Virtual Plants: Modeling Plant Architecture in Changing Environments

Plant architecture is a major determinant of the resource use efficiency of crops. The architecture of a plant shows ontogenetic structural changes which are modified by multiple environmental factors: Plant canopies are exposed to natural fluctuations in light quantity and the dynamically changing canopy architecture induces local variations in light quality. Changing temperature conditions or water availability during growth additionally affect plant architecture and thus crop productivity, because plants have various options to adapt their architecture to the available resources. Meeting the challenge of ensuring food security we must understand the plant’s mechanisms for integrating and responding to an orchestra of environmental factors. ‘Virtual plants’ describe plant architecture in silico. Virtual plants have the potential to help us understanding the complex feedback processes between canopy architecture, multiple environmental factors and crop productivity. As a research tool, they have become increasingly popular within the last decade due to their great power of realistically visualizing the plant’s architecture. This Research Topic highlights current research carried out on modeling plant architecture in changing environments

LEAF PHYSIOLOGICAL AND ROOT MORPHOLOGICAL PARAMETERS OF GRAFTED TOMATO PLANTS UNDER DROUGHT STRESS CONDITIONS

Grafting of tomatoes becomes more and more popular particularly under adversarial soil conditions such as low and high soil temperature, salinity, alkalinity and drought. This study focused on the interactions between tomato rootstock and scion varieties regarding growth, development and yield under different water supply levels to identify the morphological and physiological plant traits related to drought tolerance of a tomato crop. Different tomato scion (S) varieties (Pannovy and Treasury) were grafted on different tomato rootstocks (R) (Brigeor and Maxifort) varieties and were grown under well watered (WW) and drought stress (DS) conditions. As control plants the S varieties were grafted on themselves. To evaluate growth and morphological effects, various plant parameters such as leaf area, fruit fresh matter, fruit diameter, main stem length, total plant dry matter, root fresh and dry matter, fruit water use efficiency (WUE), shoot WUE, total root length, root length density and root diameter were investigated at final harvest. To determine physiological plant traits, leaf water potential, leaf relative water content and leaf osmotic potential were assessed. Morphological parameters such as fruit fresh matter, fruit diameter, main stem length, total plant dry matter, fruit WUE, leaf area, root dry matter, total root length, and root length density were higher under WW than under DS conditions. As well, in terms of physiological plant parameters such as leaf relative water content (LRWC) was higher under WW than under DS conditions. Whereas, LRWC and leaf osmotic potential increased with increasing water stress. Generally, the self-grafted S varieties decreased their morphological parameters while an increase exhibited when they were grafted onto R varieties under DS condition. As a result of higher fruit WUE and shoot WUE the best performance in fruit fresh matter was shown by Pannovy/Brigeor combination under limited water supply levels

Impact of chitosan on shoot regeneration from faba bean embryo axes through its effect on phenolic compounds and endogenous hormones

Legume crops have been the primary targets for improvement by genetic transformation due to their importance for human and animal consumption worldwide. Many of these important legume crops were difficult to genetically engineer especially faba bean crop, mainly due to high phenolics content and their recalcitrance to in vitro regeneration. Therefore, a series of experiments were performed in order to evaluate the growth , morphological changes and production of phenolics in the in vitro plantlets of five Egyptian faba bean cultivars (Giza 843, Sakha 1, Sakha 3, Nubaria 2 and Nubaria 3). The obtained results revealed that cultivars Nubaria 2 and Skha 3 had the highest regeneration frequency (85.3% and 78.6%), respectively. Also, both cultivars showed high growth parameters and low in total phenols concentration. Therefore, these cultivars considered as promising candidates to Agrobacterium mediated genetic transformation experiments. The effect of different levels of chitosan (0, 2, 4, 8, 15, 30, 60, and 120 mg chitosan/l) on shoot regeneration from mature embryo axes of cv. Nubaria 2 were studied. The obtained results indicated that high levels of chitosan have lethal effect on the development of embryo axes tissues and the plantlets showed morphological abnormalities. However, low levels of chitosan 2 mg /l and 4mg /l in combination with 4.5 mg/l BAP increased the shoot regeneration. Moreover, the total soluble phenols were increased by increasing the age of the faba bean plantlets (six weeks old) cultured in vitro on a medium containing low level of chitosan (2, 4 and 8 mg chitosan/l) as compared with plantlets did not expose to chitosan. HPLC analysis showed changes in the polyphenols concentrations and the concentration of Gibberellic acid (GA3) and Abscisic acid (ABA) in faba bean plantlets that exposed to low levels of chitosan (2, 4 and 8 mg chitosan /l) were increased as compared with control plantlets. The obtained results indicated that the concentration of phenolic compounds, GA3 and ABA in the extracts were increased in the faba bean plantlets that exposed to low levels of chitosan.file: :Users/u0129515/Sync/My_list_publication/Abeer, 2020.pdf:pdf keywords: ABA,Embryo Axes,GA3,Phenols,Regeneration Frequenc