an increase in plant resistance under saline substrate conditions; iii) evaluate how the use of Glomus deserticola allows greater protection of plants from Fusarium sp. which often affects the roots of these succulents. The four experimental groups in cultivation were: i) group without Glomus, irrigated with water and substrate previously fertilized; ii) group without Glomus, irrigated with salt water (0.50 g of NaCl Kg-1 dry soil) and substrate previously fertilized; iii) group with Glomus deserticola, irrigated with water and substrate previously fertilized; iv) group with Glomus deserticola, irrigated with salt water (0.50 g of NaCl Kg-1 dry soil) and substrate previously fertilized. The test showed a significant increase in agronomic parameters analyzed in plants treated with Glomus deserticola on Gasteraloe cv. Magica and Gasteraloe aristata x platinum. The test also highlighted how the use of mycorrhizae in particular of Glomus spp. can determine a greater resistance against salt stress and greater protection against attacks of Fusarium sp. The application of mycorrhizae in the cultivation of succulent plants guarantees growers the possibility of obtaining a superior quality product, greater resistance to biotic and abiotic stress, an increase in the growth rate and mineral content of the tissues, aspects that are then found in the improvement of the quality of the plants and consequently their commercialization.

Resumen Se estudia el cariotipo de tres especies de Aloe con bandeo cromosómico C-Giemsa, CMA (Cromomicina A 3) y DAPI (4'–6-diamino-2.fenildol), con la finalidad de realizar aportes en su cariomorfometría, ubicación, tamaño de bandas, y discutir evidencias citogenéticas sobre el origen híbrido reportado en A. x spinossisima. Las entidades estudiadas presentan un 2n = 2x = 14 con dos pares de NORs (regiones organizadoras del nucléolo) con satélites asociados y heterocromatina constitutiva CMA + DAPI-(zonas ricas en G-C). La cantidad de heterocromatina, expresada en % de la longitud total del cariotipo (LTC), varía entre las especies: 1,92% en A. arborescens, 1,69% en A. humilis y 1,41% en A. x spinossisima. Se observan bandas en los brazos largos de L 2 y L 4 de A. arborescens, en L 3 y L 4 de A. humilis y en A. x spinosissima en el par L 4 y en uno de los complementos de L 2 y uno de L 3. A. x spinossisima presenta valores de la LTC haploide y cantidad de heterocromatina constitutiva, intermedios entre las especies señaladas como progenitoras. Estos resultados y la notoria heteromorfía entre los diferentes pares cromosómicos, refuerzan la hipótesis del origen de A. x spinosissima, como especie híbrida proveniente del cruce natural de A. arborescens x A. humilis. Abstract The karyotype of three species of Aloe was studied with C-Giemsa, CMA (Chromomycin A 3) and DAPI (4'–6-diamino-2.fenildol) chromosome banding in order to make contributions in their cariomorfometría, location, size studied bands, and discuss cytogenetic evidence of hybrid origin reported in A. x spinossisima. The entities studied have a 2n = 2x = 14 with two pairs of NORs (nucleolar organizer regions) with associated satellites and constitutive heterochromatin CMA + DAPI-(G-C rich regions). The amount of heterochromatin, expressed in % of the total length of the karyotype (LTC), varies between species: 1.92% by A. arborescens, 1.69% in A. humilis and 1.41% in A. x spinossisima. The bands are observed in the long arms of L 2 and L 4 of A. arborescens, in L 3 and L 4 of A. humilis and A. x spinosissima in the pair L 4 and one of the supplements L 2 and L 3 one. A. x spinossisima presents values of LTC haploid and amount of constitutive heterochromatin intermediate between species designated as progenitor. These results and the notorious heteromorphy between different chromosome pairs, supports the hypothesis of the origin of A. x spinosissima, as a hybrid species from the natural crossing of A. arborescens x A. humilis.