Reduced light and moderate water deficiency sustain nitrogen assimilation and sucrose degradation at low temperature in durum wheat

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• 作者：Imre Majlá ; th^a ; ^{majlath.imre@agrar.mta.hu" class="auth_mail" title="E-mail the corresponding author} ; Eva Darko^a ; Balá ; zs Palla^b ; Zoltá ; n Nagy^a ; Tibor Janda^a ; Gabriella Szalai^a
• 关键词：Abs ; absorptivity of incident light ; D ; mild water deficiency ; ETR ; apparent electron transport rate ; Fv/Fm ; maximal quantum efficiency of PSII ; gs ; stomatal conductance ; GS ; glutamine synthetase ; I ; normal irrigation ; LL ; low (reduced) light ; NIR ; near infrared light ; NL ; normal light ; NPQ ; nonphotochemical quenching parameter ; NR ; nitrate reductase ; PAR ; photosynthetically active radiation ; Pn ; net photosynthesis ; PPFD ; photosynthetic photon flux density ; PSII ; photosystem II ; R ; red light ; RO
• 刊名：Journal of Plant Physiology
• 出版年：2016
• 出版时间：1 February 2016
• 年：2016
• 卷：191
• 期：Complete
• 页码：149-158
• 全文大小：1057 K

文摘

The rate of carbon and nitrogen assimilation is highly sensitive to stress factors, such as low temperature and drought. Little is known about the role of light in the simultaneous effect of cold and drought. The present study thus focused on the combined effect of mild water deficiency and different light intensities during the early cold hardening in durum wheat (Triticum turgidum ssp. durum L.) cultivars with different levels of cold sensitivity.

The results showed that reduced illumination decreased the undesirable effects of photoinhibition in the case of net photosynthesis and nitrate reduction, which may help to sustain these processes at low temperature. Mild water deficiency also had a slight positive effect on the effective quantum efficiency of PSII and the nitrate reductase activity in the cold. Glutamine synthesis was affected by light rather than by water deprivation during cold stress. The invertase activity increased to a greater extent by water deprivation, but an increase in illumination also had a facilitating effect on this enzyme. This suggests that both moderate water deficiency and light have an influence on nitrogen metabolism and sucrose degradation during cold hardening. A possible rise in the soluble sugar content caused by the invertase may compensate for the decline in photosynthetic carbon assimilation indicated by the decrease in net photosynthesis. The changes in the osmotic potential can be also correlated to the enhanced level of invertase activity. Both of them were regulated by light at normal water supply, but not at water deprivation in the cold. However, changes in the metabolic enzyme activities and osmotic adjustment could not be directly contributed to the different levels of cold tolerance of the cultivars in the early acclimation period.