Salt-tolerance in Brassica juncea L. II. Salt-stress induced changes in polypeptide pattern of in vitro selected NaCl-tolerant plants

Summary The effect of salt-stress was studied on SDS-PAGE pattern of polypeptides in seedling, leaf and siliqua tissues of four genetically stable lines (SR2P1-2, SR3P2-1, SR3P6-1 and SR3P6-2) of in vitro selected NaCl-tolerant plants, a non-selected somaclone (CP5-2) and parent variety Prakash of Brassica juncea L. Seedlings were raised in 0, 50, 100 and 150 meq/l NaCl solutions and plants were irrigated with nutrient solution with 0, 30, 60 & 90 meq/l NaCl. Salinity induced distinct genotype specific changes in polypeptide pattern of leaf and siliqua tissues, while it had no effect on the polypeptide pattern of seedlings, radicle or hypocotyl tissues in any of the lines. In leaves, at vegetative stage, a high molecular weight protein of 53.2 kD while disappered at 60 mM and higher NaCl level in cv. Prakash and SR3P2-1, it appeared in SR2P1-2 and CP5-2 only at these higher salt levels and in SR3P6 lines it was present irrespective of stress conditions. Differences were also observed for a 93.8 kD protein which appeared anew under stress in cv. Prakash, CP5-2 and SR2P1-2, while it was absent in SR-3 lines. Intensity of the 57.3 kD protein decreased in cv. Prakash, increased in SR-2 and CP-5 lines whereas remained unchanged in SR-3 lines under salt-stress. In siliquae, salt stress induced the expression of four new polypeptides (56.1–70.8 kD) at 60 mM NaCl in cv. Prakash, and at 30 mM in SR2P1-2, SR3P2-1 and SR3P6-1 lines, while these were present in CP5-2 and SR3P6-2 even in the absence of NaCl stress.     

Genetic diversity in grasspea (Lathyrus sativus L.)

Genetic diversity was investigated in 348 accessions and subaccessions of grasspea (Lathyrus sativus L.) from 10 geographical regions. Polymorphism for 20 isozymes of 13 enzyme systems was studied to estimate the genetic diversity. The Near East and North Africa regions included the most variability for these isozyme systems, suggesting that the center of diversity (center of origin) for grasspea is in this general area. The lowest variability was found in accessions and subaccessions from South America, followed by those from Sudan–Ethiopia. Diversity was measured for individual loci over regions and EST-1 and SKDH had the highest genetic diversity. The closest genetic diversity was observed for LAP-2, followed by AAT-1 and PGM. The closest genetic distance existed between populations from the Near East and North Africa. Populations from South Asia and Sudan–Ethiopia, though geographically widely separated, exhibited a closer genetic distance from each other than from other regions.     

Anther culture of recalcitrant indica × Basmati rice hybrids

Fertile, green, di-haploid plants were obtained at high frequencies from several indica × Basmati rice F₁ hybrids and/or F₂ plant populations using an improved anther culture procedure. Anthers from cold-pretreated (10 ^°C for 10 d) panicles of six indica (HKR120, HKR86-3, HKR86-217, PR106, Gobind andCH2 double dwarf) and two Basmati rice (Basmati 370,Taraori Basmati) varieties and 14 heterotic indica ×Basmati F₁/F₂ hybrids were cultured in modified agarose-solidified N6M, Heh5M and RZM media. Best callus induction frequencies (2.6–78%) were obtained in RZM medium containing 4% (w/v) maltose,2,4-D, NAA and kinetin. F₂ plants compared to F₁ hybrids and parental rice varieties, were more responsive to anther culture. Androgenesis frequencies of 31–78% were obtained for indica × Basmati F₂ plants in RZM medium in just 30 d which are comparable to or higher than that reported for japonica rice varieties and hybrids involving japonica rice parent(s). Agarose (1.0% w/v)-solidified MS medium containing 3.0% maltose, kinetin, BAP, and NAA, induced green shoot regeneration in 0–51% of the anther-derived callide pending upon the genotype. High plant regeneration frequencies (67–337 green plants per 1000 anthers)were obtained from anther calli of several F₁hybrids (Gobind × Basmati 370 and HKR120 ×Taraori Basmati) and F₂ plants (Gobind × Basmati370, Gobind × Taraori Basmati, HKR86-3 × TaraoriBasmati). A sample of 498 plants obtained from the above hybrids, were transferred to pots with>90% survival; 8–78% of these plants had >5%spikelet fertility and were diploid. In addition,18% of the haploid plants could be diploidized by submerging in 0.1% colchicine solution for 16–18 h. The improved anther culture procedure reported here, resulted in several fold increase in the recovery of green plants from recalcitrant indica × Basmati rice hybrids compared to previous published procedures. The study may accelerate the introgression of desirable genes from indica into Basmati rice using anther culture as a breeding tool. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effects of a dietary protease‐complex on performance,digestive and immune enzyme activity,and disease resistance of Litopenaeus vannamei fed high plant protein diets

