There should be some legal consequences for youths who share a joint with a minor once recreational marijuana is legalized in Canada, the Senate decided Tuesday.

Senators voted 42-31 to approve an amendment to Bill C-45 that would make it a summary or ticketing offence for a young adult to share five grams or less of cannabis with a minor who is no more than two years younger; it would be an indictable offence to share with younger minors or to share more than five grams.

They also voted 45-29 to require that any company licensed to grow marijuana must publicly disclose all its shareholders or executive members who are not based in Canada -- an amendment aimed at ensuring organized crime doesn't use offshore tax havens to wind up secretly controlling the recreational marijuana market.

And they approved, by a close vote of 39-36, another amendment that would specify that police who seize cannabis plants don't have to keep them alive.

That brings to 43 the number of amendments the Senate has so far approved to Bill C-45. And there are likely to be more before the bill is put to final vote in the upper house on Thursday.

The amendment approved Tuesday on social sharing among young people is actually less restrictive than the original draft of the bill, in which the government proposed to prohibit anyone 18 years of age or older from giving any amount of cannabis to a minor.

However, that was softened last week by the Senate's social affairs committee -- with the apparent blessing of the government -- in a bid to ensure that an 18 or 19-year-old who passes around a joint at a party with peers aged 16 or 17 doesn't wind up with a criminal record.

The committee approved an amendment that would have allowed a young adult to share an unlimited amount of cannabis in social settings with minors no more than two years younger. But that proved too lenient for senators Tuesday.

"Make no mistake, colleagues, it will be abused," Conservative Sen. Don Plett told the Senate as he moved to tighten the committee's amendment.

He argued that restricting social sharing to five grams of marijuana is reasonable, amounting to 10 joints. Giving any more than that to a 16-year-old "goes beyond social sharing and gets awfully close to trafficking," Plett contended.

He pointed out that it is illegal for an adult to provide alcohol to a minor and questioned why it should be any different for cannabis. But, in keeping with the government's stated goal of not criminalizing young people for cannabis use, he proposed making it a ticketing or summary offence to share small amounts of cannabis with a minor.

"There must be consequences," Plett said.

Liberal independent Sen. Art Eggleton, the chair of the social affairs committee, said he understands social sharing to mean kids passing around a joint at a party. But he acknowledged that the committee's amendment didn't define the concept -- a void that proved problematic for a number of senators Tuesday.

"To me, the simplest way of solving this is to actually have a definition of social sharing in the legislation," said independent Sen. Frances Lankin.

Tuesday's amendments are on top of the 40 amendments senators approved last week in accepting the report of the Senate's social affairs committee. The most significant of those would allow provincial and territorial governments to prohibit the home cultivation of marijuana plants, if they so choose, whereas the bill, as originally drafted, would allow up to four plants per dwelling.

In addition, senators last week approved another amendment that would tighten already stringent advertising restrictions on cannabis companies, preventing them from promoting their brands on so-called swag, such as T-shirts and ball caps.