The role of shoot-localized processes in the mechanism of Zn efficiency in common bean

Drought is a major constraint for common bean (Phaseolus vulgaris L.) production in México. Dehydrins are constitutive or stress-induced proteins related with a protective role of membranes and macromolecules against denaturation, thus preventing loss of their function. In this work, seed production and patterns of dehydrins accumulation in leaves and pods were evaluated in common bean cv. ‘Otomí’ subjected to drought, as compared with well-irrigated plants. Drought applied at pod formation and seed filling (SF) reduced yield up to 57 %. An antibody against a consensus sequence present in most dehydrins allowed for dehydrin identification. Two dehydrins of 82 and 73 kDA turned up both in leaves and pods throughout all the evaluated conditions. Presumably, both dehydrins are constitutive in the ‘Otomí’ cultivar. These dehydrins showed higher expression than controls in leaves after 6 d of drought at seedling and SF stages, and in pods 6 d after drought had started at SF. Increased expression might provide better protection during early stages of seedling and seed development. Increments on 63, 36 and 22 kDa dehydrin expression in pods at late SF might coincide with plant developmental programs, which prepare seed for desiccation. Dehydrins of 158, 54, 46, and 41 kDa were detected in pods 10 d after floral opening as a transient response to drought stress in SF. These results indicate dehydrins are relevant during plant development, as well as during drought stress.

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Influence of Tytanit® and EM on biochemical, physiological, and qualitative parameters of common bean

Horticultural Science ◽

10.17221/72/2020-hortsci ◽

2021 ◽

Author(s):

Alicja Auriga ◽

Jacek Wróbel

Keyword(s):

Common Bean ◽

Absorption Spectrometry ◽

Nutrient Content ◽

Dry Mass ◽

Stress Factors ◽

Effective Microorganisms ◽

Substantial Impact ◽

High Yields ◽

Positive Effect

The role of preparations supporting plant growth is mainly to reduce the harmful effects of various stress factors on plants and to ensure high yields of good quality. This experiment compared the effect of the mineral stimulator Tytanit® and the biological preparation Effective Microorganisms (EM) on the physiological and biochemical activity, as well as the yield of the common bean (Phaseolus vulgaris L.). The photosynthetic pigments, free proline and malondialdehyde were assayed and compared at three phenological phases of the bean: 15 BBCH, 24 BBCH, 65 BBCH. The yield parameters included the average number of pods per plant, as well as their fresh and dry mass. Additionally, the nutrient content in the pods was determined according to the atomic absorption spectrometry method. The study revealed a positive effect of both preparations on increasing the content of chlorophyll a, b, and the carotenoids in the bean leaves. Plants treated with Tytanit® were characterised by the highest content of malondialdehyde and proline, while EM maintained the aldehyde content on a similar level compared to the untreated plants and significantly reduced the proline content. Both preparations significantly decreased the Mn, Mg, P, and Ca content in the pods and did not have a substantial impact on the yield.

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The importance of the traditional milpa in food security and nutritional self-sufficiency in the highlands of Oaxaca, Mexico

PLoS ONE ◽

10.1371/journal.pone.0246281 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246281

Author(s):

Ivan P. Novotny ◽

Pablo Tittonell ◽

Mariela H. Fuentes-Ponce ◽

Santiago López-Ridaura ◽

Walter A. H. Rossing

Keyword(s):

Food Security ◽

Common Bean ◽

Smallholder Farmers ◽

Cropping Systems ◽

Negative Consequences ◽

Subsistence Farmers ◽

Self Sufficiency ◽

The Common ◽

Global Food

Around 30% of global food is produced by smallholder farmers, yet they constitute the most food-insecure group. In Mexico, food self-sufficiency is declining. Rural policies in the country have stimulated the production of cash crops to the detriment of the traditional intercropping system, the milpa. Such a decline may have negative consequences for the food security of subsistence farmers. This study aimed to assess changes in nutritional self-sufficiency over the last 30 years and the role of milpa systems in food security for two communities in the highlands of Oaxaca, Mexico. The study used satellite images, censuses, and field data to estimate food production. Three cropping systems, monoculture of maize, monoculture of common bean, and the milpa were compared in terms of nutrients and vitamins produced. Furthermore, a household typology was developed for each community to contrast nutritional self-sufficiency levels between the different household types. Results showed that the milpa produced more volume of food per area compared to the other systems. The milpa also produced all the nutrients and vitamins (except for B12) required to feed at least 2 persons ha-1. Monocultures of maize lacked vitamins A, B9, B12, and C, and the common bean lacked vitamins A, B12, and C. While farmers recognized the importance of the milpa, they preferred monocultures due to the reduced labor demands of this system. Households that obtained most of their income from off-farm activities had the lowest nutritional self-sufficiency. Enhancing nutritional self-sufficiency through crop diversification has the potential to not only improve the nutrition of subsistence farmers, but also to enhance ecosystem service provision, promote biodiversity conservation and restoration, and improve resilience to climate change.

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