The effects of a dietary protease‐complex on growth performance, body composition, digestive and immune enzyme activity of Litopenaeus vannamei and its resistance to a pathogenic Vibrio parahaemolyticus were assessed in a 9‐week trial. A high fish meal diet (HF) containing 200 g kg^?1 fish meal and a low fish meal diet (LF) containing 100 g kg^?1 fish meal were designed as a positive and negative control respectively. Three other diets (LF+125P, LF+150P, and LF+175P) were manufactured by supplementing graded level of a protease‐complex (125, 150 and 175 mg kg^?1, respectively) to the LF diet. All diets were formulated to be iso‐proteic and iso‐energetic. Most performance indices of shrimp fed the LF+175P diets were similar to the HF diet. Among the digestive enzymes, trypsin, lipase and amylase activity in hepatopancreas of shrimp fed LF+175P diets (4576 U mg^?1 protein and 16, 32 U g^?1 protein, respectively) were higher than those fed the LF diets but lower than the HF diets (P < 0.05). Total superoxide dismutase and polyphenol oxidase contents in both serum and hepatopancreas were higher and serum malondialdehyde content and the cumulative mortality during disease challenge tests were lower for the diets containing the protease‐complex than those fed the LF diets (P < 0.05) with no difference with those fed the HF diets.     

Effect of combined shrimp and rice farming on water and soil quality in Bangladesh

This study analyzed water and soil quality and environmental impacts of shrimp farming in the southwestern coastal region of Bangladesh. Shrimp farming in the region is very traditional in nature where two culture systems viz. shrimp–rice and shrimp-only are being practiced, which are characterized by lower production, repeated stocking, irregular feeding, and fertilizing. Water quality in both farming systems was found suitable for optimum growth and survival of shrimp (Penaeus spp.). The level of 5-day biological oxygen demand (BOD₅) in both systems even in canal water was within the recommended level provided by the Government of Bangladesh which is less than 5 mg/l. Therefore, effluents of shrimp farms in the study area did not show any nutrient pollution on the surrounding environment. However, saltwater intrusion has caused many problems like loss of agricultural production, reduced availability of fodder for livestock, and fresh water for domestic uses in the coastal region. The findings of this study confirmed that shrimp farming using saline water have long-term effect of soil salinization. As a result, it poses a real threat toward sustainability of coastal shrimp farming as well as coastal development in Bangladesh.     

A global systematic literature review on sustainable soil management practices (1994–2022)

Sustainable Soil Management Practices (SSMP) offer potential benefits while conserving natural resources. However, the low adoption of SSMP limits the achievement of their full potential. To examine the current state of knowledge on SSMP adoption and identify research gaps, we systematically reviewed 269 peer-reviewed publications pooled from Scopus, Web of Science and ScienceDirect, covering the period from 1994 to 2022. We assessed the temporal and spatial transitions of SSMP adoption and identified a broad perspective of 14 themes on SSMP adoption and highlight the research trends and gaps. Prior to 2010, research on SSMP adoption was concentrated on a few themes and has become diversified in later years, covering emerging themes such as climate change and use Information and Communication Technology (ICT). Publications on SSMP adoption exhibited a global distribution, with particular emphasis on the African continent due to the flow of donors' funds driven by severe soil degradation and limited use of improved technologies in Africa. Studies on minimum soil disturbance were prevalent worldwide, with the highest number of publications. Our findings also indicate a strong research collaboration between developed and developing countries, showcasing donor-driven collaborative efforts and mutual benefits across different regions. This review however highlights the limited inclusion of local knowledge in SSMP promotion and recommends a bottom-up approach for future initiatives. In the discussion section, different critical factors of SSMP adoption covering farmers' perceptions, climate change, policy impact and the use of ICT are discussed. These findings and identified research gaps are useful for further research and the development of sustainable soil management policies, programmes and projects.