EFFICIENCY OF THE USE OF WATER BY THE LEAVES OF SOY PLANTS: TRADITIONS AND NEW CRITERIA

The aim of the study was to assess the traditional and new criteria for evaluating water use efficiency (WUE) of soybean leaves by comparing different parameters from instantaneous measurements (WUEi) with the WUE at the field level, as well as studying WUEi-parametres in daily dynamics. Studies were performed using photosyn-thesis and transpiration rate monitor PTM-48A to soybean plants (variety Amelina) in pots with sufficient water supply. It was concluded that as close as possible to WUE field value (0,80 g seeds per kg H2O) is the evaluation of the WUEias a ratio of respiration per unit of water transpired. Estimation of leaf WUEiaccording to previously known parameters does not correspond to field level WUE

Impacts of the dry season on the gas exchange of oil palm (Elaeis guineensis) and interspecific hybrid (Elaeis oleífera x Elaeis guineensis) progenies under field conditions in eastern Colombia

Elaeis guineensis palms and its interspecific hybrid (E. oleifera x E. guineensis) were planted in 2004 in the Cuernavaca farm of Unipalma S.A., located in the municipality of Paratebueno (Cundinamarca, Colombia). The palms were planted in two fields: Mecasaragua and Aurora. The first field has never been irrigated, and the second one (Aurora) has always been flood-irrigated during the dry season according to the parameters of the plantation. In this study, physiological parameters (gas exchange and water potential) were assessed in three seasons of the year 2013 (dry season, dry-to-wet transition season and wet season). Significant gas exchange differences were found among the seasons in the field with no irrigation (Mecasaragua). Likewise, differences between the genetic materials were observed during the dry season. For example, the photosyn thesis decreased by 75% compared with the palms planted in the irrigated field. No differences among seasons or materials were found in the irrigated field (Aurora). E. guineensis palms were more sensitive to water stress compared with the OxG interspecific hybrid. Both genetic materials responded rapidly to the first rains by leveling their photosynthetic rates and demonstrated an excellent capacity to recover from water stress.

Photosynthesis and the role of plastids (kleptoplastids) in Sacoglossa (Heterobranchia, Gastropoda): a short review

Title (Bahasa Indonesia): Fotosintesis dan peran plastida [kleptoplastids] pada Sacoglossa [Heterobranchia, Gastropoda]: tinjauan singkat. In this manuscript I will give a short summary of our knowledge on photosyn-thesis in the enigmatic gastropod group Sacoglossa. Members of this group are able to sequester chloroplasts from their food algae (mainly Chlorophyta) and store them for weeks and months and it was assumed for a long time that they can use chloroplasts in a similar way as plants do. Only few sacoglossan species are able to perform photosynthesis for months, others are less effective or are not able at all. The processes involved are investigated now for a few years, but are still not clear. However we know now that many factors contribute to this enigmatic biological system. These include extrinsic (environment, origin and properties of the nutrition and the plastids) and intrinsic factors of slugs and algae (behaviour, physiological and anatomical properties). Plastids are not maintained by genes that might have originated by a horizontal gene transfer (HGT) from the algal genome into the slug genome, as was hypothesized for many years. We therefore have to focus our research now on other factors to understand what actually contributes to this unique metazoan phenomenon which is not yet understood. In this review, some of these new approaches are summarized. Dalam tulisan ini saya akan memberikan ringkasan singkat tentang fotosintesis pada gastropoda kelompok misterius Sacoglossa. Organisme anggota dari kelompok ini mampu menyerap kloroplas dari alga makanan mereka (terutama Chlorophyta) dan menyimpannya selama berminggu-minggu, bahkan berbulan-bulan, sehingga telah diasumsikan bahwa mereka dapat menggunakan kloroplas dengan cara yang sama seperti tanaman. Hanya sedikit spesies sacoglossan dapat melakukan fotosintesis selama berbulan-bulan, yang lain kurang efektif atau tidak mampu sama sekali. Proses yang terlibat diselidiki sekarang selama beberapa tahun, namun masih belum jelas. Namun kita tahu sekarang bahwa banyak faktor yang berkontribusi terhadap sistem biologis misterius ini. Ini termasuk ekstrinsik (lingkungan, asal dan sifat gizi dan plastida) dan faktor intrinsik siput dan ganggang (perilaku, fisiologis dan sifat anatomis). Plastida tidak dikelola oleh gen yang mungkin berasal oleh transfer gen horizontal (HGT) dari genom alga ke dalam genom slug, seperti yang dihipotesiskan selama bertahun-tahun. Oleh karena itu kita harus fokus penelitian kami sekarang pada faktor-faktor lain untuk memahami apa yang sebenarnya memberikan kontribusi terhadap fenomena ini metazoan unik yang belum dipahami. Dalam ulasan ini, beberapa pendekatan baru dirangkum.