Sharmila P, Kumari P Kusuma, Singh Kavita, Prasad N V S R K, Pardha-Saradhi P
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India.
Amity Institute of Biotechnology, Amity University, Noida, 201303, UP, India.
Protoplasma. 2017 Mar;254(2):763-770. doi: 10.1007/s00709-016-0988-5. Epub 2016 Jun 16.
Investigations were conducted to elucidate the key factor behind Cd-toxicity-induced proline accumulation in Indian mustard (Brassica juncea) by raising seedlings, independently in distilled water (DW) and mineral growth medium (MGM) in the presence of 0-500 μM CdCl. Invariably, Cd-induced toxicity, measured in terms of growth, was significantly more prominent in seedlings raised in DW than those raised in MGM. Cd brought about a significant reduction in growth and photosystem II activity with a concomitant increase in proline levels, in a concentration-dependent manner. Interestingly, the level of iron in shoots of seedlings decreased proportionately with increase in Cd toxicity. Cd-promoted proline accumulation was significantly higher in seedlings raised in DW than those raised in MGM. Depletion of essential cations (viz. Ca, Mg, K, and Fe) from MGM one at a time revealed that depletion of Fe leads to maximal proline accumulation under Cd toxicity. Interestingly, proline level in seedlings raised under Cd toxicity in DW supplemented with Fe was similar to that recorded in seedlings raised in MGM. Our results convincingly demonstrated that Cd-induced iron deficiency promotes proline accumulation.
通过在含有0 - 500 μM CdCl₂的蒸馏水（DW）和矿物质生长培养基（MGM）中分别培育幼苗，开展了相关研究以阐明印度芥菜（Brassica juncea）中镉毒性诱导脯氨酸积累背后的关键因素。始终如一地，以生长情况衡量，镉诱导的毒性在DW中培育的幼苗中比在MGM中培育的幼苗中显著更突出。镉导致生长和光系统II活性显著降低，同时脯氨酸水平以浓度依赖的方式增加。有趣的是，幼苗地上部分的铁含量随着镉毒性的增加而相应降低。镉促进的脯氨酸积累在DW中培育的幼苗中比在MGM中培育的幼苗中显著更高。一次从MGM中去除一种必需阳离子（即Ca、Mg、K和Fe）表明，去除Fe会导致在镉毒性下脯氨酸积累达到最大值。有趣的是，在添加了Fe的DW中镉毒性下培育的幼苗中的脯氨酸水平与在MGM中培育的幼苗中记录的水平相似。我们的结果令人信服地证明，镉诱导的缺铁促进了脯氨酸积累。
