Physiology of medicinal and aromatic plants under drought stress

Drought poses a significant challenge,restricting the productivity of medicinal and aromatic plants.The strain induced by drought can impede vital processes like respiration and photosynthesis,affecting various aspects of plants’growth and metabolism.In response to this adversity,medicinal plants employ mechanisms such as morphological and structural adjustments,modulation of drought-resistant genes,and augmented synthesis of secondary metabolites and osmotic regulatory substances to alleviate the stress.Extreme water scarcity can lead to leaf wilting and may ultimately result in plant death.The cultivation and management of medicinal plants under stress conditions often differ from those of other crops.This is because the main goal with medicinal plants is not only to increase the yield of the above-ground parts but also to enhance the production of active ingredients such as essential oils.To elucidate these mechanisms of drought resistance in medicinal and aromatic plants,the current review provides a summary of recent literature encompassing studies on the morphology,physiology,and biochemistry of medicinal and aromatic plants under drought conditions.

早熟无限结荚习性大豆子粒生长特征(英文)

大豆产量潜力受到基因型和环境条件的制约。一种基因型的密度、植株分布决定其对太阳辐射、水分和养分的利用,进而高产的形成。当群体生长所需外界要素之一不能满足时,植株间形成竞争。产量的区域间及年际间差异与这种株间竞争关系密切,最终表现为单位面积内一个或多个产量构成因子的差异,如株荚数、荚粒数、或单粒重(籽粒大小)。本研究探讨籽粒大小在调节不同密度、行距条件下产量差异及年际间产量差异的作用。多点试验表明,籽粒大小在不同节位上及不同籽粒数的荚间差异不大。然而在2粒或3粒荚内,荚基部粒比中部及顶部粒小10%,而且子叶细胞体积差异不大。在改变源库、增强光照或遮阴条件下,籽粒大小发生变化。籽粒大小与子叶细胞数相关。籽粒大小是可塑的,但即使底部节位荚较顶部节位提前15～20d鼓粒,籽粒大小在所有节位间差异不大,所以籽粒大小与子叶细胞数的关系仍值得探讨。

Interactive effects of drought stress and chitosan application on physiological characteristics and essential oil yield of Thymus daenensis Celak

Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus.The interactive effects of foliar application of chitosan and drought stress on dry matter,essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400(iL L'1 chitosan applied to plants grown under field capacity, mild drought stress(50% field capacity), and severe drought stress(25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions,with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield(1.52 g plant-1) was obtained by application of 400 \iL L_1 chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.

Biofumigation: An alternative strategy for the control of plant parasitic nematodes

Plant-parasitic nematodes wreak havoc on the yield and quality of crops worldwide.Damage from these pests is estimated to exceed US$100 bllion annually but is likely higher due to misdiagnosis.Nematode damage may be catastrophic,but historically the solution has been damaging as well.Use of the synthetic nematicide methyl bromide(MBr)poses risks to the environment and to human health.Biofumigation,the use of plant material and naturally produced compounds to control pests,is an increasingly feasible method of pest management.The process acts through the growth or incorporation of plant material into the soil,that,over the course of its degradation,releases glucosinolates that break down into nematotoxic isothiocyanates.These secondary plant metabolites exist naturally in commonly grown plants,most of which belong to the Brassicaceae family.Research endeavors have increasingly explored the potential of biofumigation.The reaction of target pests,the selection of biofumigant,and ideal environments for efficacy continue to be evaluated.This review seeks to provide a cost and benefit assessment of the status of biofumigation for the control of plant-parasitic nematodes as an alternative to conventional methyl bromide usage.

Accumulation of L-DOPA in various organs of faba bean and influence of drought, nitrogen stress, and processing methods on L-DOPA yield

Faba bean(Vicia faba L.)has been identified as a rich source of L-DOPA,which is used in treating Parkinson's disease.Biosynthesis and accumulation of active substances such as L-DOPA in plant tissues may interact with growing conditions and processing methods.Accumulation trends of L-DOPA in various faba bean organs and the effect of drought stress and N fertilization on L-DOPA content were studied in a field and two greenhouse experiments.The influence of various processing methods on L-DOPA content of faba bean tissues was evaluated.The highest L-DOPA content was detected in fresh leaves(22.4 mg g^(-1))followed by flowers,young pods,mature seeds,and roots.Regardless of processing method,L-DOPA concentration in faba bean tissues was significantly reduced when tissues were boiled or dried.Among various methods of processing,freezing had the lowest detrimental effect,reducing L-DOPA concentrations by 24.1%and 21.1%in leaves and seeds,respectively.Drought stress elevated L-DOPA concentration,and maximum L-DOPA(23.3 mg g^(-1)of biomass)was extracted from plants grown under severe drought stress.However,L-DOPA yield(L-DOPA concentration×biomass)was compromised,owing to the adverse influence of drought stress on dry matter production.No significant difference in L-DOPA concentration was detected among various N application rates.

Agronomy, Nutritional Value, and Medicinal Application of Faba Bean(Vicia faba L.)

Faba bean(Vicia faba L.) is a cool season grain legume crop with the potential to be grown as multi-purpose crop in areas with short growing season. Faba bean is grown in many regions in the world due to its high nutritional value, medicinal effect, and effective biological nitrogen fixation. Diverse ecosystem benefits are expected from integrating faba bean in cropping systems. This paper specifically reviews the published work covering agronomic practices, nutritional values, medicinal benefits, and faba bean’s capacity for nitrogen fixation.